Page 1

■ Ride Height Sensor Types

■ On-The-Car Brake Lathe Myths

■ Nissan Brake Tips



MAGAZINE April 2013

Reader Service: Go to

Reader Service: Go to

TECH FEATURE: ABS Solenoid Diagnostics






Nissan Brake Job

ABS Solenoid Diagnostics

Fighting noise-related complaints. Nissan makes use of the simple and effective tab-type sensor that will contact the rotor when the pads need to be replaced.

A look inside the HCU. The ABS computer or HCU is a node on a high-speed vehicle bus. This means that the information can be typically accessed through the OBDII DLC.


Changing Your Mind, Not Rotors How do you handle pulsation or a comeback?

You may think that installing new rotors eliminates the possibility of a comeback. However, this myth creates more comebacks that it solves. Publisher Jim Merle, ext. 280 email:

Managing Editor Tim Fritz, ext. 218 email:

Ad Services Director Cindy Ott, ext. 209 email:

Editor Andrew Markel, ext. 296 email:

Technical Editor Larry Carley

Circulation Manager Pat Robinson, ext. 276 email:

Graphic Designer Dan Brennan, ext. 283 email:

Reader Service: Go to




6 Publisher’s Perspective 8 Viewpoint 12 Industry Review 14 Gonzo’s Toolbox 20 Diagnosing Accelerometers 22 Alignment Specs: Jeep 42 Ride Height Sensors 46 Tech Tips 48 Product Showcase 51 RAPID RESPONSE 52 Classifieds 56 Brake Lights

HOME OFFICE 3550 Embassy Parkway Akron, Ohio 44333-8318 330-670-1234 FAX 330-670-0874


PRESIDENT Bill Babcox 330-670-1234, ext. 217 VICE PRESIDENT Jeff Stankard 330-670-1234, ext. 282


Sales Representatives: Bobbie Adams 330-670-1234, ext. 238 Doug Basford 330-670-1234, ext. 255 Sean Donohue 330-670-1234, ext. 206



IN THIS ISSUE: Publisher’s Perspective Auto-Video Inc. ABS Solenoid Diagnostics Brake Lathe


6 27, 39 30 36

Brake and Front End is a member of and supports the following organizations:

Dean Martin 330-670-1234, ext. 225 Glenn Warner 330-670-1234, ext. 212 John Zick 949-756-8835 List Sales Manager Don Hemming 330-670-1234, ext. 286 Classified Sales Tom Staab 330-670-1234, ext. 224

BRAKE & FRONT END (ISSN 0193-726X) (April 2013, Volume 85, Number 4): Published monthly by Babcox Media, 3550 Embassy Parkway, Akron, OH 44333 U.S.A. Phone (330) 670-1234, FAX (330) 670-0874. Periodical postage paid at Akron, OH 44333 and additional mailing offices. POSTMASTER: Send address changes to BRAKE & FRONT END, P.O. Box 13260, Akron, OH 44334-3913. BRAKE & FRONT END is a trademark of Babcox Publications, Inc. registered with the U.S. Patent and Trademark office. All rights reserved. A limited number of complimentary subscriptions are available to individuals who meet the qualification requirements. Call (330) 670-1234, Ext. 260, to speak to a subscription services representative or FAX us at (330) 670-5335. Paid Subscriptions are available for non-qualified subscribers at the following rates: U.S.: $69 for one year. Canada: $89 for one year. Canadian rates include GST. Ohio residents add current county sales tax. Other foreign rates/via air mail: $129 for one year. Payable in advance in U.S. funds. Mail payment to BRAKE & FRONT END, P.O. Box 75692, Cleveland, OH 44101-4755. VISA, MasterCard or American Express accepted.

4 April 2013 |

Reader Service: Go to

» Publisher’s


By Jim Merle | PUBLISHER



f not, don’t miss the excitement provided by Augmented Reality (AR) technology powered by AVI PLAY within the pages of Brake and Front End. Once you’ve downloaded AVI PLAY, open the App and hold your smart device over this page to unlock a special message from me. We launched our AVI PLAY App last month, providing a seamless transition from the pages of Brake and Front End to digital information on your mobile device in the form of video, 3-D imaging and other exciting types of content supported by AR. Are we heading down the right path? I believe we are, and so does Apple. Apple is quickly moving into Augmented Reality in an attempt to stay ahead of its customers’ expectations. They have identified Augmented Reality as a new content channel with a plethora of applications that includes education; we have a similar strategy in place. Each issue of Brake and Front End will continue to include insightful technical features in print, supplemented by relevant video content powered by AVI PLAY. And there’s more. Watch for our advertisers taking advantage of this technology by bringing an additional dimension to their advertising and promotional messaging.

Start now by downloading AVI PLAY by following these two easy steps: Step 1: From your Apple or Android

Step 2: Open the AVI PLAY App. Once

smart phone or tablet, visit to download AVI PLAY.

it’s downloaded, hold your device over this page to unlock a special request from me.

Share your thoughts by contacting me at 330-670-1234 ext. 280, or by e-mail at


April 2013 |

Reader Service: Go to

Viewpoint By Andrew Markel | EDITOR


Buy local online ads cheap


his past month, I started purchasing Google AdWords to promote a website on brake safety. It gave me a whole new perspective on what is happening to online and mobile advertising. Google AdWords allows you to bid on and purchase textbased ads that appear on the top, bottom and sides of a search page results for specific search term when inputted by a “Googler” (AKA: potential customer). A company only pays if a person clicks on an ad. Prices and keywords are set by the buyers in a live auction and are driven by search traffic and clicks. Where it gets interesting is when an ad is “enhanced” to target people in a business’s vicinity by using an computer’s address or the GPS signal of a smartphone. Terms like “brake job,” “warper rotor” or “tune up” can be very expensive because of the close association with a poten-


April 2013 |

tial repair or parts purchase. These consumer searches terms can cost more than $3 a click without enhancements. If the advertiser targets a particular location or demographic, the click can sometimes cost an advertiser an extra $2. Who would pay $3-$6 if someone clicks on a link to their website? The answer is surprising; 1.2 million businesses use these ads and Google claims that every dollar spent in their network results in $2 of revenue. They must be doing something right. If you want to get a little taste of this type of advertising, go to and search the


phase “brake job” and see what comes up. If you are on your desktop computer, at the top of the search results are probably ads for major chains, dealers or parts stores. The ads may include the address of the closest location. If you were to view it on a smart phone or tablet, the links to location could open up a GPS navigation app or the shops phone number could be dialed with just one click. The order of the ads depends on who paid the most for the search term in a given area. It is not based on who has the best website or best brake jobs. The ad at the top of the page may cost $3.00 while the ad at the bottom or in the right hand column may cost as little as .50¢. Should your shop purchase Google AdWords? Yes, and no. If you are looking to expand your customer base, AdWords can be cost effective way to target new customers in your area. But, it can be labor-intensive and somewhat addictive. You might find yourself constantly checking to make sure a competitor has not out bid you for a keyword. Or, you can try to find less expensive yet just as effective search keywords. In terms of cost, you set how much you want to spend per day, you are not locked into a contract. If it is slow and you need to fill the bays you can specify $50 a day. If business is going well and you are booked for the week, you can cut back to $10 a day, or even Go to

deactivate the ad until you need customers. Is it easy to set up? Yes, go to to set up an account. Google has done a great job creating video tutorials and they have call centers with intelligent representatives that can help you manage your account. There is a statistic often quoted by internet “gurus” and journalist that goes “9 out of every 10 mobile phone Internet searches results in some type of action, such as a website visit or phone call.” It is a power statistic if it is true. For the independent shop with one or two shops, AdWords can allow you to compete with new car dealers and chains in the mobile and location base advertising arena, if you are willing to pay for the clicks. ■ How did the AVI Play Augmented Reality App work in the Brake & Front End March Issue? How is it working in this issue? Looking at the number of downloads from the Apple Store and Android Marketplace, the app has been a success! But, I want to hear from you the reader to see if there is any way we could improve the experience or if you think there are some topics, like ABS repairs, that should be Augmented. Send me an email at Thank You!

Industry Review


Successful 2013 APA Conference Delivers Networking Opportunities and Business-Building Tools, Awards Vendors Automotive Parts Associates’ (APA) 32nd annual Shareholders’ & Manufacturers’ Conference, held March 14-16 in St. Augustine, FL, boasted 310 people in atten-


dance, building on the momentum of last year’s successful event. It took place at the Renaissance World Golf Village Resort. Serious about fueling their business suc-

Reader Service: Go to April 2013 |

cess, the 66 members and 74 vendors in attendance engaged in several networking opportunities and participated in unique Oneon-One meetings. The Manufacturer One-on-Ones gave APA shareholder members the opportunity to discuss business-related issues, learn about new products and programs, and take advantage of great show specials being offered by the APA vendors. Thousands of dollars and gift items were given as door prizes throughout the day. The general session kicked off with opening comments by Dan Freeman, APA president and CEO. Then, keynote speaker Tim Knox, shared common sense business advice in the areas of customer service and leadership. Knox advised that good leaders lead by their actions andtheir words, shared knowledge enhances the team spirit within your company, and great customer service hinges on your employees’ attitude, experience and training. Knox also provided these “words of wisdom” to ensure business success: Expect the unexpected; ensure open communication among your employees; be flexible and willing to ask for help; always be positive (negativity kills productivity); build relationships; fun engages your employees and drives dedication; first impressions really do count; job descriptions can be limiting and squelch creativity; and seek out and hire “intra-preneurs” — those who think they are one of the business owners and, therefore, are driven by job satisfaction and a growth plan.

Industry Review Advance Auto Parts Professional Rolls Out Coverage Increases For MotoLogic Repair And Diagnostics Advance Auto Parts has announced the addition of OE repair and diagnostic information for manufacturers Audi, Mazda, Mercedes and Volkswagen to MotoLogic, the company's repair and diagnostic software tool. Fast navigation; accurately rendered, original OE content; and extraordinary ease of use have made MotoLogic a best-in-class repair and diagnostic service, according to Advance. The company says the depth of information and ease of access available within MotoLogic is unrivaled in the industry, and included in the rollout of additional manufacturer coverage is the addition of service information for older-model vehicles dating from the early 1990s to the 1950s. “The demand we’ve seen for high-quality and accurate auto repair information has driven MotoLogic’s immediate success among our commercial customers,” said Walter Scott, vice president of eCommerce and eServices for Advance Auto Parts. “We’re offering shops

an easy, accessible solution for their repair and diagnostic needs. The continued expansion of our manufacturer coverage and support team dedicated to MotoLogic ensures that we’re delivering the information that garages need to fix vehicles fast, all with just a few clicks of the mouse.” The fully searchable, OE diagnostic and repair resource for the automotive service and repair sector features a state-of-the-art search engine that ensures faster results. In addition to speed, MotoLogic’s detailed search engine lets technicians access OEM service information, clickable and color-coded OEM wiring diagrams, service bulletins, diagnostic flowcharts with sophisticated hyperlinks, component locators, labor times, owner’s manuals and more — all in the time it takes to click “Search.” For further information, visit or call 855-222-1632 for direct assistance. ■

Reader Service: Go to 13

Gonzo’s Tool Box By Scot t “ Gonzo” Weaver

Understanding Electrical Circuits Will Expedite Diagnostic Repairs


work order comes to you with this complaint: “My turn signal indicators light up when I step on the brake pedal or when I’m driving at night.” Do you have a good idea what the problem is? Or, are you completely lost and debating sending this job to another shop because it’s not something you think you can handle? Let’s see if I can simplify the problem for you and retain this customer for your shop. Before making the repairs, it’s important to first understand how things are supposed to work. So, what are you looking at? Essentially, you’re witnessing an electrical current trying to finish its journey from positive to negative. This can only happen if the vehicle is equipped with a dual-filament bulb in the rear of the car, where the turn signal and brake are combined into one bulb filament. In order for this to happen, there has to be a good bulb in the circuit. (If there is a broken filament in the bulb, you won’t see this phenomenon.) In regard to the original complaint, this cannot happen any other way than what was described in the work order. There is a similar occurrence with the front bulbs, but, in that case, only the indicator is on and the brakes do not affect it. Very simply put, it’s a bad ground signal at or near the bulb or bulb housing. A lot of manufacturers have gone to these one-piece bulb housings in the rear sections and they can be very problematic and lead to many false diagnoses if they are not properly checked. The housings can melt the connection from the bulb to the socket or, in many cases, melt the connection between the harness and the housing. Always disconnect the housing from the harness and examine both


April 2013 |

the connector and the housing for deformation, melted leads or discoloration.

HOW TO SPOT THE PROBLEM The first thing to do in any diagnostic procedure is to duplicate the problem. Since this can only happen with a dual-filament bulb where the brake/turn lights are combined, you can safely assume that the problem is coming from the rear of the vehicle. As you turn on the signal, observe the condition on the cluster as you apply the brakes. Unless both rear bulbs have lost their ground signal simultaneously, you should easily spot which side is the problem area. Keep in mind that as you flip on the turn signal (with combined turn/brake light systems), you are essentially turning “off” one of the brake lights, thus blocking the electrical signal to that individual bulb filament. One side will work correctly while holding the brake on, and when flipping the turn signal in the opposite direction, the feedback will show up on the dash with one turn signal indicator lighting up at the same time that the other one is flashing.

CONFIRM THE DIAGNOSIS The only tool I use for this procedure is a good old-fashioned test light. Before getting out of the car, turn on the hazards and the parking lights. (This is another good pre-test.) Now, go to the rear of the vehicle and you’ll notice one side of the car is not illuminated. This should coincide with your early test results. Next, remove the housing and find a good ground for your test light. Then, test the three leads to the bulb. With the hazards and the parking lights on, two of them should be work-

Reader Service: Go to

Reader Service: Go to

Reader Service: Go to

Gonzo’s Tool Box

ing — one will be flashing and one will be on solid. If you’re in the right area, you’ll find out there’s going to be another lead showing positive current. Since your test light is grounded, you’re actually seeing a completed circuit when you touch the test light to the (bad) ground lead. This all starts from the true positive lead, then through the bulb filament, then through the ground lead and, finally, through your test light. (A good ground would not light up the test light.) In a lot of cases, the bulb filaments might even start to show signs of a dim output, because you have provided a small trace of a negative feed into the circuit by way of your test light. At this point, I’ll use a jumper wire attached to a good ground and touch it to the “real” ground wire for the circuit. If there are no other breaks in the connections through the housing or the wiring, the bulb should start working normally.

SPECIAL NOTES Keep your test light probe lead as sharp as possible. Also, when probing a lead, do not

use the probe in the actual socket; instead go from the backside of the connector. This way, you avoid spreading the connector open and creating a new problem. When I’m in an area where I can’t get to the rear of the connector, or it’s sealed, I use a sewing needle-size safety pin or a quilter’s pin (it has a “T” handle top that’s easy to hold on to) to stab the wire. It leaves a very small mark that almost completely disappears when removed. I also make up my own jumper wires from a roll of flex wire (not standard wire); I try to make them all about 2½ feet in length. This seems to be the best length for maneuvering around and from sideto-side in a car. It’s an easy repair and an even easier diagnosis once you understand the fundamentals of how these electrical circuits operate. With a bit of practice, you’ll find electrical repair is easier than you thought and you’ll be able to retain a lot more work in your shop, as well as keep more customers coming to your door. ■ 19


Diagnosis of Accelerometers


ccelerometers measure gravitational pull in gravitational force or G-force. Some cars will have one or two sensors depending on sophistication of the system. Some systems group the accelerometers in a sensor cluster. The typical sensor may cost $400 to $800.

LATERAL/TRANSVERSE These sensors are typically found under the center console near the vehicle’s center of gravity. Your scan tool will read the sensor output in G-force or G. A typical road vehicle will be able to corner around one G. Single-seat race cars can corner at 4- to 5-Gs. Most production car accelerometers have a limit of 4-Gs.

with three wires. These include a 5-volt power, ground and signal wires. The signal wire will vary the voltage from 0-5-volts depending on G-force.

SENSOR REPLACEMENT Whenever an accelerometer is replaced, it must be recalibrated. Also, some sensors must be tightened in a specific procedure. A loose accelerometer can generate codes because it will be measuring vibration and not G-force.

LONGITUDINAL These sensors measure braking and acceleration. This can be used to determine how hard the driver is accelerating or braking. Longitudinal sensors can also be used to calculate the angle of the vehicle for hill holding. It is very difficult and even dangerous to drive the vehicle and look at the readings from an accelerometer. You will see only minor movement in the sensor. The best way to measure the performance of an accelerometer is to rotate it 90 degrees. When a lateral accelerometer is rotated 90º, it should read 1-G. When a longitudinal sensor is rotated on its end, it will read 1-G. This is because gravity is equal to 1-G. Most accelerometers are wired Go to

YAW SENSORS A yaw sensor measures the vehicle’s rotation around its vertical axis, while at the same time measuring the acceleration at right angles to the driving direction. By electronically evaluating the measured values, the sensor is able to differentiate between normal cornering and vehicle skidding movements. Yaw rate is measured in degrees per second. If you have a vehicles making a 90º turn in two seconds, it would have a yaw rate of 45º. The Yaw rate sensor and accelerometers will often be mounted in a sensor cluster. To test a yaw rate sensor, rotate the unit so it is on a corner. The yaw sensor should react. ■

Reader Service: Go to

Alignment Spec Sponsored by:

2002-2010 Jeep Liberty


Go to


April 2013 |

he Jeep Liberty (2002-2007 KJ+2008-2010 KK) was the replacement for the Cherokee (XJ). The major changes from the Cherokee to the Liberty were an independent front suspension and trailing arm rear suspension. Compared to the Cherokee, the Liberty is actually easier to align. WARNING: On 2008-2010 KK models, the front knuckles are aluminum and the ball joints and tie-rod ends need to be torqued and turned an additional 90 degrees. The upper ball joint and tie-rod have a torque spec of 30 ft/lbs. Lower ball joints have a torque spec of 40 ft/lbs. Failure to follow the proper torque procedure will result in damage to the knuckle. Instead of having to install off-

set ball joints and shims to adjust camber and caster, the adjustments are performed with the cam bolts in the lower control arms. The rear is not adjustable. Overall, the Liberty is an easy vehicle to align. But, pay attention during the initial inspection.

FRONT SUSPENSION The Liberty’s front suspension uses upper and lower control arms. The replacement of the upper control arms can be tedious and require the removal of battery tray, power distribution center and other components to get at the passenger side upper control arm. If serviced, the control arms

Alignment Spec should be tightened with the vehicle at normal ride height due to the bushings. It is important to have the springs supporting the weight of the vehicle when the fasteners are torqued. If springs are not at their normal ride position, premature bushing wear may occur. The control arms are robust, but the stock ball joints proved to be the weak link. Jeep issued five recalls concerning ball joint failure for various 2002-2006 models. Most of the recall documents site corrosion of the joint as the cause of the failure. The culprit was water intrusion which was often blamed on poor sealing of the boot and/or missing heat shield on early models that allowed the boot to be degraded. The upper joints should have zero play. The lower joints should have no more than 1.5mm of end play. To measure the lower ball joint, the suspension needs to be loaded. Attach a dial indicator to the base of the lower control arm and align the dial indicator’s contact point with the direction of the stud axis, touch the machined flat surface on the knuckle and zero the dial indicator.

There should be no play in this joint. If it is worn, it may not change the thrust angle, but it will make noise. On 2008 and up KK models, Jeep changed the rear suspension and ditched the single upper control arm for a four-link setup with a lateral link. â–

REAR SUSPENSION The rear suspension on the Liberty is non-adjustable and the only specification is for the thrust angle. When taking the initial readings, pay attention to the thrust angle and suspension setback. If the thrust angle is greater than specifications, inspect the rear suspension for damage or worn bushings. On 2002-2007 models, the single upper control link looks like a boomerang and utilizes a single ball joint mounted to the axle. Reader Service: Go to

Brake Job

Nissan Cars By Bob Dowie


he most common complaints are noise-related. Nissan, like many other manufacturers, makes use of the simple and effective tab-type sensor that will contact the rotor when the pads need to be replaced. The resulting, high-pitched squeaking noise has proven to be very effective in getting the driver’s attention. That’s not to say that people won’t ignore it; rather they drive until the brakes are making that distinctive grinding noise that indicates the friction material is gone and metal-to-metal contact is taking place. Of course, in that case, the car should be parked until repairs are made. Any noise that is more than occasional should be investigated. Some noise will be the result of rust on the rotors, calipers, hardware or even the brake pads themselves. Use only the best parts, replace questionable units and make sure that the brake hardware is in good condition or new. Also make sure that all the metal-tometal contact areas are being lubed with the proper grease that’s designed to do this tough job in a harsh environment. The rotors come into play again if you’re faced with a brake-related vibration. The most common is a vibration while braking that’s caused by uneven rotors with excessive thickness variation or runout.

With high-mileage vehicles, you could be faced with a “brake pedal sometimes fades to the floor” complaint. Although it’s not a common complaint on Nissans, a little detective work is required in such cases. If the pedal fades as the vehicle comes to a stop, often in a situation where the pedal is being partially applied in anticipation of coming to a full stop, it’s a safe bet the master cylinder is the culprit. If, on the other hand, the condition results from a long ride at highGo to

Reader Service: Go to

Brake Job way speeds, it’s likely that excessive drag is causing the fluid in the calipers to overheat, resulting in brake fade. When the brakes cool, the pedal often will return to what feels like “normal” to the customer. Many times, the customer will report a burning smell and the worse cases will cause a severe vibration. It takes a stuck caliper to generate the degree of heat needed to cause these problems, and they certainly should be checked closely. Nissan uses a hand-brake that is incorporated into the rear caliper. We know everyone doesn’t use his or her hand-brake on a regular basis, and we also know that a mechanical device doesn’t like to sit around not being used only to suddenly be forced into service. The same thing can be said for the cables. If the hand-brake levers aren’t returning on the caliper, be sure that the cables aren’t binding. The complexity of the hand-brake does make the rear calipers a little pricier, but I still like to replace them in pairs to maintain the balance of the brake system.

Reader Service: Go to

26 April 2013 |

ABS AND VSC SYSTEMS While the ABS system on the Nissans has proven to be quite reliable, there have been reports of some problems but, more importantly, it has changed the way we perform brake service. While it has always been important to practice good work habits, with the brake system now being integrated into both the anti-lock brake system and the vehicle stability control system, it’s more important than ever that the mechanical application and release takes place as expected. Equally important is the quality of the fluid and our responsibility to maintain it. The first step is to never push the dirty fluid backward through the system taking the risk that you’ll plug up a port in the ABS controller that will lead to replacement of this expensive unit. Always open the bleeder at the caliper before pushing the piston back, attach your bleed line catching the dirty fluid and never miss an opportunity to flush the brake system. And, at the very least, a thorough flush and bleed should be performed whenever the pads are replaced. When it comes to problems you may see with the ABS system, most will be related to wheel speed sensors not reporting the wheel speeds correctly. The challenge is finding out why the signal is wrong. The first step is to pull the

Brake Job codes, the second step will have you checking the service information and forums for TSBs and other information that will help in the diagnostic process. As an example, there is a TSB for the 2005 Maxima related to the rear speed sensors and hub and assembly mounting surface. Also keep in mind that like engine codes, brake and ABS codes are circuit-specific and not sensor-specific. Always confirm the code by checking the signal at the sensor. If you’re getting the expected signal at the sensor and the code persists, confirm the signal at the control unit as there have been some reports of harness problems. Other than the ABS or traction control warning lamp being lit, the most common problem you’ll see will be unwarranted ABS engagement. This will often be the result of a wheel speed signal dropping out at low speeds. When diagnosing this problem, the first step is to identify the wheel that’s dropping out, then determine why; in this case, it may be the sensor, but it could just as easily be a cracked tone ring, or corroded connections in the harness. It doesn’t take long to check for either and, as always, a solid diagnosis will lead to a solid and profitable repair. To turn these kinds of jobs into profit-makers, get in the habit of checking your service information. Check for TSBs, or even more valuable websites such as ■



Go to

ike the Prius and other high-voltage hybrid vehicles, the high-voltage battery packs enough energy to cause a potentially lethal shock should you accidentally come into direct contact with any of the orange-color coded high-voltage wiring or hybrid components. Note: For this reason, the high-voltage battery should always be isolated before doing any electrical repairs or other work that might bring you into contact with any of the hybrid components. Removing the smart key from the vehicle won’t protect you. The high-voltage battery must be isolated by flipping the power disconnect switch located inside the trunk. Make sure the READY light is out before you do this, otherwise it could cause a “malfunction,” according to Nissan. Wear heavy, rubber-insulated gloves that are rated to withstand up to 1,000 volts to pull the disconnect switch. Also, do not press the start/stop button when the high-voltage battery has been isolated from the system. This can also cause problems with the electronics and set false codes because the system can’t connect to the high-voltage battery. Ordinary maintenance such as changing the oil, filters, coolant, etc., or working on the brakes, does not require isolating the high-voltage battery. But any work on the powertrain or hybrid components does require isolating the 244.8-volt battery, and waiting at least 10 minutes before starting any work so the capacitors inside the inverter can discharge (they also store enough energy that could give you a bad shock). ■

Reader Service: Go to



he ABS computer or HCU is a node on a high-speed vehicle bus. This means that the information can be typically accessed through the OBDII DLC. The ABS controller/modulator is the heart of any ABS or ESC system. The modulator gets the brake pressure from the master cylinder. Inside are the valves and solenoids that control the pressures to the wheel. During normal operation, the pressure from the master cylinder goes through the HCU unaltered. ABS is the foundation of the ESC system. ESC systems add software and sensors like Yaw,

steering angle and even control of the throttle to keep the vehicle under control. A basic ABS four-channel system will have eight solenoids (4 isolation/4 dump) or two for each wheel. Some systems will have more solenoids or valves to isolate the master cylinder from the HCU. ESC systems will typically have 12 or more.

APPLY When the master cylinder applies pressure it goes directly to the wheel because the outlet/dump solenoid is closed. This is a normal braking event. The unit is in a “passive” state.

HOLD If the system senses a wheel is locked, the inlet/isolation solenoid is closed to prevent any more pressure from the master from reaching the wheel. The wheel might start to turn.

RELEASE If the wheel does not start to turn, the outlet/dump valve will open. This will release or bleed off the hydraulic pressure that is holding the wheel. The wheel will now rotate.

REAPPLY Since pressure from the master cylinder has been bleed off, the pump in the HCU will spool up and apply pressure. The outlet valve is closed and the inlet valve is opened. The pump applies pressure to the wheel. If the wheel is still outside the wheel slip parameters, the cycle will start over. This happens very quickly. The operation of the solenoids and pump will cause a “kick back” or pulsation in the pedal.


April 2013 |

Reader Service: Go to


HCU MECHANICAL PROBLEMS Mechanical issues with the HCU are rare, but they can happen. Valve seats and pintles can become stuck or not seat properly due to debris, corrosion or contaminated brake fluid. If the inlet/isolation valve is stuck open, it will not affect normal braking in any way. It will only hurt the ABS system. This could lead to a pulling condition during ABS activation. If an outlet/dump valve is stuck open in one circuit, this could cause a pull condition during normal braking. This is due to the loss of brake pressure at a wheel. Typically, this is not discovered until brake hoses, calipers and other parts have been replaced.

TESTING SOLENOIDS ELECTRICALLY Sometimes a stuck or defective solenoid or pump will set a code. A solenoid has a resistance between 2 and 8 ohms. On some units, it is impossible to access the individual solenoids. Testing of the unit with a scan tool with bi-directional control might be the best way to confirm the condition of the HCU. Most vehicles equipped with ESC will have 12 valves or solenoids in the HCU. Eight solenoid control the wheels. Four additional solenoids can block off the master cylinder and allow the pump to send pressure to a specific wheel. Understeer is a condition where the wheels are turned, but the vehicle continues to travel in a straight line. This is sometimes described as a push. The ESC computer would see this event through the sensors. The wheel speed sensors in the front 32 April 2013 |

typically read slower than the rears. The computer would also see that the steering angle is greater than the intended path. The ESC system needs to intervene before the event occurs. It needs to anticipate the problem and correct as the vehicle travels. This is what the ESC sees during an understeer event. The SAS angle is at +52Âş, this means that the customer has the wheel turned to the right at a significant angle. Even with the steering wheel turned, the yaw and accelerometer read like the vehicle is going straight. The APPS or throttle pedal position sensor shows the driver is off the gas and the brake pedal is not pressed. The deciding information for the system is in the wheel speed sensor inputs. Between the front and rear there is a 6 to 9 mph difference between the front and rear speeds. The front wheels are traveling slower than the rears. â–

Reader Service: Go to


QUALITY YOU YOU CAN CAN TRUST TRUST Restore “like “lik likke new” new performance with Duralast Duuralast brake parts. parts They’re They re designed for performance performa and quality that match that of original equipment. Ask your Commercial rcial Sales Manager about a today.. Duralast brakes today

Get Proven Tough Duralast brakes – the Official Brakes of NASCAR.

Reader Service: Go to


NASCAR is a registered trademark of National Association for Stock Car Auto Racing, Inc. Š 2013 AutoZone, Inc. All Rights Reserved. AutoZone, AutoZone & Design, Duralast and Duralast Gold are registered marks and Duralast Gold Cmax and Duralast Gold SD are marks of AutoZone Parts, Inc. All other marks are the property of their respective owners.

Brake Lathe

Changing Your Mind, Not Rotors


ow do you handle a pulsation or comeback? Blame the pads? The driver? Defective rotor? When you point your finger at these items, there are three fingers pointing back at YOU.

MYTH 1: Machining rotors is unprofitable Labor in a shop does not take up inventory and does not have to be delivered by a parts store. You just have to make it a line item on the repair order instead of giving it away with every brake job. You may think that installing new rotors eliminates the possibility of a comeback. However, this myth creates more comebacks that it solves. These comebacks often start with blaming the new pads, and ends with the customer having to return a second or third time until someone pulls out a dial indicator and micrometer. Installing new rotors is not a way to avoid hav-

ing to use a micrometer or dial indicator. For every brake job, you should always measure for runout (rotor and flange) and the dimensions of the rotor before brake service is performed. After the rotor is resurfaced or a new rotor is installed, the rotor should be measured for runout when it is installed on the vehicle as a quality control method. A new rotor could have excessive runout when it is installed on the vehicle due to a stacking of tolerances.

MYTH 2: New rotors prevent comebacks and are cheaper and more profitable than an on-the-car lathe In some cases with excessive runout, a new rotor should be machined to match the vehicle. It has often been said that you should never machine new rotors. But, what if the runout exceeds the manufacturer’s specifications when the new rotor is installed on the vehicle? This is when it is permissible to machine a new rotor with an on-the-car brake lathe. This helps to match the rotors to the hub flange. Using an on-the-car lathe can help to reduce runout on new rotors. The main advantage of these lathes is that they are able to cut a rotor in its operating plane. This means that the rotor is machined to match the hub.

MYTH 3: Rotors do not need to be measured Even if you use new rotors, your chance of a pulsation comeback could be greater than if you left the old rotors on the vehicle. Runout in the hub and new rotor can stack up to cause Disc Thickness Variation (DTV) in a few thousand miles. DTV is the main cause of pulsation. Runout greater than .005� (¹.001 depending on the rotor or flange diameter) is a sign that the flange, rotor and/or bearing should be replaced. The needle of the dial indicator should be perpendicular to the rotor. Measurements should be taken


April 2013 |

Reader Service: Go to

Brake Lathe

a quarter inch from the edge. Flange runout can be corrected with tapered shims that are available to correct a runout of 0.003 inch (0.075 mm) to 0.009 inch (0.230 mm). A runout of more than 0.005 inch (0.125 mm) at the bearing flange cannot be corrected by the use of a shim. The combination of rotor and bearing flange could prevent the rotor from being turned. Checking bearing flange runout should be performed after friction surface runout. Changing the rotor position 180Âş on the bearing can check flange runout. If the high spot changes 180Âş, the rotor could be OK or ready to turn after the bearing is shimmed.

MYTH 4: Two passes make for a better finish Cutting a rotor in one pass is essential for productivity. For non-composite rotors, it is possible to take as much as 0.020" per side while still having an acceptable finish. However, with a composite rotor or one with hard spots, the depth should be reduced, likely below 0.010" per side, for a quality finish. In order to remove this much material, it is essential to have sharp bits. Cutting too fast will reduce the cut quality and possibly create chatter. A larger diameter rotor will need to turn slower than a small diameter one. Single-speed lathes are set at the slower speed of the largest application they are Go to

designed to cut. This is usually around 0.002" per revolution. Poor rotor finish can lead to noise. When machining a rotor, you have two primary goals: Provide a smooth surface finish for the pads and provide a true

surface finish. Never use the ballpoint pen measurement method when machining rotors. The only real way to measure is with a profilometer that measures the roughness average. It is very expensive and very fragile. The best way to make sure a lathe is cutting rotors the right way is to make sure your cutting bits are fresh, adapters are true and the crossfeed is set properly. â–

Tech Tips


Testing Ride Height Sensors



ome ride height sensor modules connect to the Controller Area Network (CAN) bus or other SAE or ISO bus or ride control module. The module can connect directly to the ABS/ESC module on a CAN bus or it can be part of the overall CAN Network in a loop that connects various modules in the vehicle. One way to test modules and ride height sensors on a high-speed CAN bus is with a scan tool. Most tools are able to look at the data directly. But, some scan tools may not be able to look at the datastream directly for a ride height sensor signal due to software issues with the tool. If you are in this situation, it is possible to observe how the actuation of a sensor, switch or component activation can change activity on the data bus. All CAN bus modules have power and two high-speed CAN wires. If you connect your scope between chassis ground and the bus wires in the OBDII DLC and look at voltage, it is possible to see packets of data being communicated on the bus as the sensor or vehicle height is changed. On a direct-type ride height CAN sensor, you can see the sensors communicating with ABS/ESC module as the sensor arm or vehicle is moved. It is impossible to tell what is being communicated, but it is possible to see they are communicating. This module is not a box, but part of the column. This module might have multiple can lines coming out of it. â– Reader Service: Go to

April 2013 |

» Spotlight


Working Together—The Federated Way Federated Auto Parts’ dedication to building profitable and successful relationships has made it one of the automotive aftermarket’s premier programmed distribution groups. Federated is devoted to providing professional technicians with superior customer service and name brand quality parts at competitive prices along with a full array of training and business support tools. Since Federated was established in 1985, the name has become synonymous with quality in the field of vehicle repair with over 8,000 stores and service centers nationwide. Federated Auto Parts stores are independently owned businesses that serve their local communities and are often family-owned and operated. These stores provide the highest quality replacement parts and accessories at competitive prices but also have the most knowledgeable people that can help with whatever the problem or challenge a customer may face. They also provide training and a host of other technical and marketing support programs including Federated Car Care, which identifies some of the best service providers in the country as being on the Federated team. Federated Auto Parts, headquartered in Staunton, Virginia, is one of the largest auto parts distribution and marketing organizations in North America. Federated is dedicated to supporting its customers with quality name brand parts, programs designed to grow their businesses, and experienced counter sales people who are knowledgeable in today’s evolving automotive technology. For more information, visit

Federated Auto Parts 508 Greenville Ave. Stauton, VA 24401 (540)885-8460 Reader Service: Go to



» Spotlight


ADVICS Original Equipment Quality Brake System Parts The best, brake engineering divisions of three companies were united to become one strong force… ADVICS. The ADVICS brand and brake system expertise was introduced more than a decade ago by combining the original equipment brake system engineering teams that have been in the automotive market since the 1960s. Sumitomo combined their engineering excellence with AISIN and Denso to create ADVICS – a brake parts supplier to which produces the best overall brake systems in the world.


Today, ADVICS designs and produces brake pads for original equipment manufacturers around the world. They also offer original equipment quality brake system parts to the automotive aftermarket. In North America, these aftermarket parts include:

The ADVICS original equipment engineering team manages the design and manufacturing of each part number offered in the Aftermarket. The engineering that goes into ADVICS ultra-premium brake pads has taken original ceramic

friction technology to the next level, resulting in increased stopping power and overall performance. For more information about ADVICS, please email:

ADVICS Reader Service: Go to


April 2013 |


Reader Service: Go to

Tech Tips

NISSAN This month is sponsored by:

Dual-Mass Flywheel Installation Errors APPLIES TO: 2003-’07 Nissan 350Z 3.5L / 2008-’12 Nissan 370Z 3.7L / 2002-’06 Nissan Altima, Maxima 3.5L 2005-’12 Nissan Xterra, Frontier 4.0L / 2003-’07 Infiniti G35 3.5L / 2008-’12 Infiniti G37 3.7L Today’s vehicles are becoming more and more complex to service, so proper procedures are very important to follow when making repairs. This is especially true when working on Infiniti and Nissan dual mass flywheels. The vehicles listed above have a crankshaft tone ring built into the flywheel. The dual mass flywheel is not indexed on the crankshaft and can be installed different ways. When installed incorrectly, the vehicle may not start, have a check Figure 1 engine light and the engine will not rev past 2,000 rpm. When removing a dual mass flywheel from the vehicles listed above, it’s recommended to make your own indexing marks on the flyFigure 2 wheel and crankshaft. When installing the new flywheel, transfer your marks from the old flywheel to the new flywheel to ease installation and assure proper indexing. If you’ve already removed the flywheel and did not make any indexing marks, follow this procedure for proper Figure 3 installation: 1. With the flywheel removed, look for the alignment dowel pinhole on the end of the crankshaft. 2. Find the same alignment dowel pinhole on the new flywheel. This can be done by finding the locating hole and notch on the front side of the flywheel (see Figure 2). 3. When you’ve located the notch and hole on the front side, flip the flywheel and find the same hole that goes all the way through the backside. Then look at Figures 1-3 and find the dowel pinhole. 4. When both have been located, align the two holes and torque the flywheel to the proper specifications. See Figures 1-3 to aid in locating the correct dowel pinholes. ■ Courtesy of Schaeffler Automotive Aftermarket Reader Service: Go to Manufacturer of LuK Clutches.


April 2013 |

Reader Service: Go to

Brought to you by:

Product Showcase

Centric Parts has announced the availability of a new line of C-Tek Ceramic Brake Pads. Like many of the premium Centric friction lines, C-Tek Ceramic Pads (103-Series) are positive molded, scorched and shimmed for optimal performance over the life of the product. Centric said it also has taken this opportunity to update the entire C-Tek Semi-Met program to include shims, where applicable. This updated C-Tek Brake Pad line also is debuting all-new packaging for the range, which reflects the shim and formula changes. For more information, visit or call 800-758-3004. Reader Service: Go to

With an estimated 60% of vehicles on the road in need of an alignment, Hunter Engineering Company developed the new Quick Check system to help shops quickly identify these vehicles and drive more traffic to the alignment bay. Quick Check captures toe and camber measurements and produces printed results in under a minute. Service writers can then use the easy-to-understand, colorcoded printouts to alert customers of misalignment issues and generate more repair orders for alignment service. Visit Reader Service: Go to

48 April 2013 |

Product Showcase Wearever celebrates 25 years of providing customers with quality brake pads and parts they can trust. Available exclusively from Advance Auto Parts Professional, the Wearever line includes Platinum, the best-performing ceramic brake pad; Gold, a quality OE replacement pad; Silver; and Frontline, for fleet vehicles. With billions of safe miles driven and no national recalls, you know the quality you get when choosing Wearever brake pads and parts. Wearever also features calipers, rotors, shoes/drums, wear sensors and hardware for your complete brake solution. For the latest promotions on Wearever products, visit or call your local Advance delivery store. Reader Service: Go to

NAPA Silver Oil Filters are the right choice for conventional oil change intervals. With 10 percent more cellulose filtering media, metal end caps to provide positive seal to prevent oil by-pass, an innovative combination by-pass and anti-drain back valve, and a coiled steel spring to prevent damage from pressure surges, you can't do better by your engine. Visit your local NAPA AUTO PARTS Store today for more information. Reader Service: Go to 49

Reader Service: Go to

It’s Fast, Easy and Accurate! Get FREE PRODUCT AND SERVICE INFO from the companies featured in this issue of Brake and Front End. >> VISIT and click on the company from which you want information. >> OR, go to and click on the Brake and Front End Rapid Response logo.



ACDelco Advance Auto Parts Professional ADVICS Akebono Corporation Auto Value/Bumper to Bumper AutoZone Bosch CARQUEST Auto Parts Centric Parts Chrysler Group LLC Federated Auto Parts Ford Parts Gabriel/Arvin Innovation Hunter Engineering Co. Jasper Engines & Transmissions Mitchell 1 NAPA Nucap Industries Nupla Corporation O'Reilly Auto Parts Packard Industries Parts Plus Permatex Inc Raybestos Chassis Red Kap Schaeffler Group USA SKF Tenneco/Monroe Brakes Tenneco/Walker Timken

18, 19 21 Cover 2, 44 29 Cover 4 34, 35 7 5 24, 25 13 16, 17, 43 15 41 23 47 1 Cover Card, 31 38, 44 26 40, 41 46 45 Cover 3 3, 22 37 8, 9 12 10 20, 33 28


Reader Service: Go to

Post your job for just $50 a month! Visit to get started today! Contact: Karen Kaim p) 330.670.1234 ext. 295 f ) 330.670.7153 51


Advertising Representatives The Tech Group Bobbie Adams 330-670-1234, ext. 238 Dean Martin 330-670-1234, ext. 225 Sean Donohue 330-670-1234, ext. 206

Why switch to PDQ? PRICES. Low prices. High Quality. Always. 1st time buyer? Order from this ad and receive these special prices.

Glenn Warner 330-670-1234, ext. 212 John Zick 949-756-8835 List Sales Manager Don Hemming 330-670-1234, ext. 286

Call now to order or to receive a free 2012 catalog 1-800-434-5141


Filters Mechatronics Kits Oils Hard Parts Manuals Torque Converters Audi • BMW Jaguar • Porsche Range Rover • VW

Authorized Distributor

ERIKSSON INDUSTRIES • 800-388-4418 Old Saybrook, CT • FAX 860-395-0047 •

52 April 2013 |

Classified Sales Tom Staab 330-670-1234, ext. 224



54 April 2013 |


Brake Lights

Customer came in with the complaint of a slight brake squeal when applying the brakes.

Do you have your own bad brakes story and pictures? If you do, it could be worth $75 and, if selected, your story could appear in BRAKE & FRONT END. Send digital pictures and your contact information to: Image courtesy of: Todd Bender, Angels Auto Care

GUESS THE CAR! WIN $50! #13 What vehicle MAKE uses the engine shown in the picture on the left? Submit your guess with our online contest form by visiting or scan the QR code to the right with your smart phone. The winner will be randomly selected from correct entries and awarded $50. Entries must be received by May 1, 2013.

Employees of Babcox Media, industry manufacturers and Brake and Front End advertisers are not eligible to enter.


April 2013 |

Reader Service: Go to

Reader Service: Go to

Brake & Front End  
Brake & Front End  

Brake & Front End delivers application-specific undercar technical information and diagnostic strategies for even the most advanced vehicles...