DIAGNOSINGAND FIXING BRAKE CALIPER ISSUES
At our Car Repair Shop Astoria, some customers come in with brake issues or brake problems are diagnosed during New York State inspection or working on something else on the car. One of the problems found is with the Brake Calipers.
What is a Brake Caliper?
A brake caliper is a component of disc brake systems (used in most modern vehicles). Its job is to squeeze the brake pads against the rotor (disc) to create friction, which slows the wheel down. It is very much like a bicycle hand brake when you pull the lever, the pads pinch the wheel rim. In cars, the caliper does the pinching, and the rotor is like the rim.
What are the main parts of a Brake Caliper?
There are several parts or components to a brake caliper. Let’s examine them. First there are Pistons, which are cylindrical components inside the caliper that are pushed by brake fluid. They press the pads against the rotor and can be single-piston, dual-piston, or multi-piston (up to 6 or more in high-performance cars).
Next are Brake Pads which are mounted inside the caliper on either side of the rotor. They are the actual surfaces that make contact with the rotor.
The Caliper Bracket mounts the caliper to the suspension or steering knuckle and holds it in the correct position.
Guide Pins / Slides let the caliper move laterally so it can center itself over the rotor as it wears.
Dust Boots and Seals protect pistons from road grime, water, and rust. They are essential for long life and reliable operation.
Common Brake Caliper Problems and how to fix them
Here are some of the issues that can arise with your brake calipers, their symptoms, and how to fix them.
A sticking Caliper - There can be a sticking Caliper which occurs when one side of the brakes stays engaged, even after you release the pedal. Symptoms of this are when the car pulls to one side when braking, Excessive heat or burning smell from one wheel, Uneven brake pad wear, decreased fuel efficiency (dragging brakes), vibration or noise during driving (even without braking).
This can be caused by a sticking piston brought on by rust, debris or dried up seals. Dirty or corroded guide pins, damaged or dry slide pin boots and brake fluid contamination.
To fix, remove caliper and inspect pads and piston. Clean and lubricate guide pins using high-temp brake grease. If piston is sticking, then try compressing it back with a C-clamp. If it resists, it may be corroded inside. If the piston is seized or doesn’t move smoothly, you can rebuild the caliper or replace it with a remanufactured caliper. Lastly flush the brake fluid (moisture causes internal rust). It is recommended to have a professional mechanic like our shop for Brake Service in Astoria.
Seized Pistons. Corrosion or old brake fluid can cause pistons to get stuck which leads to braking inefficiency or complete failure on one wheel. You’ll know if this is the case if you get constant braking on one wheel (drag), smoke or excessive heat from wheel, brake pad wears very quickly, soft brake pedal feel, wheel may become extremely hot to the touch
To fix, remove the caliper and check piston movement. A typical Rebuild kit costs $10–20 and includes seals, boot, and lube. Carefully remove the piston (use compressed air or a brake caliper tool) and clean the bore with brake cleaner and light emery cloth. Reinstall new seals and piston. Or just replace the caliper if too corroded or you're short on time.
Leaking Calipers occur when brake fluid leaks from the piston seals. This is dangerous, as you’ll lose braking pressure. Symptoms of leaking calipers are brake fluid on the wheel, tire, or ground, spongy brake pedal, brake warning light and the aforementioned loss of braking pressure.
To fix – if the seal is leaking rebuild the caliper with new seals, check hose and banjo bolt washers (copper crush washers may need replacing). If housing is cracked, replace the caliper
Uneven brake pad wear is when one pad is more worn than the other can indicate sticking pins or piston problems. Symptoms of this are one pad significantly thinner than the other on the same caliper, noisy braking (squealing or grinding), and rotor scoring or hot spots
To fix, clean and lube guide pins, check pins for scoring or wear and replace if needed. Ensure pads move freely in the bracket (clean and file down rust) and inspect piston movement. Replace hardware (springs, clips, shims) if
corroded or bent.
As you can see, the fixes for these issues are not for amateurs, nor will you be able to complete them if you do not have the correct tools. A professional mechanic like the professional Auto Mechanic in Astoria.
Caliper Bracket Issues
If you experience clicking or clunking when braking, uneven pad contact, pads not sitting squarely or brake pad binding, then there may be issues with your Caliper Bracket.
This is caused by worn or damaged bracket, missing or incorrect hardware, debris or buildup preventing pad movement
To fix this, clean bracket channels thoroughly and use brake-specific antiseize on pad contact points. Replace the bracket if it's cracked or threads are stripped
Frozen Slide Pins
The symptoms of frozen slide pins are when the outer pad doesn’t wear evenly, the Caliper won’t center itself or difficulty installing or removing caliper
To fix this, remove slide pins, clean with brake cleaner and wire brush, inspect for pitting replace if too rough, use synthetic high-temp brake grease and replace the rubber boots if torn or dry
To prevent issues with your brake calipers, follow the recommended maintenance schedule for your vehicle and flush the brake fluid as recommended. Remember that moisture leads to internal rust and seal damage. Check the caliper condition every time you replace pads or rotors and avoid cheap remanufactured calipers some are poor quality. Don’t ignore small pulling or vibration issues they often start in the caliper.
Most of the fixes mentioned require a professional mechanic. If you are in the NYC area, then see our Auto Mechanic Queens.