Page 1

BR–16 BRAKE SYSTEM

BRAKE BOOSTER

BRAKE BOOSTER BRAKE BOOSTER REMOVAL

1. REMOVE MASTER CYLINDER (See page BR–10) 2. DISCONNECT VACUUM HOSE FROM BRAKE BOO– STER 3. REMOVE PEDAL RETURN SPRING 4. REMOVE CLIP AND CLEVIS PIN

5. REMOVE BRAKE BOOSTER, GASKET AND CLEVIS


BR–17 BRAKE SYSTEM

BRAKE BOOSTER

l

BRAKE BOOSTER INSTALLATION 1. ADJUST LENGTH OF BOOSTER PUSH ROD (a) Install the gasket on the master cylinder. (b) Set the SST on the gasket, and lower the pin until its tip slightly touches the piston. SST 09737–00010

(c) Turn the SST upside down, and set it on the booster. SST 09737–00010 (d) Measure the clearance between the booster push rod and pin head (SST). Clearance: 0 mm (0 in.) (e) Adjust the booster push rod length until the push rod lightly touches the pin head.

2. INSTALL BRAKE BOOSTER, GASKET AND CLEVIS (a) Install the booster and gasket. (b) Install the clevis. (c) Install and torque the booster mounting nuts. Torque: 13 N–m (130 kgf–cm, 9 ft–lbf) 3. CONNECT CLEVIS TO BRAKE PEDAL Insert the clevis pin into the clevis and brake pedal and install the clip to the clevis pin. 4. INSTALL PEDAL RETURN SPRING 5. INSTALL MASTER CYLINDER (See page BR–15) 6. CONNECT VACUUM HOSE TO BRAKE BOOSTER 7. FILL BRAKE RESERVOIR WITH BRAKE FLUID AND BLEED BRAKE SYSTEM (See page BR–8) 8. CHECK FOR FLUID LEAKAGE 9. CHECK AND ADJUST BRAKE PEDAL (See page BR–7) 10. DO OPERATIONAL CHECK (See page BR–8)


BR–7 BRAKE SYSTEM

CHECK AND ADJUSTMENT

CHECK AND ADJUSTMENT BRAKE PEDAL CHECK AND ADJUSTMENT 1. CHECK PEDAL HEIGHT Pedal height from asphalt sheet: 140–150 mm (5.51–5.91 in.) 2. IF NECESSARY, ADJUST PEDAL HEIGHT (a) Disconnect the connector from the stop light switch. (b) Loosen the stop light switch lock nut and remove the stop light switch. (c) Loosen the push rod lock nut. (d) Adjust the pedal height by turning the pedal push rod. (e) Tighten the push rod lock nut. Torque: 25 N–m (260 kgf–cm, 19 ft–lbf) (f) Install the stop light switch and turn it until it lightly contacts the pedal stopper. (g) Turn the stop light switch back one turn. (h) Check the clearance (A) between stop light switch and pedal. Clearance: 0.5–2.4 mm (0.02–0.09 in.) (i) Tighten the stop light switch lock nut. (j) Check the stop lights come on when the brake pedal is depressed, and go off when the brake pedal is released. (k) After adjusting the pedal height, check the pedal free play. HINT: If clearance (A) between the stop light switch and the pedal stopper has been adjusted correctly, the pedal freeplay will meet the specifications. 3. CHECK PEDAL FREEPLAY (a) Stop the engine and depress the brake pedal several times until there is no more vacuum left in the boost– er. (b) Push in the pedal by hand until the beginning of the second resistance is felt. Measure the distance, as shown. Pedal freeplay: 3–6 mm (0.12–0.24 in.) If incorrect, check the stop light switch clearance. If the clearance is OK, then troubleshoot the brake system. HINT: The freeplay to the 1 st resistance is due to the play between the clevis and pin. This is magnified up to 1–3 mm (0.04–0.12 in.) at the pedal.


BR–8 BRAKE SYSTEM

CHECK AND ADJUSTMENT

4. CHECK PEDAL RESERVE DISTANCE Release the parking brake. With engine running, depress the pedal and measure the pedal reserve distance, as shown. Pedal reserve distance from asphalt sheet at 490 N (50 kgf, 110.2 lbf): w/o 4–Wheel ABS: More than 65 mm (2.56 in.) w/ 4–Wheel ABS: More than 70 mm (2.76 in.) If incorrect, troubleshoot the brake system.

BRAKE BOOSTER OPERATIONAL TEST 1. OPERATING CHECK (a) Depress the brake pedal several times with the engine oft, and check that there is no change in the pedal reserve distance. (b) Depress the brake pedal and start engine. If the pedal goes down slightly, operation is normal.

2. AIR TIGHTNESS CHECK (a) Start the engine and stop it after 1 or 2 minutes. Depress the brake pedal several times slowly. If the pedal goes down furthest the 1 st time, but gradually rises after the 2nd or 3rd time, the booster is air tight. (b) Depress the brake pedal while the engine is running, and stop it with the pedal depressed. If there is no change in pedal reserve travel after holding the pedal for 30 seconds, the booster is air tight.

BRAKE SYSTEM BLEEDING HINT: If any work is done on the brake system or if air is suspected in the brake lines, bleed the system of air NOTICE: Do not lot broke fluid remain on a painted surface. Wash it off immediately. 1. FILL BRAKE RESERVOIR WITH BRAKE FLUID Check the fluid level in the reservoir after bleeding each wheel. Add fluid, if necessary. Fluid: SAE J1703 or FMVSS No. 116 DOT 3 2. BLEED MASTER CYLINDER HINT: If the master cylinder was disassembled orthe reservoir becomes empty, bleed the air from the master cylinder. (a) Disconnect the brake lines from the master cylinder. (b) Slowly depress the brake pedal and hold it.


BR–9 BRAKE SYSTEM

CHECK AND ADJUSTMENT

(c) Block oft the outlet plug with your finger, and release the brake pedal. (d) Repeat (b) and (c) 3 or 4 times.

3. CONNECT VINYL TUBE TO WHEEL CYLINDER BLE– EDER PLUG Insert other end of the tube in a half–full container of brake fluid. HINT: Begin air bleeding from the wheel cylinder with the longest hydraulic line. 4. BLEED BRAKE LINE (a) Slowly depress the brake pedal several times. (b) While an assistant depresses the pedal, loosen the bleeder plug until fluid starts to run out. Then close the bleeder plug. (c) Repeat this procedure until there are no more air bubbles in the fluid. Bleeder plug tightening torque: 11 N–m (110 kgf–cm, 8 ft–lbf) 5. REPEAT PROCEDURE FOR EACH WHEEL 6. BLEED LSP & BV

PARKING BRAKE CHECK AND ADJUSTMENT 1. CHECK PARKING BRAKE LEVER TRAVEL Pull the parking brake level all the way up, and count the number of clicks. Parking broke lover travel at 196 N (20 kgf, 44.1 lbf): 13–19 clicks

2. IF NECESSARY, ADJUST PARKING BRAKE HINT: Before adjusting the parking brake, make sure that the rear brake shoe clearance has been adjusted. (a) Loosen the lock nut and turn the adjusting nut until the travel is correct. (b) Then tighten the lock nut. Torque: 13 N–m (130 kgf–cm, 9 ft–lbf) (c) After adjusting the parking brake, confirm that the rear brakes are not dragging.


BR–2 BRAKE SYSTEM

–

DESCRIPTION

GENERAL DESCRIPTION 1. Care must be taken to replace each part properly a: it could affect the performance of the brake system and result in a driving hazard. Replace the parts with parts of the same part number or equivalent. 2. It is very important to keep parts and the area clean when repairing the brake system. 3. If the vehicle is equipped with a mobile communication system, refer to the precaution in the IN section.

DESCRIPTION The service brakes consist of a foot brake which changes rotational energy to thermal energy to stop the vehicle while it is being driven and a parking brake to keep the vehicle from moving while it is parked.

OPERATION FOOT BRAKE When the brake pedal is depressed, a vacuum builds up in the booster which amplifies the pedal force, pressing on the piston in the master cylinder. The piston movement raises the hydraulic pressure in the cylinder. This hydraulic pressure is then applied to each respective brake cylinder and wheel cylinder, and acts to press the brake pads and shoes against the rotating discs and drums. The resulting friction converts the rotational energy to thermal energy, stopping the vehicle.


BR–18 BRAKE SYSTEM

FRONT BRAKE

FRONT BRAKE COMPONENTS

BRAKE PADS REPLACEMENT HINT: If a squealing noise occurs from the brakes while driving, check the pad wear indicator plate. If the pad wear indicator plate contacts the disc, the brake pads should be replaced. 1. REMOVE FRONT WHEEL

2. INSPECT PAD LINING THICKNESS Check the pad thickness and replace pads if not within specification. Minimum thickness: 1.0 mm (0.039 in.)


Thank you very much for your reading. Please Click Here. Then Get COMPLETE MANUAL. NO WAITING

NOTE: If there is no response to click on the link above, please download the PDF document first and then click on it.


BR–19 BRAKE SYSTEM

FRONT BRAKE

3. REMOVE THESE PARTS: (a) Clip (b) 2 pins (c) Anti–rattle spring (d) 2 pads (e) 4 anti–squeal shims NOTICE: The anti–rattle springs and clips can be used again provided that they have sufficient rebound, no deformation, cracks or wear, and have had all rust, dirt and foreign particles cleaned off. 4. CHECK DISC THICKNESS AND RUNOUT (See page BR–22)

6. INSTALL NEW PADS NOTICE: When replacing worn pads, the anti–squeal shims must be replaced together with the pads. (a) Draw out a small amount of brake fluid from the reservoir. (b) Press in the pistons with a hammer handle or equivalent. HINT: • Always change the pads on one wheel at a time as there is a possibility of the opposite piston flying out. • If the piston is difficult to push in, loosen the bleeder plug and push in the piston while letting some brake fluid escape.

(c) Install the 4 anti – squeal shims to new pads, as shown. HINT: Apply disc brake grease to both side of the inner anti–squeal shim. (d) Install the 2 pads. NOTICE: Do not allow oil or grease to got on the rubbing face.

Profile for 1634853

1991 Toyota 4Runner Service Repair Manual  

1991 Toyota 4Runner Service Repair Manual  

Profile for 1634853
Advertisement