Brakes - Updated Bleeding Procedure

BRAKES
BR004-97

Date:
March 7, 1997

Title:
1997 PREVIA BRAKE SYSTEM BLEEDING

Models:
'97 Previa

REVISION NOTICE:

The information contained in this TSB updates BR003-96 dated November 22, 1996.

Introduction








A new style master cylinder with an integrated Proportioning and By-pass valve, has been introduced on the 1997 Previa, which requires different brake system bleeding procedures

NOTE:
The LE Previa no longer has a separate Load Sensing Proportioning & By-pass Valve, it is now integrated into the master cylinder.

Production Change Information

^ 1997 Previas starting with VINs: JT3GK * * M * V1246621
JT3HK * * M * V1066784

Brake System Bleeding Procedures

^ Use the following procedures for bleeding BOTH brake systems.

^ Bleed the system of air when any work is done on the brake system or if air is suspected in the brake lines.

CAUTION:
Do not let brake fluid remain on any painted surfaces. Wash off immediately.





1. Fill brake reservoir with brake fluid. Check the reservoir after bleeding each wheel. Add fluid if necessary.

Fluid: SAE J1703 or FMVSS No. 116 DOT3

2. Bleed the master cylinder.

NOTE:
If the master cylinder was disassembled or if the reservoir becomes empty, bleed the air from the master cylinder.

a) Disconnect the brake lines from the master cylinder. Use a container to catch the brake fluid.





b) Slowly depress the brake pedal and hold it.





c) Block off the outlet holes with your fingers, and release the brake pedal.

d) Repeat steps (b) and (c) 3 or 4 times.

e) Connect the brake lines to the master cylinder.





3. Begin bleeding air from the REAR brake caliper or wheel cylinder with the longest hydraulic line.

Connect the vinyl tube to rear caliper or wheel cylinder bleeder plug. Insert other end of the tube in a half-full container of brake fluid.

4. Bleed air from brake line.

NOTE:
Bleed the rear brake of air FIRST if the front brake is bled of air first the rear brake cannot be bled.





a) Slowly pump the brake pedal several times.

b) While an assistant presses on 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 air bubbles in the fluid.





5. Bleed the load sensing proportioning and By-pass valve (vehicles without ABS).





6. Bleed the front calipers, starting with the calipers with the longest hydraulic line.