6000 V6-191 3.1L (1989)
Brake Bleeding: Service and Repair
Hydraulic System Bleeding
With ABS System
Manual Bleeding
The front hydraulic circuits may be manually bled in the same manner as conventional brakes. The rear brakes must be pressure bled according to the
following procedure.
Pressure Bleeding
Only the rear brakes must be pressure bled. Front hydraulic circuits may be bled manually. To prevent air, moisture and other contaminants from
entering system, only diaphragm type pressure bleeding equipment should be used.
Front Circuit
1.
Disconnect battery ground cable, then depressurize hydraulic accumulator. Refer to DEPRESSURIZING HYDRAULIC SYSTEM.
2.
Disconnect fluid level sensor electrical connector, then remove sensor.
3.
Install brake bleeder adapter tool No. J-35798 or equivalent, in place of sensor.
4.
Attach diaphragm type brake bleeder tool No. J 29532 or equivalent, to fluid reservoir, then charge to 20 psi.
5.
Raise and support vehicle. Attach a clear bleeder hose to a front bleeder valve, then submerse the other end in a clear container partially filled with
DOT 3 brake fluid.
6.
Open bleeder valve, using brake bleeder wrench tool No. J 21472 or equivalent open end wrench, then allow fluid to flow from bleeder until no air
is seen in brake fluid.
7.
Close bleeder valve, ensuring bleeder seats in the closed position.
8.
Repeat steps 5 through 7 on remaining front bleeder valve.
9.
Check fluid level and adjust as required.
10.
Check pedal for sponginess. Repeat procedure until desired pedal is achieved.
11.
Remove bleeding equipment, then install fluid level sensor.
12.
Reactivate Delco-Loc radios by turning ignition and radio to the On position, then pressing the Mute button on the steering wheel
control.
Rear Circuit
Fill brake fluid reservoir with DOT 3 brake fluid. Keep reservoir at least half full during procedure.
1.
Turn ignition switch to On position and allow system to charge. Pump motor will stop when system is charged.
2.
Raise and support vehicle. Attach a clear bleeder hose to rear bleeder valve, then submerse the other end in a clear container partially filled with
DOT 3 brake fluid.
3.
Open bleeder valve using brake bleeder wrench tool No. J 21472 or equivalent open end wrench, then with ignition switch in On position, depress
brake pedal for at least 10 seconds. Do not allow pump to run more than 60 seconds at a time. If pump must be run longer than 60 seconds,
allow pump to cool between 60 second runs.
4.
Allow fluid to flow from bleeder until no air is seen in brake fluid. Repeat step 3 if necessary.
5.
Close bleeder valve, then repeat steps 2 through 4 on remaining rear bleeder valve.
6.
Lower vehicle. Check reservoir fluid level and adjust as required.
7.
Check pedal for sponginess. If condition exists, repeat procedure until desired pedal is achieved. Do not move vehicle until a firm brake pedal is
achieved.
Without ABS System
Manual Bleeding
Pressure bleeding is recommended for all non-ABS hydraulic systems. However, if a pressure bleeder is unavailable, use the following procedure.
Brake fluid damages painted surfaces. Immediately clean any spilled fluid.
1.
Remove vacuum reserve by pumping brakes several times with engine off.
2.
Fill master cylinder reservoir with clean brake fluid. Check fluid level often during bleeding procedure; do not let reservoir fall below half full.
3.
If necessary, bleed master cylinder as follows:
a. Disconnect master cylinder forward brake line connection until fluid flows from reservoir. Reconnect and tighten brake line.
b. Instruct an assistant to slowly depress brake pedal one time and hold.
c. Crack open front brake line connection again, purging air from cylinder.
d. Retighten connection and slowly release brake pedal.
e. Wait 15 seconds, then repeat until all air is purged.
f.
Bleed the rearward (nearest the cowl) brake line connection by repeating steps a through e.
4.
Loosen, then slightly retighten bleeder valves at all four wheels. Repair any broken, stripped or frozen valves at this time.
5.
Proceed to appropriate wheel first and follow set sequence according to the bleeding sequence.
Bleeding Sequence: RR-LF-LR-RF
