G 20 Van V6-262 4.3L VIN Z (1993)
Brake Bleeding: Service and Repair
Hydraulic System Bleeding
Manual Bleeding
Before bleeding the brakes, the front and rear displacement cylinder pistons must be returned to the top most position. Using a TECH 1 or equivalent
scan tool, enter manual control function and ``Apply'' the front and rear motors. Ensure enable relay is on.
Use only Dot 3 brake fluid from a clean and sealed container. Do not use Dot 5 brake fluid.
1.
Ensure brake fluid reservoir is properly filled.
2.
Attach bleeder hose to modulator assembly rearward bleed valve, submerge other end of hose into clean container partially filled with brake fluid.
3.
Pump brake pedal several times, then slowly open bleeder valve 1/2 to 3/4 turns.
4.
Depress brake pedal and hold until fluid begins to flow.
5.
Close valve and repeat steps 3 and 4 on forward valve. Once fluid is seen to flow from both the forward and rearward valves, modulator valve and
master cylinder are filled sufficiently filled with fluid. However, modulator and master cylinder assemblies may not be purged of air. At this point,
bleed the wheel brakes.
6.
Raise and support vehicle.
7.
Attach bleeder hose to bleeder valve of right rear wheel, submerge other end of hose into clean container partially filled with brake fluid.
8.
Open bleeder valve and slowly depress brake pedal, close valve and slowly release brake pedal, wait five seconds.
9.
Repeat step 8, until brake pedal feels firm and no air bubbles are observed in bleeder hose.
10.
Repeat steps 7, 8 and 9, first for left rear wheel, then the right front caliper, then the left front caliper.
11.
Lower vehicle and attach bleeder hose to rearward bleeder valve.
12.
Depress brake pedal using moderate pressure, then slowly open bleeder valve 1/2 to 3/4 turns and allow fluid to flow.
13.
Close valve and release brake pedal, wait five seconds.
14.
Repeat steps 12 and 13, until all air is purged from system.
15.
Repeat steps 11, 12, 13 and 14, on forward bleeder valve.
16.
Road test vehicle, to verify brake performance.
Pressure Bleeding
Before bleeding the brakes, the front and rear displacement cylinder pistons must be returned to the top most position. Using a TECH 1 or equivalent
scan tool, enter manual control function and ``Apply'' the front and rear motors. Ensure enable relay is on.
Use only Dot 3 brake fluid from a clean and sealed container. Do not use Dot 5 brake fluid.
1.
Remove master cylinder cover, ensure reservoir is properly filled.
2.
Connect bleeder adapter tool J 35589 or equivalent to master cylinder reservoir.
3.
Connect bleeder adapter to pressure bleeding equipment.
4.
Connect a clear plastic bleeder hose to modulator assembly rearward bleeder valve, submerge other end of hose into clean container partially filled
with brake fluid.
5.
Adjust pressure bleeding equipment to 5-10 psi, then wait for approximately 30 seconds to insure there is no leakage.
6.
Adjust pressure bleed equipment to 30-35 psi.
7.
To bleed ABS hydraulic modulator and master cylinder, proceed as follows:
a.
Slowly open rearward bleeder valve and allow fluid to flow until no air is seen in fluid, then torque valve to 65 inch lbs..
b.
Attach bleeder hose to modulator assembly forward bleeder hose.
c.
Slowly open forward bleeder valve and allow fluid to flow until no air is seen in fluid, then torque valve to 65 inch lbs..
8.
To bleed brake pipe to modulator assembly connections, proceed as follows:
a.
Place a shop cloth between brake pipe connections and the top of the motor pack assembly.
b.
Loosen forward most brake pipe nut and check for air escaping in fluid.
c.
When air flow ceases, torque brake pipe nut to 24 ft. lbs..
d.
Repeat steps b and c for remaining three brake pipe connections, moving from front to rear.
9.
To bleed wheel brakes, proceed as follows:
a.
Raise and support vehicle.
b.
Attach bleeder hose to bleeder valve of right rear wheel, submerge other end of hose into clean container partially filled with brake fluid.
c.
Loosen bleeder valve and allow fluid to flow, close valve when fluid begins to flow without any air bubbles.
d.
Repeat steps b and c, first for left rear wheel, then the right front caliper, then the left front caliper.
10.
Road test vehicle, to verify brake performance.
Without ABS System
Manual Bleeding
1.
If vehicle is equipped with power brakes, remove vacuum reserve by applying brakes several times with engine off.
2.
Fill master cylinder reservoirs with suitable brake fluid. Be sure to always keep master cylinder reservoirs at least half full during entire
bleeding procedure.
