Suburban 3/4 Ton 4WD V8-305 5.0L (1986)
Hydraulic Brake Booster: Service and Repair
Power Brake Unit Replace
SERIES 10---30/1500---3500
Before disconnecting lines from power unit, depress and release brake pedal several times to allow pressure to discharge from accumulator.
1.
On P30 motor home, raise and support vehicle, if necessary.
2.
On all vehicles, remove master cylinder to power brake unit attaching nuts, then position master cylinder aside. Do not disconnect brake lines from
master cylinder.
3.
Disconnect hydraulic lines from power brake unit. Plug all lines and ports to prevent fluid loss and dirt entry.
4.
On all models except P30 motor home, remove pedal pushrod cotter pin and washer, then disconnect pushrod from brake pedal or pivot lever.
Lower steering column or remove support brackets as necessary. Remove power brake unit bracket to dash panel or support bracket attaching nuts,
then the power brake unit.
5.
On P30 motor home, remove operating lever to vertical brake rod cotter pin, nut, bolt and washers. Remove power brake unit linkage bracket to
front and rear support bracket attaching nuts, washers and bolts, then remove power brake unit from vehicle. Remove operating lever to pedal rod
cotter pin, nut, washer and bolt. Remove brake pedal rod lever nut and bolt, then the lever, sleeve and bushing.
6.
Reverse procedure to install, then bleed hydraulic system as follows:
a. Fill power steering reservoir to proper level and allow vehicle to sit for approximately two minutes.
b. Start engine and allow to run for several minutes, then shut engine off. Correct fluid level as necessary. Do this several times until fluid level
becomes constant.
c. Raise and support front of vehicle, then turn wheels lock to lock. Shut engine off and add fluid as necessary.
d. Lower vehicle, then start engine and depress brake pedal several times while turning steering wheel lock to lock.
e. Shut engine off, then depress brake pedal 4 to 5 times to allow accumulator to deplete.
f.
Check reservoir and refill as required. If fluid is extremely foamy, allow vehicle to sit for several minutes, then repeat procedure above.
