Tahoe 4WD V8-393 6.5L DSL Turbo VIN S (1995)
Fig. 4 Spool valve inspection
CLEANING/INSPECTION
1.
Clean all parts in a suitable solvent being careful to avoid losing small parts.
2.
Inspect valve spool and valve spool bore in booster housing for corrosion, nicks, scoring or other damage. Discoloration of the spool or bore,
particularly in the grooves, is not harmful.
3.
If the valve spool or the spool bore has nicks or scoring that can be felt with a fingernail, particularly on the hands, the spool and housing should
be replaced as an assembly, Fig. 4. The clearance between the valve spool and the spool bore of the housing is important. Because of this,
the spool and housing make are made as a selective assembly and therefore can only be replaced as an assembly.
4.
Inspect the input rod and piston assembly for corrosion, nicks, scoring or excessive wear. If the piston is damaged, the input rod and piston
assembly should be replaced.
5.
Inspect piston bore in booster housing for corrosion, nicks, scoring or other damage. If the bore is damaged, the valve spool and housing should be
replaced as an assembly.
ASSEMBLY
Lubricate all the seals and metal friction points with power steering fluid.
1.
Install return line seal, then the fitting Fig. 3.
2.
Install accumulator valve and spool valve into housing.
3.
Install seal on piston assembly using seal protector tool No. J-25083 or equivalent.
4.
Install seal onto the housing, then install cover and bolts. Torque housing bolts to 22 ft. lbs.
5.
Install bracket and nut, then torque to 110 ft. lbs.
6.
Install boot, output pushrod, baffle, piston return spring, and retainer using seal protector tool No. 2455l or equivalent.
7.
Install retainer, spring, O-ring, and plug, using accumulator compressor tool No. J-26889 or equivalent, and C-clamp.
8.
Depress the accumulator, then install the retainer and remove C-clamp.
9.
Jam nut from the repair kit onto pedal rod, and install eyelet onto pedal rod.
10.
Adjust eyelet to required length.
Power Brake Unit, Remove
Pump brake pedal several times with engine off to deplete accumulator of fluid.
1. Remove two nuts attaching master cylinder to booster, then move master cylinder away from booster with brake lines attached.
2. Remove hydraulic lines from booster. Plug and cap all lines and outlets.
3. Remove retainer and washer securing booster pushrod to brake pedal arm.
4. Remove nuts attaching booster unit to dash panel.
5. Loosen booster from dash panel and move booster pushrod inboard until it disconnects from brake pedal arm. Remove spring washer from brake
pedal arm.
6. Remove booster unit from vehicle.
7. Reverse procedure to install. To fill the Hydro-Boost system, proceed as follows:
The power steering fluid and brake fluid cannot be intermixed. If the brake seals contact power steering fluid or steering seals contact brake
fluid, seal damage will result.
a. Fill power steering pump reservoir to the proper level and allow fluid to remain undisturbed for at least two minutes.
b. Start and operate engine momentarily. Add fluid, if necessary.
