Hummer H1 (2002+). Manual - part 127

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 Steering System  8-15

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05745159

POWER STEERING PUMP AND PULLEY 
REPLACEMENT 

Removal

1.

Disconnect return lines and high pressure line from back 
of pump (Figure 8-24).

2.

Remove serpentine belt from power steering pump pulley.

3.

Using puller J–25034-C or equivalent, remove pulley from
pump.

4.

Remove three bolts going through bracket into front of
pump (Figure 8-24).

Installation

1.

Apply non-hardening thread sealant to studs on back of 
pump and secure support bracket with two nuts. Tighten 
nuts to 45 lb-ft (61 N•m) (Figure 8-24)

2.

Maneuver pump into position behind power steering
bracket.

3.

Secure pump to mounting bracket with three bolts.

4.

Secure support bracket to block with bolt.

5.

Connect two return lines to power steering pump
(Figure 8-24).

6.

Check condition of O-ring seal and connect high pressure
line to back of pump.

CAUTION: In step 7, do not attempt to drive the pulley onto
the pump shaft with a hammer. The pulley and pump ring will
be damaged. 

7.

Press pulley onto pump using pulley installer J–25033-C
or equivalent. Pulley should be flush +/- 0.25 mm (0.010
inch) with the end of the power steering pump shaft. 

8.

Purge air from power steering system.

9.

Start engine and check for leaks.

Figure 8-24:   Power Steering Pump Mounting 

MOUNTING BRACKET

PULLEY

POWER STEERING

SUPPORT BRACKET

POWER

STEERING

PUMP

POWER STEERING

FLUID RESERVOIR

4-1-00

8-16

Steering System

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POWER STEERING HYDRAULIC SYSTEM 
PRESSURE AND RETURN HOSE REPLACEMENT

NOTE: Removal and installation procedures are basically the
same for all hydraulic system pressure and return hoses. This
procedure covers the power steering pump to hydro-boost re-
turn hose and the steering gear to hydro-boost pressure hose.

Removal 

1.

Disconnect return hose from power steering pump and 
hydro-boost (Figures 8-25 and 8-26).

2.

Remove locknut, washer, bolt, and two clamps from
control valve hose and return hose. (Figure 8-25).

3.

Remove locknut, two washers, and bolt securing two
clamps and harness clamp to power steering line bracket.

4.

Disconnect pressure hose from hydro-boost and steering
gear and remove pressure hose. Remove two O-ring seals
from pressure hose. Check condition of O-ring seals and
replace if necessary  (Figures 8-25 and 8-26).

Installation 

1.

Connect pressure hose to steering gear and hydro-boost 
(Figure 8-26).

2.

Connect return hose to power steering pump and hydro-
boost with two clamps  (Figures 8-25 and 8-26).

3.

Install two clamps on return hose and control valve hose.
Secure return hose, control valve hose, and two clamps
together with bolt, washer, and locknut (Figure 8-25).

4.

Install harness clamp and two clamps on power steering
lines bracket with bolt, two washers, and locknut.

5.

Purge air from power steering system. Refer to  (See “Purging
Air From the Power Steering System” on page 8-22) .

Figure 8-25:   Power Steering Hose Replacement at 

Brake Hydro-Boost

Figure 8-26:   Power Steering Hose 

Replacement at Steering Gear

POWER STEERING FLUID RESERVOIR REPLACE-
MENT

Removal

1.

Suction the power steering fluid from the reservoir.

2.

Loosen the hose clamp and disconnect the power steering
pump supply line from the reservoir (Figure 8-27).

3.

Remove the two bolts and washers securing the reservoir
to the bracket and remove the reservoir.

Installation

1.

Installation is the reverse of the removal procedure.

Figure 8-27:   Reservoir Replacement

PRESSURE

HYDRO-BOOST

O-RING SEALS

RETURN HOSE

 HOSE

PRESSURE HOSE

STEERING 

O-RING SEALS

GEAR

RESERVOIR

SUPPLY LINE

 4-1-00

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 Steering System  8-17

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05745159

POWER STEERING COOLER AND COOLER 
HOSE REPLACEMENT 

Removal

1.

Disconnect two hoses from cooler (Figure 8-28).

2.

Remove cooling fan for access into fan shroud.

3.

Remove two nuts, four washers, reinforcement plate, two
bolts, and cooler.

4.

Disconnect hose at power steering gear and hose at back
of pump.

5.

Remove P-clamps holding hoses together and remove
hoses.

Figure 8-28:   Power Steering Cooler and 

Cooler Hoses 

Installation

1.

Secure power steering oil cooler to fan shroud with two 
bolts, reinforcement plate, four washers, and two nuts 
(Figure 8-28).

2.

Reinstall cooling fan.

3.

Connect hoses to cooler and secure with clamps

4.

Connect other end of each hose to its respective location at
steering gear or pump and secure with clamps.

5.

Secure hoses together with P-clamps.

6.

Purge air from system.

REINFORCEMENT PLATE

POWER

STEERING

COOLER

HOSE

POWER

STEERING

GEAR

POWER

STEERING

PUMP

4-1-00

8-18

Steering System

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POWER STEERING GEAR SERVICE 

The Saginaw recirculating ball, power steering gear
(Figure 8-29), is a fully serviceable component. The gear can
be adjusted, or overhauled as needed. Overhaul requires that
the gear be removed from the vehicle as repair can only be per-
formed on the bench.

The steering gear adjustments described in the overhaul section
can be performed on the bench or in the vehicle. Refer to the
adjustment section for details.

Figure 8-29:   Power Steering Gear Cross Section

GEAR 

BALL 

THRUST

O-RING

FLUID 

FLUID 

HOSE 

SEAL

STUB 

ADJUSTER

TEFLON 

SPOOL

VALVE

STUB 

WORMSHAFT

SHAFT

RACK

TEFLON

END 

HOUSING

GUIDE

BEARING

 SEAL

INLET

OUTLET

FITTING 

SEAT

TORSION

 BAR

SHAFT

 PLUG

THRUST 

BEARING

SEALS

 VALVE

 BODY

SHAFT

PIN

 PISTON

PLUG

RING

 4-1-00