Power Steering System: Overhaul GMC Acadia I

Disassembly Procedure

1. Remove the steering gear from the vehicle. Refer to «Steering Gear Replacement»(ref-365269-S39096044982010070600000) .
2. Remove the 2 steering gear boots.
3. Place the steering gear in a vise.
4. Slide the left shock dampener (4) from the left inner tie rod housing (6) to the rack (5).
5. Place a pipe wrench on the rack next to the left inner tie rod housing.
6. Place a wrench on the flats of the left inner tie rod housing.
7. Rotate the left inner tie rod housing counterclockwise, while holding the rack stationary, until the left inner tie rod separates from the rack.
8. Slide the right shock dampener (3) from the right inner tie rod housing (2) to the rack (5).
9. Place a pipe wrench on the left side of the rack.
10. Place a wrench on the flats of the right inner tie rod housing.
11. Rotate the right inner tie rod housing counterclockwise, while holding the rack stationary, until the right inner tie rod (1) separates from the rack.
12. If the steering gear has a female rack (1) and a male inner tie rod (3), remove the old LOCTITE® from the threads (2) on the inner tie rod and from the threads on the rack. If the steering gear has a male rack (5) and a female inner tie rod (4), LOCTITE® will not be present.

Assembly Procedure

1. If the steering gear has a female rack (1) and a male inner tie rod (3), apply LOCTITE® 262, or equivalent, to the threads (2) on the left inner tie rod.
2. Install the left inner tie rod to the rack (3).
3. Place a pipe wrench on the rack next to the left inner tie rod housing (2).
4. Place a torque wrench and the J-34028: wrench on the flats of the left inner tie rod housing. Tighten the inner tie rod to 100 N.m (74 lb ft).
5. If the steering gear has a female rack (5) and a male inner tie rod (1), apply LOCTITE® 262, or equivalent, to the threads on the right inner tie rod.
6. Install the right inner tie rod to the rack.
7. Place a pipe wrench on the rack next to the left inner tie rod housing (4).
8. Place a torque wrench and the J-34028: wrench on the flats of the steering linkage inner tie rod housing (7). Tighten the inner tie rod to 100 N.m (74 lb ft).
9. Place each inner tie rod assembly (2) on a vise.
10. Stake both sides of the 2 female inner tie rod housings to the male rack.
11. Insert a 0.25 mm gage (1) between the rack (2) and the inner tie rod housing in order to inspect the 4 stakes. The feeler gage must not pass between the rack and the inner tie rod housing stake.
12. Slide the left shock dampener (2) over the left inner tie rod housing (3) until the front lip of the left shock dampener bottoms against the left inner tie rod housing.
13. Slide the right shock dampener over the right inner tie rod housing until the front lip of the right shock dampener bottoms against the right inner tie rod housing.
14. Install the 2 steering gear boots.
15. Install the steering gear to the vehicle. Refer to «Steering Gear Replacement»(ref-365269-S39096044982010070600000) .

Scheme 8

The hydraulic power steering pump is a constant displacement vane-type pump that provides hydraulic pressure and flow for the power steering gear. The hydraulic power steering pumps are either belt-driven or direct-drive, cam-driven.

The power steering fluid reservoir holds the power steering fluid and may be integral with the power steering pump or remotely located. The following locations are typical locations for the remote reservoir

1. Mounted to the front of the dash panel
2. Mounted to the inner fender
3. Mounted to a bracket on the engine

The 2 basic types of power steering gears are listed below

1. A recirculating ball system
2. A rack and pinion system

In the recirculating ball system, a worm gear converts steering wheel movement to movement of a sector shaft. A pitman arm attached to the bottom of the sector shaft actually moves one tie rod and an intermediate rod move the other tie rod.

In the rack and pinion system, the rack and the pinion are the 2 components that convert steering wheel rotation to lateral movement. The steering shaft is attached to the pinion in the steering gear. The pinion rotates with the steering wheel. Gear teeth on the pinion mesh with the gear teeth on the rack. The rotating pinion moves the rack from side to side. The lateral action of the rack pushes and pulls the tie rods in order to change the direction of the vehicle's front wheels.

The power steering pressure hose connects the power steering pump union fitting to the power steering gear and allows pressurized power steering fluid to flow from the pump to the gear.

The power steering return hose returns fluid from the power steering gear back to the power steering fluid reservoir. The power steering return line may contain an integral fin-type or line-type power steering fluid cooler.

In a typical power steering system, a pump generates hydraulic pressure, causing fluid to flow, via the pressure hose, to the steering gear valve assembly. The steering gear valve assembly regulates the incoming fluid to the right and left chambers in order to assist in right and left turns.

Turning the steering wheel activates the valve assembly, which applies greater fluid pressure and flow to 1 side of the steering gear piston, and lower pressure and flow to the other side of the piston. The pressure assists the movement of the gear piston. Tie rods transfer this force to the front wheels, which turn the vehicle right or left.