Power Steering Pump: Adjustments
POPPET VALVE MANUAL READJUSTMENTNOTE:
The following tools are available from Kent-Moore Tool Division, 23784 Little Mack, Roseville, Ml. 48066. Adjuster Tool J37070, Adjuster Lock Nut Tool J37464.
This resetting procedure will work in most cases with at least 1-3/4 hand wheel turns from side to side of center. If making a large reduction in wheel cut and this procedure does not work, the poppets may need to be internally reset.
The steering gear is equipped with two hydraulic pressure-relieving poppet valves that were automatically set to trip, relieving pressure just before reaching the axle stops. This was achieved after initial installation into the vehicle at the first full right and left turns. The pressure-relieving poppet valves will automatically reset themselves within the poppet adjustment limits if the axle stops are reset for increased steering gear travel based on acceptable equipment revisions from original factory installations.
1. To determine if the poppets require readjustment or if they are carried out correctly, install a Power Steering System Analyzer (PSSA) between the power steering pump and the steering gear. If poppet readjustment is necessary, you can leave the PSSA in the system to verify that the following procedure is completed correctly.
2. Poppets might need to be readjusted if the following conditions exist.
- changing to larger tires
- reduced vehicle wheel cut
- pitman arm mistimed, condition corrected
- steering gear being installed on a different truck
- steer axle stop bolt(s) were bent or broken
- steer axle U-bolt(s) were bent or broken
3. NOTE: An alternate method of manually resetting the poppet valves with the steering gear installed in the vehicle is done by using Ross special service tools, Poppet Adjuster Tool and Adjuster Lock Nut Tool.
Check the maximum turn angle of the front wheels.
4. NOTE:
- The steering gear will have either a fixed stop screw or an adjusting screw. If the adjusting screw is already part of the steering gear, back the nut off the adjusting screw until it is flush with the end of the adjusting screw.
- Only perform the following step with the wheels in the straight-ahead position, the steering gear in its center position and only when the timing marks on the end of the sector shaft and the housing trunnion are aligned.
Turn Adjusting Tool into the non-sealing end of Adjuster Lock Nut Tool until the drive end of the screw is flush with the nut.
5. NOTE: If the unit has a poppet adjusting screw and sealing nut that need to be replaced, remove and discard them.
With the vehicle unloaded, the engine off and tine wheels in the straight-ahead position, remove and discard the fixed stop screw, if so equipped, and the washer from the lower end of the housing.
6. Install the adjusting screw and the sealing nut assembly (without moving the nut on the screw) into the housing until the nut is firmly against the housing. Tighten the sealing nut against the housing.
7. CAUTION: Do not mix fluid types. Mixing transmission fluid, motor Oil, or other hydraulic fluids will cause seals to deteriorate faster.
Fill the power steering reservoir with the specified fluid, Motorcraft MERCON ATFXT-2-QDX or MERCON equivalent.
8. Place a jack under the center of the front axle and jack up the front end of the vehicle so the steering axle tires are off the ground.
9. Start the engine and let it run at idle speed.
10. Note which output shaft timing mark is nearest the housing piston bore.
11. Turn the steering wheel to make right-hand turn (which makes the pitman arm turn in a counterclockwise direction toward the poppet adjusting screw). Turn in this direction until axle stop contact is made.
12. Pull hard on the steering wheel (put 30 pounds of rim pull on a 20-inch diameter steering wheel) after the axle stop is contacted.
13. Turn the steering wheel in the opposite direction (end of timing mark away from the adjusting screw) until the other axle stop is contacted.
14. Pull hard on the steering wheel (put 44 pounds of rim pull on an 18-inch diameter steering wheel).
15. Release the steering wheel and shut off the engine. Do not steer again until Step 18 is completed.
16. Loosen the sealing nut and back out the adjusting screw until it is past the nut. Tighten the sealing nut against the housing.
17. Start the engine and let it idle.
18. CAUTION: Do not hold the steering wheel in this position for more than 10 seconds at a time. Excessive heat buildup can damage components.
Turn the steering wheel in the original direction (end of timing mark toward adjusting screw), until axle stop contact is made.
19. Hold the steering wheel in this position (with 30 pounds rim pull) for 10 seconds, then release. Repeat this hold and release process as many times as necessary while completing Step 21.
20. With the steering wheel held at full lock position, loosen the jam nut and hold it in place with a wrench.
21. NOTE:
- Do not attempt to turn further.
- Pause the turning of the adjusting screw each time the driver releases the steering wheel. Continue turning only while the wheel is held at full turn.
Turn the adjusting screw in (clockwise) using finger pressure only (do not use a ratchet) until the Allen wrench comes to a stop.
22. Back off the adjusting screw 1-1/2 turns and tighten the sealing nut. Tighten the sealing nut to specification.
23. Check the reservoir and fill if required.
24. WARNING: The length of the adjusting screw beyond the nut must be no more than 1-1/16 inch for correct thread engagement.
NOTE: The length of the adjusting screw beyond the sealing nut may be different for each vehicle.
Set the main TAS gear using the procedures described above. Leave the adjusting screws on the rotary cylinders in place as described above after the poppets on the main gear have been reset.
25. Dower the vehicle.