Legacy Postal Wagon AWD F4-2.2L SOHC (1998)
Power Steering Line/Hose: Customer Interest
Steering - Knocking/Rattling Noises
NUMBER: 04-09-01
DATE: 08/15/01
APPLICABILITY:
1995-2000 MY Legacy Vehicles
SUBJECT:
Steering Knocking/Rattle Noise When Turning
If you should encounter a knocking or rattle noise from the vehicle steering system please use the procedures below to diagnose and reduce or eliminate
the noise. The noise is usually heard when turning and going over a bump in the road such as when turning into a driveway. Please keep in mind that
while the noise sounds the same, the cause (and ultimately the repair performed) is different between 1995-99 MY Legacy and 2000 MY Legacy.
EXPLANATION OF MECHANISM AND CAUSE
The power steering assist is created using hydraulic pressure. This pressure is generated by the pump and then distributed through valving on the steering
rack, to the appropriate side of the rack. There is always pressure on both sides of the rack, in order to provide quick steering reaction and a positive feel.
When the steering input is negative, that is, straight driving, the fluid is basically just circulated for lubrication, while maintaining equal pressure. When
the steering wheel is turned, hydraulic pressure is greater on the input side, while some residual pressure is maintained on the free side of the rack.
When turning the steering wheel, even slightly, on rough roads, or especially when entering a driveway over a curb, the tires will input a reactive force
through the rack, caused by the impact. This causes the hydraulic pressure in the input lines to force back against the residual pressure in the free side
lines. When the higher pressure hits the lower pressure, knocking noise is generated.
While some customers may object to this noise, it does not harm the steering system or any of its components. This noise can be reduced or eliminated
by following the procedures below.
REPAIR PROCEDURE
1995-1999 Model Years
If you should encounter the condition on a 95-99 MY it will be necessary to install a Steering Universal Joint With Damper. The Steering Universal Joint
with damper are available in two lengths as shown.
These parts are available through your normal parts channel. Always check the part number suppression for any changes.
After installing the new Steering Universal Joint with damper using the procedures in the appropriate service manual, it will be necessary to drive the
vehicle to confirm the correction.
2000 Model Years
If you should encounter the condition on a 2000 MY, it will be necessary to install a set of Modified Power Steering Lines.
This kit is available through you normal parts channel. Always check the part number suppression for any changes.
After installing the Modified Power Steering Lines using the procedures in the appropriate service manual. It will be necessary to drive the vehicle to
confirm the correction.
WARRANTY INFORMATION/CLAIMS
