Steering - Hissing/Flowing Noise At 10-35 MPH
Date: June 1, 2009Order No.: P-B-46.20/38a
Supersedes: P-B-46.20/38 dated May 4, 2006
Group: 46
Revision History
Revision Date Purpose
a 6/1/09 Applicable Models, Parts and Warranty Information Updated
- 5/4/06 Initial issue
SUBJECT:
Model 221.171/176/177/179
Hissing or Flow Noise at 10 - 35 MPH
If you receive customer reports in the above model vehicles of a gentle hissing or flow noise that may be audible from the area of the steering gear; and the noise only occurs under the following conditions, perform the remedy as indicated below.
Note:
Refer to other publications (e.g. DTB S-B-46.30/40) related to flow or hissing noises from the power steering hydraulic system before making final determination.
Conditions:
1. The engine must be at operating temperature.
2. The noise is most clearly audible in the vehicle speed range between approximately 10 - 35 mph.
Note:
Outside this speed range the noise is barely audible because of the factored actuation of the speed sensitive steering (SPS) valve.
3. In order to reproduce the noise, a vehicle must be driven at a constant curve at the above mentioned vehicle speed range (ramp or a long road turn). The noise becomes louder when the steering is turned further while turning.
Note:
If the noise occurs under conditions other than those provided above, the cause must be sought elsewhere. The noise is similar to that of the mechanical scraping noise from the jacket tube/clock spring contact - please do not confuse noise sources. The noise from the jacket tube/clock spring contact can be reproduced while the vehicle is stationary.
The steering noise addressed in this DTB is caused by the hydraulic vibrations in the power steering system due to actuation of the speed sensitive power steering (SPS) valve, and vibration transmissions as a structure-borne sound.
Remedy:
Note:
The special steering rack and pinion gear may only be installed when the complaint occurs under the above conditions!
1. Remove steering rack and pinion gear and install the special steering rack and pinion gear (A221 460 18 00 28). Refer to WIS document no. AR46.20-P-0600SX.
Note:
Do not damage the support ring or a sealing ring when removing and installing the high pressure power steering at the connection to steering gear control head. If the support ring is damaged, the entire power steering high pressure line must be replaced. It is not possible to replace the support ring separately on model 221.
2. Check the alignment of the vehicle. Refer to WIS doc. No. AR40.20-P-0200SX.
Note:
Always refer to EPC for latest parts information.
Parts Information
Note:
The following allowable labor operations should be used when submitting a warranty claim for this repair. This information has been generated on June 1, 2009. Please refer to Netstar --> Star TekInfo --> Star Time for the most current labor time allowance.
In Case of Warranty, use the table above.