939009998 - S027 REAR NOISE (WHISTLING/HUMMING)

Whilst driving, especially on unmade roads, there is a whistling noise coming from the rear suspension. This diagnosis can only be made after See table . Carry out the latter first.
If the problem is only on one side, carry out the checks and any operations on the appropriate side only.
Results of the tests
0PRELIMINARY CHECKSAll OKProblems encounteredOperation
Having carried out the road test, see the Table    S15 RUMOROSITA'' in condizioni di marcia, there was a whistling noise from the back.Continue depending on the circumstances in which the noise occursEnd of diagnosisThe noise increases when corneringReplace the wheel bearing on the side where the noise is loudest Op.    4450C32
This bearing is used by the ABS active sensors to calculate the wheel speed. It should NEVER come into contact with metal shavings or magnetic components (screwdrivers, etc.) because they could alter the gap or damage the codifier and prevent a correct reading from the sensor
The noise increases in vertical oscillation conditionsMove on to Step 2
1BRAKE DISC CHECKAll OKProblems encounteredOperation
Check that the gap between the brake disc and the steel shield is sufficientMove on to Step 2Gap too smallRestore the correct gap.
2SHOCK ABSORBER STEM CHECKAll OKProblems encounteredOperation
Removing the wheel    Op. 4450B12 FRONT WHEELS (TWO) - R+R Check that the noise is not due to irregular friction between the shock absorber stem and the gasket, checking the condition of the stem chrome surface.End of diagnosisThere is irregular frictionLubricate the stem raising the dust cover with a layer of silicon grease. If the noise persists, replace the shock absorber    Op. 4410A12 FRONT SUSPENSION DAMPER (ONE), LH OR RH - FOR MCPHERSON STRUT SYSTEM - INCLUDES DISMANTLING/REASSEMBLY OF ASSEMBLY AT BENCH - R.R