312000772 - S018 FRONT SUSPENSION NOISE (KNOCKING)

Whilst driving, especially on unmade roads, there is knocking coming from the front suspension. This diagnosis can only be made after    See table S015 NOISE WHILST DRIVINGCarry out the latter first.
If the problem is only on one side, carry out the checks and any operations on the appropriate side only.
Test results
0PRELIMINARY CHECKSAll OKProblems encounteredOperation
Having carried out the road test, during the    See table S015 NOISE WHILST DRIVING, there was a knocking noise from the front.Continue according to the circumstances in which the noise occursEnd of diagnosis1. The noise disappears when the brake pedal is operated2. The noise occurs whilst accelerating or braking with the wheels steered.3. The noise only occurs during acceleration or braking4. The noise is also present in other conditions.1. Restore the correct tightening of the front brake calipers to the steering knuckle.2. Replace the wheel bearing on the side where the fault occurredOp. 4450C32 , fitting it with the magnetic track facing the steering knuckle seal
This bearing is used by the ABS active sensors to calculate the wheel speed. It should NEVER come into contact with metal shavings because they could alter the gap and prevent a correct reading from the sensor
3. Move on to Step 14. Move on to Step 1
1CHECK ON CONSTANT VELOCITY JOINT SLIDINGAll OKProblems encounteredOperation
Raise the vehicle on a two column lift and rotate the front wheels by hand.Make sure that there are no impediments to the movement or noise during rotation.Move on to Step 21. Constant velocity joint seized1. Replace the constant velocity jointOp. 2710A54 WHEEL SIDE CONSTANT VELOCITY JOINT (ONE), LEFT OR RIGHT - R + R WITH DRIVESHAFT REMOVED - INCLUDES BOOT REPLACEMENT
2CHECK ON CORRECT TIGHTENING OF DIFFERENTIAL SIDE JOINT FLANGEAll OKProblems encounteredOperation
Check that the bolts fixing the differential side joint flange are correctly tightened.
"Only for vehicles with flanged driveshafts".
Move on to Step 32. Not tightened to torque2. Restore the correct tightening.
3CHECK ON INTERFERENCE BETWEEN DRIVESHAFTS AND SURROUNDING PARTSAll OKProblems encounteredOperation
Check that there is no interference between the driveshafts and adjacent parts (track control arms, front crossmember).Move on to Step 43. Interference between the driveshafts and adjacent parts.3. Restore correct tightening of gearbox side support and engine side support.
4CHECK ON CONSTANT VELOCITY JOINT EFFICIENCYAll OKProblems encounteredOperation
Try and move the driveshaft and check that there is not excessive clearance for the constant velocity joints.Move on to Step 51. Gearbox side constant velocity joint chamber broken2. Wheel side constant velocity joint chamber broken3. Wheel side joint worn.1. Replace the constant velocity jointOp. 2710A24 DIFFERENTIAL SIDE CONSTANT VELOCITY JOINT (ONE) L/H OR R/H - R + R WITH DRIVE SHAFT REMOVED - INCLUDES BOOT REPLACEMENT2. Replace the constant velocity jointOp. 2710A54 3. Replace the constant velocity jointOp. 2710A54
5WHEEL SIDE BOOTS AND WHEEL BEARINGS CHECKAll OKProblems encounteredOperation
Check the condition of the wheel side boot.If it is not intact, check that there are no leaks or no grease in the actual boot.If everything is okay and the noise was more pronounced whilst steering, check the wheel bearings.Move on to Step 61. Boot broken.2. Grease leaks/no grease.3. Wheel bearing faulty.1. Replace the bootOp. 2710A54 2. Renew the correct amount of grease of the appropriate typeOp. 2710A54 3. Replace the wheel bearing on the side where the fault occurredOp. 4450C32 , fitting it with the magnetic track facing the steering knuckle seal.
This bearing is used by the ABS active sensors to calculate the wheel speed. It should NEVER come into contact with metal shavings because they could alter the gap and prevent a correct reading from the sensor.
6DIFFERENTIAL SIDE BOOT CHECKAll OKProblems encounteredOperation
Check the condition of the differential side boot.If it is not intact, check that there are no leaks or no grease in the actual boot.Move on to Step 71. Boot broken2. Grease leaks/No grease1. Replace the bootOp. 2710A24 2. Renew the correct amount of grease of the appropriate typeOp. 2710A24
7WHEEL SIDE JOINT TIGHTENING CHECKAll OKProblems encounteredOperation
Remove the wheel Check that the constant velocity joint fastening nut is tightened and that the staking is in place.Move on to Step 84. Nut loosening4. Replace the nut, restore the torque tightening and stake.
8OIL LEAKS CHECKAll OKProblems encounteredOperation
Raise the vehicle on a two column lift and check that there are no oil leaks from the shock absorber stem.
Slight dampness on the stem is considered normal because there is evaporation during the operation of the shock absorber.
If there is a persistent oil leak on the shock absorber stem, make sure that it is not coming from other parts of the vehicle that are lubricated
Move on to Step 91. Leaks from other parts that are lubricated1. Leaks from the shock absorber stem1. Search for the cause of the leak following the appropriate diagnostic procedure1. 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
9INTERFERENCE CHECKAll OKProblems encounteredOperation
Check that there are no signs of interference between the suspension elements and the bodyshell and between the latter and the liner.In particular, check that there are no signs of wear on the suspension springs and that they do not show signs of abrasion.
If the spring shows signs of abrasion, its mechanical properties could be weakened as a result of oxidation
Move on to Step 102. Inteference due to incorrect fittingAbrasions or non conformity of the spring2. Eliminate the interference and restore the correct fastening. If this is not possible, replace the defective componentsReplace the spring    Op. 4410A12 FRONT SUSPENSION DAMPER (ONE), LH OR RH - FOR MCPHERSON STRUT SYSTEM - INCLUDES DISMANTLING/REASSEMBLY OF ASSEMBLY AT BENCH - R.R taking care to fit it correctly
10TRACK CONTROL ARM CHECKAll OKProblems encounteredOperation
Check that there is no clearance between the track control arm ball joints and that the boot is intact; to do this loosen the bolt connecting the track control arm to the front steering knuckle.Also check the condition of the suspension bushesMove on to Step 11There is clearance or the boot or the bushes are not intactReplace the track control arm    Op. 4410B40 LOWER TRACK CONTROL ARM (WITH BALLJOINT) FOR LEFT OR RIGHT FRONT SUSPENSION (ONE) - R+R - CHECK WHEEL GEOMETRY SEPARATELY
11TIGHTENING TORQUE CHECKAll OKProblems encounteredOperation
Locate the area of the possible noise source: top or bottom.Starting from the area where the knocking was identified, check by carrying out the    See Test 4410OA CORRECT TIGHTENINGS FOR FRONT SUSPENSION CHECKthe tightening torques of the fixing bolts for:

  • Shock absorber stem to turret mounting end of travel plate
  • To the shock absorber bracket strut
  • The steering box to the crossmember
  • The steering rod to the steering knuckle
  • The anti-roll bar to the crossmember
  • The connecting rod to the shock absorber
  • The connecting rod to the anti-roll bar
  • The front bush for the arm to the crossmember
  • The rear bush for the arm to the crossmember
  • The track control arm ball joint to the steering knuckle
  • The front fastening securing the crossmember to the body side member
  • The middle rear fastening securing the crossmember to the bracket on the floor
  • The rear fastening securing the crossmember to the body side member
  • The fastening securing the third load line to the crossmember
  • The side fastening securing the third load line to the crossmember
  • The side rod fastening to the crossmember and to the body
  • The engine mounting connecting rod to the crossmember
  • The fastening securing the brake caliper to the steering knuckle
Move on to Step 12Torque tightenings not correctRestore the correct tightness
12SHOCK ABSORBER FASTENING CHECKSAll OKProblems encounteredOperation
Check that there is no clearance between the shock absorber attachment bearing and the rubber mounting and that the bearing is in place.Move on to Step 131. There is clearance for the bearing2. The bearing is not in place1. Replace the bearing    Op. 4410A12 FRONT SUSPENSION DAMPER (ONE), LH OR RH - FOR MCPHERSON STRUT SYSTEM - INCLUDES DISMANTLING/REASSEMBLY OF ASSEMBLY AT BENCH - R.R 2. If the bearing is not damaged, fit it correctly. If this is not the case, replace the mounting.
13CORRECT OPERATION CHECKAll OKProblems encounteredOperation
Check that the fault is no longer present.End of diagnosisThe fault persistsThe fault is due to another system (engine, clutch, differential). Search for the cause in one of these systems, following the appropriate diagnostic procedures