Front suspension noise (knocking)
- Make
- Fiat
- Model
- Croma Factory Service Manual
- Year
- 2005–2010
- Section
- Noise / vibrations › Front suspension noise (knocking)
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 DRIVING
. 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.
| Test results | ||||
| 0 | PRELIMINARY CHECKS | All OK | Problems encountered | Operation |
|---|---|---|---|---|
Having carried out the road test, see the Table See table S015 NOISE WHILST DRIVING there was a knocking noise from the front. Continue depending on the circumstances in which the noise occurs | End of diagnosis | The noise disappears when the brake pedal is operated | Restore the correct tightening of the front brake calipers to the steering knuckle | |
| The noise only occurs during take off and is persistent | Move on to Step 2 | |||
| The noise occurs whilst accelerating or braking with the wheels steered. | Move on to Step 6 | |||
| The noise only occurs during acceleration or braking | Move on to Step 1 | |||
| The noise increases as the engine torque increases | Move on to Step 8 | |||
| The noise is also present in other conditions | Move on to Step 1 | |||
| 1 | OIL LEAKS CHECK | All OK | Problems encountered | Operation |
Raise the vehicle on a two column lift and check that there are no oil leaks from the shock absorber stem The check on the shock absorber should only be carried out after driving on a dry road, slight dampness of the stem is considered normal since this is due to evaporation that takes place during the operation of the shock absorber. If there is persistently oil 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 2 | Leaks from other parts that are lubricated | Search for the cause of the leak following the appropriate diagnostic procedure | |
| Leaks from the shock absorber stem. | Replace the shock absorber | |||
| 2 | CHECK ON CONSTANT VELOCITY JOINT SLIDING | All OK | Problems encountered | Operation |
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 3 | Constant velocity joint seized | Replace the constant velocity joint | |
| 3 | CHECK ON CORRECT TIGHTENING OF DIFFERENTIAL SIDE JOINT FLANGE | All OK | Problems encountered | Operation |
| Check that the bolts fixing the differential side joint flange are correctly tightened. | Move on to Step 4 | Not tightened to torque | Restore the correct tightness | |
| 4 | CHECK ON INTERFERENCE BETWEEN DRIVESHAFTS AND SURROUNDING PARTS | All OK | Problems encountered | Operation |
| Check that there is no interference between the driveshafts and adjacent parts (track control arms, front frame). | Move on to Step 5 | Interference between the driveshafts and adjacent parts. | Restore correct tightening of gearbox side support Op. 1008A42 POWER UNIT RIGID SUPPORT - GEARBOX SIDE - R.R. and engine side support | |
| 5 | CHECK ON CONSTANT VELOCITY JOINT EFFICIENCY | All OK | Problems encountered | Operation |
| Try and move the driveshaft and check that there is not excessive clearance for the constant velocity joints. | Move on to Step 6 | Gearbox side constant velocity joint chamber broken. | Replace the constant velocity joint | |
| Wheel side constant velocity joint chamber broken. | Replace the constant velocity joint | |||
| Wheel side joint worn. | Replace the constant velocity joint | |||
| 6 | WHEEL SIDE BOOTS AND WHEEL BEARINGS CHECK | All OK | Problems encountered | Operation |
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 7 | Boot broken. | Replace the boot | |
| Grease leaks/no grease. | Renew the correct amount of grease of the appropriate type | |||
| Wheel bearing faulty. | Replace the wheel bearing Op. 4450C32 ONE FRONT WHEEL HUB BEARING, LH OR RH - REPLACE on the side where the problem occurs, positioning it with the magnetic race towards the steering knuckle ring. | |||
| 7 | DIFFERENTIAL SIDE BOOT CHECK | All OK | Problems encountered | Operation |
| 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 8 | Boot broken | Replace the boot | |
| Grease leaks/No grease | Renew the correct amount of grease of the appropriate type | |||
| 8 | WHEEL SIDE JOINT TIGHTENING CHECK | All OK | Problems encountered | Operation |
Remove the left wheel Op. 4450B02 LEFT FRONT WHEEL - R.R and/or the right one Op. 4450B04 RIGHT FRONT WHEEL - R.R Check that the constant velocity joint fastening nut is tightened and that the staking is in place. | Move on to Step 9 | Nut loosening | Replace the nut, restore the torque tightening and stake | |
| 9 | INTERFERENCE CHECK | All OK | Problems encountered | Operation |
Check that there are no signs of interference between the suspension elements or between the latter and the bodyshell. 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 10 | Inteference due to incorrect fitting. | Eliminate the interference and restore the correct fastening. If this is not possible, replace the defective components. | |
| Abrasions or non conformity of the spring. | Replace the spring taking care to fit it correctly | |||
| 10 | TRACK CONTROL ARM CHECK | All OK | Problems encountered | Operation |
Check that there are no glycol leaks from the arm rear bush. Check that there is no clearance between track control arm track pin with joint and make sure that the boot is intact. In order to do this it is necessary to remove the guard under the engine, then loosen the bolt connecting the track control arm to the front steering knuckle. Op. 7055B54 UNDER ENGINE PROTECTION/GUARD - R.R. Also check the condition of the track control arm front bush. | Move on to Step 11 | There is a leak of glycol from the arm rear hydraulic bush. | Replace the rear hydraulic bush Op. 4410B52 FRONT SUSPENSION LOWER TRACK CONTROL ARM REAR BUSH LEFT OR RIGHT - REPLACE AT BENCH | |
| There is clearance or the boot or the bush is not intact. | Replace the track control arm | |||
| 11 | TIGHTENING TORQUE CHECK | All OK | Problems encountered | Operation |
Locate the area of the possible noise source: top or bottom. Starting from the area where the knocking was identified, check Op. 4410OA CHECKING CORRECT TIGHTENING OF FRONT SUSPENSION the tightening torques of the fixing bolts: - for the shock absorber to the mounting; - for the steering box rod to the steering knuckle; - for the anti-roll bar to the frame; - for the connecting rod to the bar and to the shock absorber; - for the front connecting rod to the chassis; - for the brake caliper to steering knuckle; Visually inspect that the yield point type bolts have not loosened, the list is given below: - fastening the turret mounting to the bodyshell; - fastening of the semicorner to the steering knuckle; - fastening of the steering box to the chassis; - front fastening between the chassis and the bodyshell; - rear fastening between the chassis and the bodyshell; - fastening of the chassis mounting to the bodyshell; - front fastening of the track control arm to the chassis; - rear fastening of the track control arm to the chassis; - fastening of the rear bush to the track control arm; - fastening of the track control arm to the steering knuckle; | Move on to Step 12 | Standard bolts not tightened to torque. | Restore the correct tightening. | |
| Yield point type bolts loosened. | Replace the yield point type bolts and restore the correct tightening. | |||
| 12 | ANTI-ROLL BAR CHECK | All OK | Problems encountered | Operation |
Check, following the Op. 4410C12 FRONT SUSPENSION ANTI ROLL BAR JOINT (END) (ONE), LH OR RH - R.R after having disconnected the upper track rod end for the shock absorber fork connecting rod, that the anti-roll bar does not come down quickly. Also check that there is not excessive clearance for the pins connected to the bar and to the shock absorber fork. | Move on to Step 13 | The anti-roll bar comes down quickly. | Replace the anti-roll bar Op. 4410C10 FRONT SUSPENSION STABILIZER BAR - R+R - CHECK WHEEL GEOMETRY SEPARATELY | |
| Excessive clearance for the connecting rod connecting pins. | Replace the connecting rod Op. 4410C12 FRONT SUSPENSION ANTI ROLL BAR JOINT (END) (ONE), LH OR RH - R.R | |||
| 13 | CHECK ON CORRECT OPERATION | All OK | Problems encountered | Operation |
| Check that the fault is no longer present | End of diagnosis | The fault persists | The fault is due to another system (engine, clutch, differential). Search for the cause in one of these systems, following the appropriate diagnostic procedures | |
Parts & tools for this job For 2005 Fiat Croma
- TOOLCoil spring compressorSearch: coil spring compressor
- TOOLBall joint separatorSearch: ball joint separator
- PARTFront shock absorbersSearch: Fiat Croma 2005 front shock absorbers
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