Workshop Manuals Factory service & repair Fiat
01 General information02 Specifications03 Manufacturing data and tolerances04 Tightening torques05 Fluids and lubricants06 Maintenance07 Diagnostic checks08 Engine09 Clutch10 Gearbox and differential11 Axles and driveshafts12 Brakes13 Steering14 Suspension and wheels15 Heating, air conditioning and auxiliary units16 Electrical equipment17 Body fittings18 Body panels and frame19 Wiring diagrams and electrical functions20 Wiring harnesses21 Connectors and pin-outs22 Fault diagnosis23 Special tools
Fiat Croma Factory Service Manual (2005-2010)22 · Fault diagnosis
22 · Diagnostics

Front suspension noise (knocking)

Make
Fiat
Model
Croma Factory Service Manual
Year
2005–2010
Section
Noise / vibrations › Front suspension noise (knocking)
Fault diagnosisFront 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
0PRELIMINARY CHECKSAll OKProblems encounteredOperation

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 diagnosisThe noise disappears when the brake pedal is operated

Restore the correct tightening of the front brake calipers to the steering knuckle

Op. 3310A30 FRONT BRAKE CALIPER (ONE) - R.R

The noise only occurs during take off and is persistentMove 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 brakingMove on to Step 1
The noise increases as the engine torque increasesMove on to Step 8
The noise is also present in other conditionsMove on to Step 1
1OIL 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

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 2Leaks from other parts that are lubricatedSearch for the cause of the leak following the appropriate diagnostic procedure
Leaks from the shock absorber stem.

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

2CHECK 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 3Constant velocity joint seized

Replace the constant velocity joint

Op. 2710A20 WHEEL SIDE CONSTANT VELOCITY JOINT (ONE), L/H OR R/H - R + R WITH DRIVESHAFT REMOVED - INCLUDES BOOT REPLACEMENT

3CHECK ON CORRECT TIGHTENING OF DIFFERENTIAL SIDE JOINT FLANGEAll OKProblems encounteredOperation
Check that the bolts fixing the differential side joint flange are correctly tightened.Move on to Step 4Not tightened to torqueRestore the correct tightness
4CHECK 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 frame).Move on to Step 5Interference 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

Op. 1008A46 POWER UNIT RIGID SUPPORT - TIMING SIDE - R.R.

5CHECK 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 6Gearbox side constant velocity joint chamber broken.

Replace the constant velocity joint

Op. 2710A24 DIFFERENTIAL SIDE CONSTANT VELOCITY JOINT (ONE) L/H OR R/H - R + R WITH DRIVE SHAFT REMOVED - INCLUDES BOOT REPLACEMENT

Wheel side constant velocity joint chamber broken.

Replace the constant velocity joint

Op. 2710A20 WHEEL SIDE CONSTANT VELOCITY JOINT (ONE), L/H OR R/H - R + R WITH DRIVESHAFT REMOVED - INCLUDES BOOT REPLACEMENT

Wheel side joint worn.

Replace the constant velocity joint

Op. 2710A20 WHEEL SIDE CONSTANT VELOCITY JOINT (ONE), L/H OR R/H - R + R WITH DRIVESHAFT REMOVED - INCLUDES BOOT REPLACEMENT

6WHEEL 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 7Boot broken.

Replace the boot

Op. 2710A20 WHEEL SIDE CONSTANT VELOCITY JOINT (ONE), L/H OR R/H - R + R WITH DRIVESHAFT REMOVED - INCLUDES BOOT REPLACEMENT

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.

7DIFFERENTIAL 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 8Boot broken

Replace the boot

Op. 2710A24 DIFFERENTIAL SIDE CONSTANT VELOCITY JOINT (ONE) L/H OR R/H - R + R WITH DRIVE SHAFT REMOVED - INCLUDES BOOT REPLACEMENT

Grease leaks/No greaseRenew the correct amount of grease of the appropriate type
8WHEEL SIDE JOINT TIGHTENING CHECKAll OKProblems encounteredOperation

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 9Nut loosening

Replace the nut, restore the torque tightening and stake

Op. 2710A20 WHEEL SIDE CONSTANT VELOCITY JOINT (ONE), L/H OR R/H - R + R WITH DRIVESHAFT REMOVED - INCLUDES BOOT REPLACEMENT

9INTERFERENCE CHECKAll OKProblems encounteredOperation

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 10Inteference 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

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 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 11There 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

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

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 12Standard 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.
12ANTI-ROLL BAR CHECKAll OKProblems encounteredOperation

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 13The 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

13CHECK ON CORRECT OPERATIONAll OKProblems encounteredOperation
Check that the fault is no longer presentEnd 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

Parts & tools for this job For 2005 Fiat Croma

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