Diagnostic Information
If the drive belt has repeatedly slipped off the pulley (ov), then it may be caused by misalignment of the pulley.
Additional load that has been quickly applied or released by the accessory drive can also cause the drive belt to slip. Verify that the accessory drive components are working properly.
If the drive belt is not the correct length, the tensioner may not be able to provide the required belt tension.
Description of the test
The numbers below refer to the operations in the diagnostic table:
2. This inspection is performed to check the condition of the drive belt. If the drive belt slipped, it could be damaged. Inspect the belt for cuts, breaks, damaged belt layers, or missing rib sections.
4. Misalignment of the accessory drive pulleys may be caused by incorrect installation of the accessory drive pulley itself or the accessory drive component, or the pulley may have been bent during a previous repair. Check the alignment of the pulleys on the plane by applying a ruler to the grooves of two or three pulleys. If an offset pulley is found, verify that the mounting and dismounting procedures for that accessory drive pulley match.
5. Pulley Inspection (ov) accessory drive must include an inspection for kinks, dents, or other damage that would prevent the drive belt from properly fitting into the pulley grooves or from resting on a smooth surface when the back of the drive belt is used to drive the pulley.
6. Bent or cracked accessory drive component brackets can also cause the drive belt to slip.
7. Inspection of fasteners will help eliminate the possibility of incorrectly installing a bolt, nut, gasket, or washer. Missing, loose, or inappropriate fasteners can cause the pulley to align with the bracket (ami) accessory drives when operating under load. Over-tightening the fasteners can cause the bracket to skew (ov) accessory component.
| Step | Operation | Values | Yes | No |
| 1 |
Have you read the diagnostic information Symptom - Engine Mechanical and performed the necessary inspections?
|
-
|
Go to operation 2
|
Go to item Symptoms - Engine Mechanical
|
| 2 |
Inspect the drive belt for damage.
Has the drive belt been damaged?
|
-
|
Go to operation 3
|
Go to operation 4
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| 3 |
Install a new drive belt. See Section 1C1, Engine Mechanical - FAM II 2.4D.
Does the drive belt keep slipping?
|
-
|
Go to operation 4
|
System OK
|
| 4 |
Check accessory drive pulley alignment.
Fault found and corrected?
|
-
|
Go to operation 12
|
Go to operation 5
|
| 5 |
Inspect the accessory drive pulley for kinks or dents.
Fault found and corrected?
|
-
|
Go to operation 12
|
Go to operation 6
|
| 6 |
Inspect Bracket (s) drive accessories for cracks and bends.
Fault found and corrected?
|
-
|
Go to operation 12
|
Jump to Operation 7
|
| 7 |
Inspect for correct installation, looseness and/or missing fasteners.
Were incorrectly installed, loose and/or missing fasteners found?
|
-
|
Jump to operation 8
|
Go to operation 9
|
| 8 |
Does the drive belt keep slipping?
|
-
|
Go to operation 9
|
System OK
|
| 9 |
Check the correct operation of the drive belt tensioner. Refer to Drive Belt Tensioner Diagnosis.
Is the drive belt tensioner working properly?
|
-
|
Go to operation 11
|
Jump to operation 10
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| 10 |
Replace drive belt tensioner. Refer to Drive Belt Tensioner Replacement.
Does the drive belt keep slipping?
|
-
|
Go to operation 11
|
System OK
|
| 11 |
Check the condition of the drive belt idler pulley bearings and/or tensioner pulley.
Fault found and corrected?
|
-
|
Go to operation 12
|
-
|
| 12 |
Start the engine to check the results of the repair.
Does the drive belt still slip?
|
-
|
-
|
System OK
|