A/C Belt Tensioner - Rattles, Noisey When A/C Engaged
Group 64Heating and
Air Conditioning
Bulletin Number
64 03 95 (4271)
Woodcliff Lake, NJ
August 1995
Product Engineering
SUBJECT:
A/C Belt Tensioner Noise
MODELS:
All models equipped with M50 engines
Situation:
The A/C belt tensioner rattles or drones when the engine is up to operating temperature and the A/C is engaged. The noise is the result of too much axial play between the pitman arm (part number 11 28 1 726 775) and the base plate (part number 11 28 1 726 776).
Repair Procedure:
In case of a customer complaint, it is possible to eliminate the noise by performing the following repair procedure which reduces the amount of axial play.
1. Remove the A/C belt tensioner from the A/C compressor mounting bracket.
2. Remove the bolt that secures the belt tensioner to the base plate.
3. Place the base plate on a vise using brass jaw protectors to prevent damage to the aluminum casting. Use a brass hammer to drive the pin through the base plate approximately 5 mm.
4. Grind off approximately 0.5 mm of the back of the pin.
5. Drive the pin forward until it is flush with the back of the base plate.
6. Using the mounting bolt that goes through the pin, a wide washer and several flat washers with a nut, temporarily mount the pitman arm to the base plate.
There should be no noticeable axial play and the pitman arm should turn freely.
7. If the pitman arm binds, you can remove it and gently tap the outer bearing downward just enough to allow the pitman arm to turn freely.
8. Use the mounting bolt, washers, and nut again to check that there is no noticeable play and that the pitman arm turns freely. Reinstall the A/C belt tensioner assembly.
Warranty Status:
Covered under the terms of the BMW New Car Limited Warranty.
Defect Code: 64 52 04 37 00
Labor Operation: 00 51 127 A/C Belt tensioner repair procedure
Labor Allowance: 7 FRU