The clutch for the air pump on my '92 300e 2.6 just went out and the pulley is too wobbley to drive the car.

I am trying to get it driveable ASAP. I'm thinking of temporarily removing the pump until I can obtain a new clutch or rebuilt pump. In the meantime I will need to install a shorter serpentine belt. Does anyone know what length of belt would be needed to do this?

My '88 260e does not have an air pump but looking at the two engines, I can see that the ider pulleys are different on the two cars. It appears that the idler pulleys are attached to the timing cover so obtaining a replacement idler pulley would involve changing the timing cover (too much work).

If I knew this was so complicated I would have replaced the air pump before it totally died.

Thanks,
John

The idler is mounted on a bracket that bolts to the t-chain cover. No need to remove the t-chain cover to change idlers.

But I believe you can change idlers without changing the bracket. FastLane shows an 88 idler for $35.

Sixto
95 S420
87 300SDL

Hi
Had the same problem with the air pump on my M104 engine before Christmas. In desperation I decided to remove the pump completely and trying to fit the old belt by tightening the belt using the belt tensioner. It turned out to work well and I haven’t had any problem since.

I recall a poster claiming the belt from a *very* early 260E (86?) would fit a later A.I.R. pimp-equipped M103 when the A.I.R. pump had been removed. I filed that in the 'mental bank' in case my A.I.R. pump went out ...

Let us know what you do - the A.I.R. pump replacement would probably exceed the value of our car ....

Brian
89 300TE 195,xxx

One day later and my 300e is back on the road. The air pulley/clutch on the air pump is completely shot so I removed the air pump and installed a shorter serpentine belt for the time being.

The job went flawlessly. I very carefully measured what size belt was needed and bought it at NAPA for $37 (Fastlane sells a much better belt for less but I was desperate). Anyway, the size belt to buy if you are removing the air pump on a M103 is 6PK2365. This number can be used to purchase from NAPA or Fastlane. The belt fit perfectly and car is running quiet. Now I need to see what I can do about fixing the clutch on the air pump.

Digging up an old thread here, because my air pump may be on its way out (will have to check tonight). Car is a 91 300E.

QUESTION: Will the car pass emissions if the pump is removed? I'm due for my test this month and need to know. From what I understand, these pumps are not cheap.

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280