I just installed a 15% pulley on my MCS and when doing the initial test drive the outer nub on the belt got sliced off. The car still runs, but I need to replace the belt. When I installed the belt it took a lot of work. After I pulley the tensioner all the way back it still took a lot of prying to get it on. I got the belt with the pulley as a package from MiniMania. It looked to be quite a bit smaller than stock. Does anyone know if it should be easy to slip on or not?

 

something seems to be wrong. To change the belt, you need to release the tesion with a mini specific tool (although some have made the tool at home with a welder etc).

But make sure that nothing is out of alignment first, or buy two belts in case it happens again!

Matt

 

Moved thread from PM-Cooper(non-S) to PM-Drivetrain.

 

Dr. O is right. You need to loosen the tensioner before you r&r the belt. You probably damaged it when you forced on the new belt.

 

Also make sure it's routed correctly.

 

I thought a 15% pulley didn't require a new belt but instead used the stock one. I thought you changed belts if you went to a 17% or 19%.

I don't have a pulley yet but that's what I've found through a lot of research...
-G

 

15% and 17% pulley can get by with a stock sized belt. The belt should have not been hard to put on. They may have send you a 19% belt by mistake. Do you have a part # for it.

 

Normally a 15% reduction pulley does not REQUIRE a different belt. Some people use a shorter belt but the stock belt is still within the adjustability range of the belt tensioner. There has been a lot of chat on aftermarket belts having issues as well so try to stay with BMW products on this one.

 

A belt changing technique that is sometimes over looked is to route all of the drive pulleys and save the idler pulley for last because it doesn’t have a lip or lands to interfere with the slide over. Talk about a difficult belt install, the MCSa requires the motor jacked up to get the tensioner tool engaged and the wheel well shroud removed to get the belt on.

 

Great tip, thanks!

 

Thanks guys I'll just buy an OEM belt. Lots of good information.

 

As others have asked what was the part number for the belt that the gave you? I know Eric put on a smaller belt for my 17% pulley. I will have to have him show me how to change it when the time comes. Does anyone know of a good way to inspect the belt?

- Garrett

 

I know. I wonder if they have a special tool now for the MCSa, so the techs can change the belt without jacking up the motor. That just seems stupid. It would require the original OEM tensioner tool to be machined down, so it is thin enough to fit down there between the frame and pulleys.