Help - Having trouble getting new AC belt on m30 engine

[Scott E]

I am out of adjustment and the belt wont go on. I cut the old one off. Is there a trick to this?

Thanks

[TheGeak]

prybar maybe? how badly 'wont it go on' is it like, inches short, or just a few millimeteres short? by "out of adjustment' do you mean you're shortened up all the way? I'm not familiar with the M30, but are there any other pully's that adjust on the same belt? are you SURE its the right belt (match it up with the old one?)

[Bill R.]

completely out. then you can move the compressor just a little further in. Then start the belt on the compressor first and pull it onto the crank pulley from the top of the pulley first... usually you can get it like that..





I am out of adjustment and the belt wont go on. I cut the old one off. Is there a trick to this?

Thanks

[Unregistered]

Somebody screwed up bigtime when they mis-printed the supposed correct length of this belt.

My car came with an 855 mm belt, and the idiot mechanic had buggered both the tensioning rack AND the pinion gear putting it on--probably with a crow bar. I had to cut it off. I'll order a new pinion gear, and probably a spare, with the next BMA shipment.

FORGET the 855mm or 860 mm belt, and get a Gates kevlar belt 12.5mm X 875 mm, which fits the V of my pulleys better than the Conti anyhow. The 900 mm belt is too long, so go with 875mm and 12.5 mm width, to make sure it fits down into the V of the pulley, and not riding with its shoulders above the rim.

Remember: If you cannot remove this outer belt, then you're screwed when an inner (i.e. water pump) belt fails, cuz you can't get to it past the non-removable too-short outer AC belt. Not fun at roadside in AZ in August.

A belt length of ~885 mm would be perfect for my car (a '90 535i), but they don't happen to carry that size locally, if anywhere. Bill's technique sounds good, but I have not tried it yet.

[Mr Project]

I got a great tip on this board for this issue....

Pull the bolt and scoot the compressor in as Bill mentioned, then wrap the belt around the compressor and as much as you can around the crank pulley. Make sure you have the belt wrapped so that the crank pulley rotation will pull the belt on, then bump the starter a time or two to rotate the crank pulley. Worked great for me!

[Scott E]

I removed the bolt and used a piece of duct tape to hold the belt onto the crankshaft pully. One bump of the starter and it was on.





completely out. then you can move the compressor just a little further in. Then start the belt on the compressor first and pull it onto the crank pulley from the top of the pulley first... usually you can get it like that..

[Unregistered]

I used the bump-the-starter trick to get my belt on, but I don't think that's really the best way to go: Whatcha gonna do by the side of the road when the water pump or alternator belt quits? Your too-short/bumped-on belt will STILL be in the way, and you'll not be able to bump it off with the starter. So, there you'll be, wishing you'd put on a longer belt in the first place.

So, get a longer (~875mm) belt that you can put on and take off within the range of the rack & pinion setup on your AC compressor.

The 860mm spec. length in the owner's manual is a misprint, so forget it and go to a longer belt.

[Derek A.]

You can also put a rachet/breaker bar on the nose of the crank and turn the motor over by hand. This allows greater control of the belt as its going on the pulley. No doubt about it, major PITA !