Automotive Air Conditioning Information Forum

Long story short - the AC went out on this. Of course all the BMW forums are full of guys scared or unwilling to work on their own stuff and just say to take it to the dealer and that it needs a new compressor etc. The AC always worked perfect and is only 6 years old so I seriously doubted the compressor was bad. Did some testing at the compressor power wire to confirm it gets voltage which seemed like textbook clutch/coil issue to me. I guess BMW doesn't sell the clutch/coil separately and all I could find was some eBay unit for $48, so I bought that.

Anyway, after an afternoon of frustration and cut up arms and hands from lack of room, I got the clutch/coil/pulley replaced on the vehicle. The air conditioning works now but I did run into a problem.

The shims that came with the new stuff weren't nearly enough. When I tightened the clutch down it practically locked it to the pulley. I knew this wasn't right so I ended up using a combination of original shims plus the new ones to get it to where it "felt" right - but I would like to shim it exactly to proper spec if possible.

Does anybody have a way to find out proper clutch gap on this? I read online that a general "rule of thumb" is .6mm clutch gap but if possible I would like to determine what it should be for this application and make it correct. I can't find anything in BMW literature about it because it appears they just want to charge you $2-3k to replace the entire compressor.

ALSO - how/where can one buy misc. shims? Strangely I can't find much online for this. Is there any reason I can't use random washers that are the right diameter?

The correct gap is one in which the clutch plates don't drag when the clutch is disengaged but not so wide that the clutch only sometimes engages or fails to engage at all. A gap of 0.6 mm (0.024 in.) is in the ballpark, so to speak, although I wouldn't go any wider than that. Typically, I try for about 0.45-0.5 mm (0.018-0.020 inch) or approximately the thickness of a business card.

Perfect, thank you sir! About the shims - I'm not finding any online that aren't like $30+ for a few vehicle specific clutch shims. Is there any reason I can't/shouldn't use a normal washer that fits if it gives the proper gap?

Go to a higher-end bike shop. Ask to see some brake shims. ACE Hardware also.

Tim wrote: ↑Tue Mar 23, 2021 12:47 pm Go to a higher-end bike shop. Ask to see some brake shims. ACE Hardware also.

No higher-end bike shops that I know around, but there are several ACE Hardwares. What exactly would I be looking for there? Brake shims as well?

james89dx wrote: ↑Tue Mar 23, 2021 1:00 pm

Tim wrote: ↑Tue Mar 23, 2021 12:47 pm Go to a higher-end bike shop. Ask to see some brake shims. ACE Hardware also.

.... there are several ACE Hardwares. What exactly would I be looking for there? Brake shims as well?

Just look through all the little drawers, stuff sometimes has "interesting" names.

Did you actually test your old AC clutch to see if the AC clutch electromagnet was actually energizing? Maybe IT'S clutch gap was worn and now a tad too large and could've been fixed by removing a shim (like I did with my 1998 Frontier AC clutch in 2019).

Couldn't you use a shim from your old AC clutch?

eBay.

McMaster-Carr and Century Tool & Equipment also carry the shims you need.