E28 M5 A/C Compressor Clutch Plate Problem

E28 technical advice asked and given! Troubleshooting, modifications and more.
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jjr
Posts: 34
Joined: Apr 21, 2014 2:09 PM
Location: Burlingame, CA

E28 M5 A/C Compressor Clutch Plate Problem

Post by jjr »

The A/C on my E28 M5 was blowing ice cold. However, yesterday, it stopped working suddenly during my commute. Checked the forums, fuse, switches and then visual inspection of the compressor indicated the issue.

The clutch plate has backed itself out. I'm not sure if it oscillated itself out that far, but there isn't enough clearance for it to fall out. Despite it backing this far out, it won't go back in any further by hand (just wobbles on the shaft).

I saw some similar threads, but none were resolved. Thus, I have several questions.

1. Does this look serviceable? If I drop the compressor should I be able to tap this back onto the shaft? Is there a bolt that is meant to retain the clutch plate?
2. The compressor was working fine, so if the whole clutch itself looks toasted, should I try to just R&R that part? There seem to be two different compressors (Seiko and Bosch/Behr), which have specific clutch parts (and I only found the Seiko-compatible clutch on initial search). Is it possible to tell from these photos which one is on my M5? The Seiko is 64 52 1 386 601 and the Bosch/Behr is 64 52 1 386 297.
3. The available clutch part is pretty expensive. Should I just replace with a remanufactured compressor+clutch, even though my compressor and A/C was working fine? If I replace it, does it matter which one 64 52 8 385 713 or 64 52 8 363 550?
4. Unfortunately I don't have the full history of this car. Does the blue valve in the photo below indicate that the A/C was converted to R134? Is there some other way to tell?

Thanks in advance for any advice.

Jason

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travisj
Posts: 1123
Joined: Nov 05, 2009 10:09 PM
Location: Arvada, CO

Re: E28 M5 A/C Compressor Clutch Plate Problem

Post by travisj »

I had the same problem with my compressor. I had a thread started about it awhile ago and you probably came across it. I pulled another compressor from the picknpull and am planning on pulling the clutch off it so I can get a better idea of the assembly and also replace the broken one. The key, I think, is to swap the clutch out without opening the system. I haven't been motivated enough to take the time to do any of this yet though.

Keep us posted on your progress!
Kyle in NO
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Joined: Feb 12, 2006 12:00 PM
Location: Nasty Orleans------> Batten-Rooehjch------>More Souther LA

Re: E28 M5 A/C Compressor Clutch Plate Problem

Post by Kyle in NO »

Looks like the retaining nut has come off, and the shaft is probably galled. Probably new compressor time.
emwexler
Posts: 210
Joined: Apr 21, 2015 9:49 AM
Location: Charlotte NC

Re: E28 M5 A/C Compressor Clutch Plate Problem

Post by emwexler »

Reman bosch n clutch at advance is bout $400, dryer. $35
demetk
Posts: 8427
Joined: Aug 09, 2007 8:58 AM
Location: CT, USA

Re: E28 M5 A/C Compressor Clutch Plate Problem

Post by demetk »

Brand new Sanden 508 type compressor = $130 shipped. Custom brackets = $50.

Edit: And your system looks converted to R134.
jjr
Posts: 34
Joined: Apr 21, 2014 2:09 PM
Location: Burlingame, CA

Re: E28 M5 A/C Compressor Clutch Plate Problem

Post by jjr »

Thanks for the replies everyone. My M5 is still pretty stock (but not totally), so I'll have to weigh the value and cost of trying to keep it that way with going down the cool Sanden hack.

Demet, I saw the latest updates to the thread on the adapter plates and will probably just order a set to give me the option. If I have to wait a couple weeks to get the parts, I might just give salvaging my clutch a shot. I'll post back if it works.
demetk
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Re: E28 M5 A/C Compressor Clutch Plate Problem

Post by demetk »

This begs the question. Is the M5 A/C bracket the same as the M30 bracket?
buzby
Posts: 466
Joined: Feb 10, 2009 8:21 PM
Location: Auburn, CA

Re: E28 M5 A/C Compressor Clutch Plate Problem

Post by buzby »

Yes, they are the same M30-535i E28, E28 M5 and E34 535i M30.

Dave
jjr
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Joined: Apr 21, 2014 2:09 PM
Location: Burlingame, CA

Re: E28 M5 A/C Compressor Clutch Plate Problem

Post by jjr »

I ordered a set of Sanden compressor adapter plates. I figured I had nothing to lose to try to fix the clutch plate. I pulled it down and after fiddling with it a while, I realized why the clutch plate wouldn't easily re-insert. There is a slot on the shaft of the compressor, which has a key in it. It had fallen out of the slot and was now blocking the clutch plate cylinder from going in. After pushing the key back into the slot and lining up the clutch plate, it popped right back in. I was surprised, because I had read about needing a special puller to get it off.

I cleaned as much as I could while I had it apart. One interest I had was getting the make and model of the compressor currently on the car. FWIW, it's a Behr 64521380919, which appears to be replaced by a newer model.

Once I got everything back together, the A/C blowed cold immediately. After inspecting the clutch, I could see it catching and turning, even when it wasn't supposed to be engaged and also when the A/C was completely off. Something was wrong.

I took the kids to swim class and forgot my phone. So, instead of researching the internet for a solution, I was forced to just contemplate my problem. It dawned on my that I had one extra washer left over after reassembling everything (not the first time this has happened). I realized this must be what is used to air gap the clutch.

I took the compressor down again (which went a lot faster the second time - also not the first time I've had to fix things a second time). Now, however, the clutch plate wouldn't just pull off. I feared I now needed the special puller. Coincidentally, I pulled a groin right about then, which slowed me down and also gave me time to think. I cleaned while I considered my options. I didn't really want to jam screw drivers in there to pry it off. The outside of the plate is threaded, but I knew I didn't have a bolt that large in my possession. It was about the size of garden hose. Wait, I have one of those. So I dragged it around from the yard and threaded it right in there. With the proper application of the foot wedge, I was able to yank it right off. I was pleased.

Disclaimer: this is a bush fix as it's clear the threads of a garden hose don't match the metric ones on the clutch plate. Use this method at your own discretion.

I could see now that the pulley spun freely, which I should have checked the first time had I known at the time. The A/C was now working perfectly, with the compressor cycling on and off as needed.

Hopefully these photos and tips will help someone in the future. I've learned so much from this board. Last weekend, I replaced a broken wiper assembly. On Monday, I replaced a frayed accelerator cable, which had frighteningly got stuck at WOT a couple of times in traffic. It always seems to be something with the M5, but so far I haven't let it defeat me.

One last final bush tip: a kid's mini basketball works great to support your head and neck while under the car. Cheers!

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demetk
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Re: E28 M5 A/C Compressor Clutch Plate Problem

Post by demetk »

Holy crap, you used a garden hose and a basketball to fix your compressor?
travisj
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Location: Arvada, CO

Re: E28 M5 A/C Compressor Clutch Plate Problem

Post by travisj »

jjr MacGyver, you are my hero.
Inspiration has hit and I may actually reopen this case again tomorrow.
jjr
Posts: 34
Joined: Apr 21, 2014 2:09 PM
Location: Burlingame, CA

Re: E28 M5 A/C Compressor Clutch Plate Problem

Post by jjr »

demetk wrote:Holy crap, you used a garden hose and a basketball to fix your compressor?
You do what you have to do...
travisj wrote:jjr MacGyver, you are my hero.
Inspiration has hit and I may actually reopen this case again tomorrow.
Travis, go for it. Let me know how I can help.
Kyle in NO
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Joined: Feb 12, 2006 12:00 PM
Location: Nasty Orleans------> Batten-Rooehjch------>More Souther LA

Re: E28 M5 A/C Compressor Clutch Plate Problem

Post by Kyle in NO »

You will still need the center bolt reinstalled to prevent the same thing from happening again. I'd snag one from another BMW in the junkyard and install with thread locker.
travisj
Posts: 1123
Joined: Nov 05, 2009 10:09 PM
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Re: E28 M5 A/C Compressor Clutch Plate Problem

Post by travisj »

Kyle in NO wrote:You will still need the center bolt reinstalled to prevent the same thing from happening again. I'd snag one from another BMW in the junkyard and install with thread locker.
Sorry for the hijack

I didn't get to this task today, but in my case, I do have a fully complete and free spinning unit that I pulled from the yard. I should have all the parts required.
In your opinion (Kahl or others), should I bother ripping the clutch off the yard find unit and try to install on my stock compressor that has been disconnected in the 6 years that I have owned it and in unknown condition? Or should I open the system and install the yard find unit, which is in unknown condition as well?
jjr
Posts: 34
Joined: Apr 21, 2014 2:09 PM
Location: Burlingame, CA

Re: E28 M5 A/C Compressor Clutch Plate Problem

Post by jjr »

Kyle in NO wrote:You will still need the center bolt reinstalled to prevent the same thing from happening again. I'd snag one from another BMW in the junkyard and install with thread locker.
Thanks, Kyle. I did replace the bolt with a locking washer. Will upgrade with locktite if it backs out again. Another issue was not being able to torque it as much as I'd like as it appears that also requires a specialized tool. Hope it stays put. The good news is that there isn't enough clearance for the clutch plate to fall off and get lost.
jjr
Posts: 34
Joined: Apr 21, 2014 2:09 PM
Location: Burlingame, CA

Re: E28 M5 A/C Compressor Clutch Plate Problem

Post by jjr »

travisj wrote:
Kyle in NO wrote:You will still need the center bolt reinstalled to prevent the same thing from happening again. I'd snag one from another BMW in the junkyard and install with thread locker.
Sorry for the hijack

I didn't get to this task today, but in my case, I do have a fully complete and free spinning unit that I pulled from the yard. I should have all the parts required.
In your opinion (Kahl or others), should I bother ripping the clutch off the yard find unit and try to install on my stock compressor that has been disconnected in the 6 years that I have owned it and in unknown condition? Or should I open the system and install the yard find unit, which is in unknown condition as well?
If your current compressor was working well, it might be worth trying to R&R the clutch. You might need some specialized tools to get it off, but to me it's still more of a DIY job than dealing with the R134 when opening the system.
travisj
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Joined: Nov 05, 2009 10:09 PM
Location: Arvada, CO

Re: E28 M5 A/C Compressor Clutch Plate Problem

Post by travisj »

The working condition previous to my ownership is unknown. The clutch was noisy when I got it so I just cut the belt off, and my purchase was basically through a third party so I don't know the history of function. In hindsight, I should have at least checked to see if it worked before cutting the belt. Of all the original owner's records, I don't see any related to the AC. I will probably start by dis-assembly of the junk yard clutch first. The original owner had everything serviced at the dealership and seems like every little thing, so if the AC was out in I think it probably would have come up.
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