AC Compressor

[t t]

Hey All,

I am having a hard time finding a replacement AC Compressor that will last more than 6mos for my 91’ M5. Last one was 4Seasons, go figure. This time all Freon (still running R12) seems to have leaked out the front seal btwn pulley and comp. Anyone know of a reputable place that will rebuild/reseal the compressor? I still have the factory compressor so might have that one rebuilt/resealed as well if possible.

Travis

[Richard Baxter]

There is someone in the USA that restores them - will try to find the details….

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[Ted Staib]

I ordered a kit like this a month ago to have mine rebuilt. 

BMW Sealing Part Number: 64521381193 | eBay

I paid more than that. The other seals are probably NLA. I found a guy in the US on the forums who supposedly rebuilt them. I emailed him and then called him. Turned out to be the biggest a-hole I've ever dealt with. He told me to quit wasting his time and hung up on me, after one email and one phone call to inquire about his services. Send me his name if you find it, I can't remember off-hand. 

Other than that, I think we're looking at A/C Solutions | The original plug-and-play A/C solution.

But they don't have the hoses for our M5's. A guy near me might be interested in creating the hoses, working with a shop near us. If this seal kit does not work for me, I'll look into that option, because I need A/C in my black on black M5!

Ted Staib

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[RODGER SOUCY]

Travis:

Yellow Rose Distributing, Fort Worth, Texas might be worth a call. They do automotive compressors foreign and domestic.  They have rebuilt several OE Bosch units from E-28/34’s for me over the years.  

Cheers,

Rodger

On Oct 29, 2025, at 2:49 AM, 'Richard Baxter' via BMW E34 ///M5 <bmw-e...@googlegroups.com> wrote:

There is someone in the USA that restores them - will try to find the details….

To view this discussion visit https://groups.google.com/d/msgid/bmw-e34-m5/A65D7906-39F2-4BC7-9EFD-B7C6FC65FB6B%40btinternet.com.

[Jeff Gomon]

So if these compressors can be rebuilt, and there is a vendor to accomplish this, are they being rebuilt using materials that are compatible with R134a or compatible with R12?  I ask because my compressor is functional and works with R12 / Freeze12 but would get it refreshed if it was compatible with a conversion to 134.  I would just flush the lines, install a new receiver drier, expansion valve, service port adapters, fresh 134 compatible oil and send it. 

D. Jeff Gomon

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On Oct 29, 2025, at 8:20 AM, RODGER SOUCY <rmini...@gmail.com> wrote:



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[Gary Derian]

I recommend a propane butadiene mix.  Cheap, effective, and low greenhouse/ozone effect.  This is basically what the new 1234yf refrigerant is.  The refrigeration industry would never allow individuals to concoct their own stuff.  Envirosafe 12a is a pre-made mixture of this.  Yes, it is flammable, but there is a lb or so in the AC system compared to 100 lb of gasoline in the tank.  A shop can't use it, but an individual can.  Mark the fittings so the next guy doesn't pollute his stash.

Gary Derian

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To view this discussion visit https://groups.google.com/d/msgid/bmw-e34-m5/DC46D166-56C8-49D9-8A80-7017FDF9AE82%40gmail.com.

[Jeff Gomon]

Good stuff ,Gary!!  Great information.  

Hope you are doing well!  FYI, My cluster is still working perfectly.  I

 am still running Johnson’s “Freeze 12” in my original a/c system on my M5.  Says it is non-flammable and has no CFC’s.  Not sure that’s true, but non the less, every 2 years I need to top it up, but can’t find a leak anywhere.  I was able to source an unopened case of 10 cans this summer for $90.00 !!!!  Could not pass it up.  I don’t think they sell it anymore so they must have tightened up the restrictions at some point.  

D. Jeff Gomon

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On Oct 29, 2025, at 2:07 PM, Gary Derian <gade...@gmail.com> wrote:



[Gary Derian]

Hey Jeff!  Freeze 12 definitely has CFCs in it.  It is mostly R134a plus some other stuff to dissolve and circulate the mineral oil used in R12 systems.  Meh, it works.  R134a is a tiny molecule and it leaks out of places where other refrigerants don't including right through the old hoses.  I have replaced all the o-rings in my system and the leakage stopped.  I also have some newer E34s with the barrier hoses.  Since I use propane/butadiene refrigerant, regular neoprene o-rings work.  R134a requires some other rubber.  A pack of o-rings should be easy to get.  The hardest joint is the one up front for the condenser.  The most pain to get to is the H valve under the cover by the passenger's feet, also the short little pipe in the cowl.

BTW, I recently picked up two Euro spec E34s with slick tops.  One 524tds and one 520i.  Both are getting LS swaps.  S38s are wonderful engines but this is 2025 and they belong in a museum with that fancy header uncovered.

Gary Derian

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[Ben Trigg]

My complaint with freeze 12 is that I can't find anyone to touch it now. The shops with the R12 fittings don't want to contaminate their equipment.

To view this discussion visit https://groups.google.com/d/msgid/bmw-e34-m5/CAOTtLQbY0kdWnO_ie%3DHuGxTNK9kOrkczReoJxXPLDQo2R6emJw%40mail.gmail.com.

[Gary Derian]

This is the problem with any substitute.  You are committed to DIY.

Gary Derian

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[Jeff Gomon]

That’s why I bought a used Robin Air  manifold gauge set, a side puncture can adapter and service it myself using the stock R12 ports.  It’s not difficult at all.  You can even borrow a vacuum pump from many auto parts stores to evacuate the system and check for leaks. 

D. Jeff Gomon

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On Oct 29, 2025, at 5:54 PM, Ben Trigg <org...@gmail.com> wrote:



My complaint with freeze 12 is that I can't find anyone to touch it now. The shops with the R12 fittings don't want to contaminate their equipment.

On Wed, Oct 29, 2025, 1:27 PM Gary Derian <gade...@gmail.com> wrote:

Hey Jeff!  Freeze 12 definitely has CFCs in it.  It is mostly R134a plus some other stuff to dissolve and circulate the mineral oil used in R12 systems.  Meh, it works.  R134a is a tiny molecule and it leaks out of places where other refrigerants don't including right through the old hoses.  I have replaced all the o-rings in my system and the leakage stopped.  I also have some newer E34s with the barrier hoses.  Since I use propane/butadiene refrigerant, regular neoprene o-rings work.  R134a requires some other rubber.  A pack of o-rings should be easy to get.  The hardest joint is the one up front for the condenser.  The most pain to get to is the H valve under the cover by the passenger's feet, also the short little pipe in the cowl.

BTW, I recently picked up two Euro spec E34s with slick tops.  One 524tds and one 520i.  Both are getting LS swaps.  S38s are wonderful engines but this is 2025 and they belong in a museum with that fancy header uncovered.

Gary Derian

Virus-free.www.avast.com

On Wed, Oct 29, 2025 at 3:33 PM Jeff Gomon <jeff...@gmail.com> wrote:

Good stuff ,Gary!!  Great information.  

Hope you are doing well!  FYI, My cluster is still working perfectly.  I

 am still running Johnson’s “Freeze 12” in my original a/c system on my M5.  Says it is non-flammable and has no CFC’s.  Not sure that’s true, but non the less, every 2 years I need to top it up, but can’t find a leak anywhere.  I was able to source an unopened case of 10 cans this summer for $90.00 !!!!  Could not pass it up.  I don’t think they sell it anymore so they must have tightened up the restrictions at some point.  

[Richard Baxter]

Gents

As mentioned earlier - here is the USA guy. I came across him from one of the forums:  https://www.jaysbmwparts.com based in California from my recollections.

I’m from the Uk, and did email him to see if he'd  repair the unit from my E30 M3 - but he only deals with USA clients.

In the end I restored it myself after a long and arduous search -  that the unit was ’Sanden’ and not directly Bosch/Behr as the identification label showed. I managed to purchase the seal kit from the USA and the bearings and clutch items from BMW along with new hoses and the condenser and evaporator.

I’m at the point of being ready to refit the system (I removed it over 20 yrs ago to lose weight in what was essentially my track day car) but will also remove and clean out the ‘interior side’ (which remained in situ)).

I’ve also purchased the manifold set, an evacuation tank and a vacuum pump (those more for my M5) however I’m at the point of being undecided whether to go R12 which by all accounts is a better refrigerant and would then use mineral oil in the compressor, or to go 134a and use the mag oil.

The one thing that I discovered along the way is that R12 is not illegal to buy/sell/use (as many in the Uk seem to say it is) it is only illegal to manufacture. But as mentioned by others it is definitely a DIY application only and hence why I’ve purchased the necessary equipment. However no one seems to have R12 in the Uk but still holding out in the hope some old stock might show up.

I did find a very helpful chap in the states who kindly posted over two old cans of R12 for my E28 M5 for a top up - so far however the original gas is still in the car and does cool the air so I’ve yet to use it. With my 1992 E34 M5 it started with R12 but had it refilled in 2001 with some variant gas i.e. retained all the R12 components (condenser etc) but it lasted 2 weeks and since then have cracked open the window when it gets too hot - but I do plan to completely rebuild the system in the near future.

I’ll make a decision with the M3 across the winter ready for reinstallation in February/March and then plunge in at the deep end as I have no prior experience of this work - however I’ll do this  with the aid of the air con book by Rob Siegel “Just Needs a Recharge” which I was recommended to read and found a copy on Amazon…

Good luck everyone with their air con systems…

Richard

To view this discussion visit https://groups.google.com/d/msgid/bmw-e34-m5/790A1FEA-6451-4281-8F50-2016AAC29032%40gmail.com.

[Ted Staib]

Jay is the big a-hole that I mentioned earlier. I had all the seals and I planned to send him everything he needed, but he yelled at me and hung up before I could get a word in. Save your time and frustration. Don't contact him.

Ted Staib

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[Gary Derian]

DIY is great.  R12 was perfect back when it was less than $1 a can.  Today, there is no reason to use it.  HC refrigerants work as well and still use mineral oil.  If you want perfection, the pressure setting of the H valve can be adjusted.

Gary Derian

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[Blue Ridge Mercedes]

Propane works great and doesn't leak out unevenly like a blend would.  If we have an R12 system that isn't Perfectly tight, propane is cheap and easy.  Double benefit of it runs even Lower pressures vs 12.  Never a bad thing on aging systems.

I do have a stash of over 150lbs of r12 on hand though....and for freshly rebuilt systems that hold their vac and N test charge ill fill em up;)

Jono

www.blueridgemb.com
404.805.1357
jo...@blueridgemb.com
#blueridgemb

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[RODGER SOUCY]

Jeff:

Answering your question.  When I had my OE units rebuilt by Yellow Rose in Fort Worth, they used newer materials seals etc compatible with the later oils used these days both 134 variants and 12.  As far as converting from 12 to 134, I did the ‘complete’ conversion on one of my E-28 M5’s with a new ‘134’ drier complete with 134 pressure sensors (threads were different from the 12 sensors).  IMHO it wasn’t worth the hassle.  I kept my other E-28 R12 when rebuilt.  Both compressors rebuilt by Yellow Rose have worked fine with no leaks.  Havent had to put any R12 in that M5 for 7 years!  Fingers crossed for that next Texas summer!  LOL   

On Oct 29, 2025, at 1:01 PM, Jeff Gomon <jeff...@gmail.com> wrote:

So if these compressors can be rebuilt, and there is a vendor to accomplish this, are they being rebuilt using materials that are compatible with R134a or compatible with R12?  I ask because my compressor is functional and works with R12 / Freeze12 but would get it refreshed if it was compatible with a conversion to 134.  I would just flush the lines, install a new receiver drier, expansion valve, service port adapters, fresh 134 compatible oil and send it. 

[Jeff Gomon]

Thanks Rodger!  

I will most likely continue with the R12 blends but do as Gary suggested and install fresh o-rings throughout the system.  That seems a logical place for it to leak over time.  I could try to tighten them a little, but if I’m right there to tighten anyway, might as well swap the o-rings at that point.

Oh the joys of owning “older” cars…. Says the guy with a 1970 2002 and a 1972 2002tii….. it’s always something…lol

D. Jeff Gomon

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On Oct 30, 2025, at 10:11 AM, RODGER SOUCY <rmini...@gmail.com> wrote:



[mrm...@sympatico.ca]

One good thing is that our older cars are easy to work on vs the overload of electronics/hard to reach parts on new cars…. :-)

 

Mark Rousseau

To view this discussion visit https://groups.google.com/d/msgid/bmw-e34-m5/95BBA595-8D13-4EED-96B8-22CC87112C60%40gmail.com.

[Jeff Gomon]

I agree 100% Mark.  That said, the E34 is still like a spaceship compared to working on my 2002’s…. One has only 6 fuses for the entire car, the other has 12 fuses.  The wire harnesses are not complicated at all and repairs are easy.

But my M5 is easier to work on than my M2C or my wife’s F15 X5 diesel!!!!  Lots of wires and multiple fireboxes in various locations on these newer cars.  And you need a computer and IPNA to diagnose or modify anything. 

D. Jeff Gomon

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On Oct 30, 2025, at 10:29 AM, mrm...@sympatico.ca wrote:



Contact us yellowrosedistributors.com <image001.png>

 

On Oct 29, 2025, at 2:49 AM, 'Richard Baxter' via BMW E34 ///M5 <bmw-e...@googlegroups.com> wrote:

There is someone in the USA that restores them - will try to find the details….

On 28 Oct 2025, at 16:55, 't t' via BMW E34 ///M5 <bmw-e...@googlegroups.com> wrote:

 

Hey All,

 

I am having a hard time finding a replacement AC Compressor that will last more than 6mos for my 91’ M5. Last one was 4Seasons, go figure. This time all Freon (still running R12) seems to have leaked out the front seal btwn pulley and comp. Anyone know of a reputable place that will rebuild/reseal the compressor?  I still have the factory compressor so might have that one rebuilt/resealed as well if possible.

 

Travis

 

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[t t]

You guys are the absolute best, thanks everyone for your valuable input! I will reply to this thread when I confirm path I am taking. 

As a side note, I also reached out to Greg @ Angry Ass.  They are working on an AC bracket that will allow e34m5 to run a modern (easy to find) AC compressor. ETA is Summer 26’. 

Travis

On Oct 30, 2025, at 8:46 AM, Jeff Gomon <jeff...@gmail.com> wrote:

I agree 100% Mark.  That said, the E34 is still like a spaceship compared to working on my 2002’s…. One has only 6 fuses for the entire car, the other has 12 fuses.  The wire harnesses are not complicated at all and repairs are easy.

[Neil Deshpande]

Travis:

I helped a friend mount a modern compressor to his E34 M5 by designing a bracket I tested via 3D print and then had machined via Xometry for $52 delivered. It was polished and looked amazing! This is the way!

I have a Sanden rotary vane unit with similar bracket on my 1994 Nissan pickup and it “meat lockers” the cab. My M5 will probably receive the same treatment in Spring.

Neil

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On Oct 30, 2025, at 1:31 PM, 't t' via BMW E34 ///M5 <bmw-e...@googlegroups.com> wrote:



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[t t]

Neil, you have my attention. Not sure I have the skills to recreate this process. You think Xometry would still have the CAD file or whatever was used to create the machined bracket? I’m curious to see pics of the bracket if you have any. Thanks again everyone. 

Travis

On Oct 30, 2025, at 12:12 PM, Neil Deshpande <neilde...@yahoo.com> wrote:

Travis:

[Neil Deshpande]

Hello Travis:

I've got the CAD file and am happy to share it and drawings, but it was specific to my friend's application of going between his compressor and whatever bracket there was on the S38 block. It ended up looking like the drawing below. I believe the wider end went over whatever is on the block side and the narrower end went between the compressor "ears".

I printed it, he fitted it and confirmed it worked, and then I sent a set of drawings to Xometry.

When I did the Sanden on my 1994 Nissan, all the adaptors were available along with the compressor for $250. <LOL>. I'm very impressed with the cooling performance so would go for the same option on my M5.

Best regards,

Neil Deshpande

To view this discussion visit https://groups.google.com/d/msgid/bmw-e34-m5/BDCD468D-2197-4E11-971C-1ECFFB808A98%40yahoo.com.

[Neil Deshpande]

Hello Travis:

It looks like there are some folks making these brackets. $150-170 is a reasonable price, IMO.
https://lcwylieco.bigcartel.com/product/bmw-sanden-conversion-bracket
https://www.acsolutions.co/collections/bmw-e34/products/a-c-solutions-bmw-m20-m30-s38-sanden-compressor-bracket-e30-e28-e24-etc

Even though I could re-engineer this solution relatively easily and I wish they'd improved the adjustment methodology, I'd just pay to have it done quicky.

Best regards,

Neil Deshpande

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[helpmeob1]

I removed my secondary air pump from my M5 and installed the bracket from a E34 535, the bracket Neil made was to keep my original compressor adjustable.  I have pictures but they are not on my phone.  The dimensions for the end b/t the compressor ears needs to be 0.5mm bigger.

To view this discussion visit https://groups.google.com/d/msgid/bmw-e34-m5/865401141.3162445.1761971880977%40mail.yahoo.com.

[Gary Derian]

I also removed my air pump.  I changed the AC hose ends to fit the 535 setup and used the factory belt tensioner.  Those hoses were standard AN dash size.  I fitted fire sleeve as hose insulation to replace the deteriorated factory insulation.  This must have been 20 years ago.

Gary Derian

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[trav...@yahoo.com]

Hi Rodger, just wanted to circle back. Thanks for the recommendation. I reached out to Eric @ Yellow Rose and he said they aren’t rebuilding the e34m5 compressor any longer as parts are hard to find. —- However, Michael @ acsolutiins.co said I could use their Sanden bracket & compressor as long as I remove smog pump (which I intend to remove anyway). 

Travis

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[RODGER SOUCY]

Travis!

Thanks for the update.  It’s been about 7 years since I had the last Bosch done. Good to know.  It will be a race to see which goes next, timing chain guide or compressor in my 285k mile E28 M5!  Everything still works!

Merry Christmas and good luck!

Again, thanks for the update. 

On Dec 24, 2025, at 12:55 AM, trav...@yahoo.com wrote:

 Hi Rodger, just wanted to circle back. Thanks for the recommendation. I reached out to Eric @ Yellow Rose and he said they aren’t rebuilding the e34m5 compressor any longer as parts are hard to find. —- However, Michael @ acsolutiins.co said I could use their Sanden bracket & compressor as long as I remove smog pump (which I intend to remove anyway).