What Sanden AC compressor do you recommend?

[PatinaBeforePolish]

This is the year of working AC. I have several NOS parts including a condenser so thought I would stay original and have the Bosch compressor rebuilt. So I sent it off to a well known rebuilder, Jay Stratton, and found there are internal parts that are NLA and it's not rebuildable. If anyone is thinking of using Jay for other rebuilds, he has a unique communication style that required about 10 email exchanges to get answers where 1 would have sufficed. Enough said.

So I'm going the Sanden route and staying with R12 as I have about 5 lbs of the stuff. I have a Wylie bracket adaptor. My question is, what Sanden AC compressor? There're a million of them but 709 keeps popping up. Thanks!!

[HB528i]

The 709 is the most popular Sanden I think. Jay lives not too far from me and has been invaluable in rebuilding steering pumps and steering boxes. He rebuilt an axial compressor like you describe and indeed there is one part that needs to removed to replace a seal and if it breaks you are screwed. Those compressors were also used in the Porsche 928. I also have the Wylie bracket in my e9 and e12, a work of art.

[tlake]

I have been using the SD508 Sanden unit since 2001, and it seems fine.

[maybeillbuyit]

Seems like most of the posts I see are for the 508. I'm planning to do this in the future,
https://www.acsolutions.co/en-ca/produc ... ersion-kit

[528i-1981]

It's not my place, Dave, but are you sure you want to use the OEM serpentine condenser? I would also be tempted to use a NOS condenser if I had one, but here's the deal - the OEM aux fan is loud and totally outclassed by modern fans (motor technology is way better today). So if you're going to use an aftermarket fan you'll need to work around the OEM condenser's peculiarities (some of the bracketing for the fan is permanent iirc). If you're going to upgrade your fan, then using a parallel flow condenser will be a better performer than the OEM serpentine condenser. And so fall the dominoes.

If you use the OEM fan, I would completely rehab the motor. Mine was drawing something like 28 amps and blowing the 25-amp fuse routinely. You can't later access the fan without pulling the rad and the condenser.

The Sanden has O-ring fittings, which any new condenser would also have. Fewer copper crush washers in your circuit is a benefit. You'll still have them at the drier and evaporator hard lines, but it's easier to get two big wrenches onto those joints from the engine bay (to seat the crush washers). Although I think the OEM condenser's fittings are fairly accessible with the grille removed.

I went through all of this decisionmaking last year, but my OEM condenser was shot. I also kept R12, but kept the original axial compressor after having it successfully rebuilt. One thing I definitely recommend is a crimping tool from Amazon to make your own hoses, especially with the mix of o-rings and crush washers and the new geometry of the Sanden.

Funny you mention Stratton, I swapped emails with him about a steering box earlier this year. He recommended I read books and study physics, evidently so I wouldn't ask such stupid questions. Lol. He pointed me to the real problem in my steering, so I have nothing but gratitude and respect for the guy nothwithstanding the gruff bedside manner.

[PatinaBeforePolish]

I've been told that R12 flows better with a non-parallel condenser. And having some R12 and a NOS condenser is taking me down this path along with a general consensus is that R12 blows colder. And I want to avoid fabricating brackets for a universal condenser although it looks like the ACsolutions condenser has a universal fit. If R12 doesn't work out I believe I could switch to 134 as I'll have a Sanden compressor and upgraded hoses and would only have to upgrade the condenser. Interestingly, the independent I'm working with who's a 45+ year BMW tech tells me they never used the copper crush washers when working on the systems back in the day. Says the connections seal tighter without them. Thanks for the fan advice, I'll have to test the draw on mine. I think a universal fit will work fine and have had success with the Spal brand.

As for Stratton, he told me "You should not be involved in anything related to auto repair". Apparently one must perform a forensic analysis of instructions on his website before attempting to use his services. I'm sure he does nice work but geez.

As always, working on vintage BMWs is almost as enjoyable as driving them. The advice here is always greatly appreciated!

Jon

[cory58]

I bought brackets from Layne in 2022 for the M20 and M30. I immediately installed the M20 bracket on one of my E30s and put the M30 bracket on the shelf, just in case I need it someday and Layne is no longer making them.

He recommended the Sanden 709 for the M20. Layne is great to work with. Why not just contact him and ask the question?

Cory

[528i-1981]

Jon - sorry I thought Dave started this thread. I used a Vintage Air 14x20 universal fit, and that went in without much fuss with bracketry. Fitting the fan required a little more experimenting with various hardware. Altogether not a difficult job, but I agree with you that the OEM setup eliminates all these issues. I'd not heard that serpentine condensers work better with R12, but again if I had a NOS OEM condenser I'd have used it. The parallel flow works fine without icing up so overall I'm satisfied. Having AC is great.

R12 is pretty fabulous. I plan to keep running it as long as possible.