Mongo

Back in 2008, another Rennlister tried to help me get the AC working. We pumped some R12 in the system and the compressor kicked on, blowing ice cubes in the car. Then, after shutting it off, an audible hiss could be heard coming from just behind the compressor clutch and pulley. Front seal went bang due to age. The compressor hasn't been used since.

So here I am 10 years later and the weather is heating up and I'm feeling daring enough to tear it apart to R&R it. To those who have rebuilt their own compressors, what are your experiences and recommendations?

Rob Edwards

Not that complicated, and Griffiths has a nice re-seal kit for the 6E171. Trickiest bit is getting the shaft seal on without scratching the lip, and setting the gap on the clutch.

https://griffiths.com/product/porsch...e171-seal-kit/

V2Rocket

I used that kit on my old 6E171 years ago, compressor comes apart pretty easily.
Probably my installation error of the new parts, because the fix didn't last so I just bought a new compressor.

Michael Benno

545svk

I did mine. It worked well afterwards. Just took my time and asked when I got stuck,
https://rennlist.com/forums/928-foru...ood-bad-2.html

FredR

Has it been cold in SFX for the last 10 years?

Replacing the dynamic seal is not too difficult but the question must now be whether the internals are ok after being sat for that amount of time with no gas and the possibility of air based moisture migrating inside. A good inspection should reveal all. At the very least you will also need to replace the body seals as well.

It surprises me that you could tolerate not having the a/c system working for such a long period of time for want of a relatively simple repair. To be fair, I love driving my 928 with the windows open when ambient conditions allow [not many weeks of the year I can assure you]. Maybe it does not get too hot in the SFX area during summer- I assume it does?

RET

The actual rebuild process is pretty simple, just make sure everything is very clean and replace all of the o-rings and case seals. The receiver/drier should probably be replaced.

Mongo

Fred I don't know how I tolerated it all this time actually. Then again none of the 944s I owned before the 928 ever had an AC system working either. I guess I got used to it.

I think I will go the route of the rebuild, but also replace as many O-rings as I can get my hands on, including replacing dryer, and the expansion valve (do I need to replace the one for the rear AC too?)

Michael Benno

Taguid

I know you want to rebuild it but I say just buy a new compressor and be done with it.6 months ago, I bought a new Denso and had all the hoses rebuilt with barrier and replaced all the orings, expansion valves, and receiver drier. It has worked flawlessly since. Also, if you are sticking with R12 and it doesn't seal up properly that alone will make up for buying a new compressor. Just saying it might save your sanity.

Mongo

I'm converting to R134a. Just too difficult to refill with R12 myself.

Rob Edwards

Hmm. An r134a retrofit is way more work than refilling with R12.

Mongo

I have lots of R134a in my garage. Just not worth the trouble to drive to a shop and get it refilled. Considering my compressor had R12 run through it, I'll just cough up the money and buy a new one, replace the expansion valves and dryer.

Rob Edwards

That's a good start, but since you were running R12 before, your system had old-school Denso ND-6 mineral oil in it. Since r134a is immiscible in mineral oil, you're going to want to get as much of the old oil out as possible, or you're walking the tightrope of too much POE (ester) oil (to prevent starving the compressor but decreasing cooling capacity) vs. too little (vice-versa). And ester oil is more hygroscopic than mineral oil so you'll want to pull a good long vacuum on the system before replacing the drier and adding your new compressor and drier. Do you have access to a good vacuum pump and gauge set at home?

V2Rocket

this one should work if you swap your 928's pulley onto it.

https://orangecounty.craigslist.org/...599645859.html