Pfc. Parts

Hello list. I took my '85 in to have the A/C system checked today and found out it has a leak on the top side of the compressor. I have no reason to believe the compressor itself is faulty, the mechanic working on the car just told me he'd discovered a leak "on the top side of the compressor".

I guessed this might happen since the car had been in storage for a very long time. I expected most of the o rings were shot and perhaps some of the rubber hoses.

Pelican lists 2 o-ring kits (front and rear) for this year, are there any other parts that should be replaced during a refresh like this?

I couldn't find anything with a search on "AC air conditioning rebuild" so I'm including those keywords in this post for future reference.

Thanks,

j.kenzie@sbcglobal.net

Hi Scott,
You can have o-ring leaks in several places on your compressor. You can also have a shaft seal leak. You might have either or both. A leak detector or UV dye can help localize the leak, and then it is a question of replacing faulty parts with new or reconditioned. It's a slippery slope when you start replacing all the o-rings and a few other parts, but addressing a known leak sounds like a great place to start. BTW do not use any leak sealer products.
Good luck,
Dave

ammonman

To do the full job you should replace both expansion valves, the receiver/drier, all the o-rings, have the hoses rebuilt with modern barrier hose, reseal the compressor with new o-rings and shaft seal, and flush the condenser and both evaporators to remove all the old oil before filling with the correct amount of the right oil for the refrigerant you plan to use. Once all that is done triple evacuate, breaking the vacuum each time with refrigerant so as to absorb any moisture in the system before doing a final evacuation and dropping in the correct amount, by weight, of your refrigerant of choice.

Mike

Pfc. Parts

Dave, is this something that I can do without a fancy A/C vacuum system? The problem here is I don't have one and my local shop charges $90/hr to hook theirs up (not to mention a 2 hr round trip for me to their shop and the cost of pizza while I wait for the test. It goes without saying that pizza has a cost that can't easily be expressed in dollars).

If I can partially fill the system with a UV dye/refrigerant and trace it in my shop it makes sense for me to take on this project, else it seems best to just sub the whole thing out.

I understand. So rather than do a wholesale refresh of every rubber hose, o-ring and seal in the entire system, I'd best focus on what's broken and leave the rest alone; the old "if it ain't broke don't fix it" rule. I am a little concerned though since every rubber part, o-ring or seal in this car is 30 years old and most of them haven't been lubricated properly for at least 15 of those years.

Thanks for the advice,

Pfc. Parts

Mike, that's what I was looking for; a description of a complete, thorough refresh. I'm going to assume the hoses, compressor, evaporators and condenser should be removed, flushed with A/C solvent and replaced. In other words this is not a cleaning project that takes place on the car?

Regards,

j.kenzie@sbcglobal.net

I have had pretty good luck with dye. You should see spatters of dye near a leak area. A pro shop should be able to localize, and repair, with some kind of discount for the diagnostic time if you pay for the repair (maybe?) Our compressors are kind of buried and you may have ambiguous results, then you might be smarter to let the shop make the call and warranty the results.
BTW are you running R12 or R134a? It makes a difference in cost and approach.
Dave

Pfc. Parts

Dave - I'm using R-12 which of course is not cheap. Seeing the top of the compressor is a little difficult without removing a few things, but I've done all that before and I need to repair a broken belt tension sensor cable anyway so that isn't intimidating. The main question is-- can I inject dye and (something else, perhaps A/C oil) into the compressor intake side and use it alone to pressurize the system and cause a leak, or do I need a very expensive A/C vacuum system to do it?

Pfc. Parts

BTW, I'd like to mention this is a practice run. I plan to completely remove (and never replace) the A/C system on my track car so going through these motions on the street car is not wasted effort.

Fogey1

Here's a mess of AC threads:

https://rennlist.com/forums/928-foru...se-inlets.html
a/c compressor hose inlets.

https://rennlist.com/forums/928-foru...a-c-hoses.html
who can rebuild a/c hoses

https://www.928gt.com/t-wallyhvac.aspx

http://members.rennlist.com/sharkski...AC-Chillin.htm

https://rennlist.com/forums/928-foru...ting-cold.html

https://rennlist.com/forums/928-foru...r-removal.html
A/C Condenser Removal

https://rennlist.com/forums/928-foru...ac-system.html
O-rings for AC system

https://rennlist.com/forums/9711682-post2.html
Buy a HF kit with the green O-rings for less $10 and you'll have all the seizes you'll need

https://rennlist.com/forums/928-foru...c-o-rings.html
What sizes are these AC O rings?
https://rennlist.com/forums/928-foru...ml#post9670123

http://www.nichols.nu/tip736.htm
Climate Control
R-134a Conversion O-Ring List

https://rennlist.com/forums/928-foru...ll-method.html
AC Refrigerant Fill Method

Pfc. Parts

Fogey - Thanks! I really did try before starting a new thread, I must have used the wrong words.

Regards,

Pfc. Parts

Fogey - again thanks, I was wondering what keys you used for this search? Did you use the "Advanced Search" on Rennlist or Google it? It would be good to know how to use this thing in the future.

Regards,

ammonman

When I did the refresh on my 1990 S4 I flushed the condenser and front evaporator coils in place. I went to the local home store and bought some lengths of various diameter vinyl hose and gently hose clamped adequate lengths to the coil inlet and outlet connections. This allowed me to introduce cleaning solvent to the coils and blow the oil and solvent mix out with compressed air and direct/control the spray. I put the "discharge hose" end into a small bucket and then packed the bucket with rags to contain the resulting aerosol. Even taking this precaution I made sure to have LOTS of ventilation. I flushed each coil multiple times both directions to try and ensure that all the old oil and sealant someone put in the system to try ad correct a split hose at the rear evaporator was removed. As far as the compressor goes just try to pour/work as much oil as possible out. Even if you open the unit to replace the shaft seal and case o-rings I wouldn't flush the unit with solvent. Just pour out as much oil as you can while its apart and rinse the exposed parts with clean fresh oil. Once you have it back together you add the correct amount of clean new oil (the right oil for your refrigerant of choice) to the compressor via the suction inlet and re-install it. As far as getting the hoses rebuilt, talk to one of your local places that does mobile A/C work. They should have the necessary bulk hose, ferrules, crimping tools, and expertise to rebuild the hoses good as new. There are pretty good videos on YouTube that show how to replace the shaft seal and re-seal the case.

Mike

fraggle

I've heard that using air-brake system cleaner from a truck stop supply does a great job cleaning everything inside and keeping the moisture down. I'd recommend buying the harbor freight pump and gauges, I did this and things worked out great on my car. If you have rear AC test test test before you put in R12 or you'll be sad when it all floats away.

z driver 88t

FYI if you need to DIY with R-12 you can take an on-line test for cheap (around $24-$30, IIRC) to get your 609 certification that will let you order R12.

I finally went with an R134 conversion kit (new modern compressor, hoses, drier and custom bracket)from Griffiths and have been happy with it, but for years I just bought a few cans of R12 every year to top off on EBAY. Just required a 609 certification.

dr bob

Based on the experience of one here, I highly recommend that folks chasing leaks look closely at the R-134a conversions for their S4+ cars. There's enough condenser and enough fan capacity to make this a very worthwhile conversion. I get center vent temps below 20º with fan on 2, 90º+ ambient here in the Los Angeles area, under 2000 RPM cruising. It's cold enough to freeze fingers on the steering wheel. The annual use pattern here requires AC pretty much every month, with some months a little more important than others. So the system gets a workout.

The work is the same required to leakproof the R-12 system if you haven't frag'd the compressor already. You can use the Griffiths kit and get everything in one package, or buy the required pieces from your favorite vendor.