55 A/C repair

[old-tank]

After returning from South Bend I noticed a new oil leak at the right front (I know, it's a Buick). Turns out it was the a/c compressor leaking oil. The compressor was an old unit that I cobbled together 95,000 miles ago from a couple of seized units (and who knows how many miles total it was used). After I got the belt off I noticed lots of play in the front shaft. I tried to find a NOS or good used compressor (actually did find a NOS 56 compressor in the original shipping box, but did not have a clutch to fit --- keyed shaft vs splined shaft on a 55)( and found 2 used ones locally that were full of rust). After finally locating a bearing for the front of the case (the bearing was a close fit, but not exact and that made it necessary to install and remove shims over and over after pulling the bearing off the shaft. Seal replacement has been detailed on my website (BuickRestorer in my profile). Following are some pictures of the 'innards':

First pic is crankshaft with pistons/rods; second is assembled in cylinders; third is the case; fourth is leak testing; fifth is front without coil, clutch etc; sixth is oil pump parts.

I will not detail the procedure, I will not know you or how to do it if asked...you don't have enough money to pay me...on the other hand you should try this since your are no better than me;)

It is installed on the car, a vacuum is being applied now...refrigerant to be installed when cooler.

Updates later....

(outside temps range: 82-102...gotta sweat to be cool)

Willie

[Fr. Buick]

You lucky guy, at least you can find replacement front seals!!! No such luck on the '54 and prior.

Congratulations, Willie, I admire how you get your hands dirty and get it figured out.

[Buicknutty]

Where did you find the NOS compressor, I need one for my '56.

Keith

[old-tank]

Where did you find the NOS compressor, I need one for my '56.

Keith

Local club member has it. $400 and well worth it. Contact me (PM) for info.

Willie

[avgwarhawk]

Quite a complicated set up of tiny pistons.

[Guest gksullivan]

I had the compressor and other A/C parts rebuilt on my 56 Super about 10 years ago. It ran cold for a couple of years but then the R12 leaked out. It was too costly to replace the R12 and I suspect it would not convert to a newer refrigerant very well. Anyone had any luck with doing this? Gael

[avgwarhawk]

I don't see why it would not convert well. Different refrigerant and oil. Different low and high side connections for adding refrigerant and confirming correct pressures. Same concept. I have converted older R12 systems in cars from the late 80's.

[TexasJohn55]

Search the forums for r134 conversion, I'm sure there has been alot of them converted. I would expect similar results as other years that have an expansion valve setup. If search does not produce what you need, start a new thread on that issue.

[TexasJohn55]

I would bet that Willie's is r134 and could address that. Or buick5563, or.........?

[Guest gksullivan]

Thanks, guys! Glad to hear that it's possible. Not something I'll do right away will contact those you suggested and post when I get into that again. Gael

[old-tank]

R12 is the gold standard that has excellent performance in these old systems (55 rear evaporator) and that is what I have used. When I rebuilt the compressor I could not find any original mineral oil for the compressor so I installed ester oil which is supposed to be compatible with all refrigerants and mixes with remnants of mineral oil. Although I had info from others with 55 factory air that R134a did not work well, I decided to try it... and they were right: pressures much higher and outlet temps in the low 50's. Next I will try R152a (do your own research and draw your own conclusions) and will report back.

Mike (Buick5563) installed ester oil in his 55 factory air and tried Enviro-Safe with poor results (calls to tech support told us that we should use the 'industrial formula'==>more $$)...the msds for Enviro-Safe says it contains alkanes (probably propane or equivalent; highly flammable); he then installed Johnsen's Freeze12 with marginal results (this product is no longer being made....still some available on ebay = $$$); next R152a was installed and it seems to be working well with outlet temps in the low 40's and pressures actually lower that R12.

Willie

[Guest gksullivan]

Sounds like the R152a should do the trick. I had some guys in Florida do the compressor rebuild (Old Car Air?) so they may have some helpful info. What I will need to do is to redo (again) is the hot gas bypass valve. When they last charged the system they put dye in with R12. I have a "Halloween" blacklight and when it had leaked out I could see the dye was all over that valve. I think they make some sort of syrupy sealant for these situations that may do the trick. Also the blower motor doesn't seem to blow hard enough so I need to work through that too. Oh well, if I just had more time and $$. Gael

[buick5563]

Personally, I pulled that valve completely out of my system and blocked the line. It worked in my case, rather than repairing it.

The fan motors are a pain to get out, so check to make sure you have full 12 volts at the motors first.

****Gael,

Disregard this. My suggestion worked on my 55, which is completely different than your 56.

Edited August 25, 2013 by buick5563 (see edit history)

[old-tank]

I finally got the details worked out. The 55 system uses 88 oz of R-12 and based on the difference in molecular weight of R-152a vs R-12 52% should be equivalent. Anyhow I put in 40 oz and the cooling was marginal, but the return line was frosty at the compressor as was the compressor body :eek:...apparently too much. So I started over: 12 oz was cooling pretty good (50* at outlets vs expected 40*) and the return line was cold only for a few feet; another 12 oz and the return line was cold back to the compressor, but the compressor body was warm as expected and the outlet temp was 40* (the liquid line is half full vs full for R-12). A 20 mile run a few minutes ago (105* outside) and it cooled like R-12. (So much for 'calculations'...it's alway better to be lucky than smart )

I was worried about the viscosity of the ISO 100 ester oil vs the 525 vis mineral oil...apparently they are directly equivalent, just different nomenclature (like english vs metric)

Time will tell if it is a good long term solution, but the performance is good and the cost for 24 oz is about $10 vs $200-400 for 88 oz of R-12... and it is more readily available.

Willie

[bhambulldog]

Cool!

[TexasJohn55]

Cool indeed! Now that is some useful information. Thanks Willie for sharing that with us.

[therios]

While researching information about R152a (as Willie suggested ), I came across a discussion thread on the LeSabre T-type Forums (The Lesabre T-type Forums • View topic - Air conditioner Repair - Refrigerant R152A - Duster Spray) that included a link to this Youtube video (Air Conditioner Charge - HFC152A "Duster" Refrigerant - Accumulator explained - 1986 Buick Century - YouTube) explaining and demonstrating an A/C system conversion to R152a. (The guy who made this video goes by the handle "turbokinetic" on the LeSabre T-type Forums; maybe he's also active on this forum?)

A very interesting part of the video comes at the end when he explains how the accumulator (dryer) works, and why it's necessary to replace the accumulator when converting an A/C system to a refrigerant that requires a different lubricant.

Pretty cool video. (No pun intended.) Edit: OK, I lied. Pun intended.

Ike

R12 is the gold standard that has excellent performance in these old systems (55 rear evaporator) and that is what I have used. When I rebuilt the compressor I could not find any original mineral oil for the compressor so I installed ester oil which is supposed to be compatible with all refrigerants and mixes with remnants of mineral oil. Although I had info from others with 55 factory air that R134a did not work well, I decided to try it... and they were right: pressures much higher and outlet temps in the low 50's. Next I will try R152a (do your own research and draw your own conclusions) and will report back.

Mike (Buick5563) installed ester oil in his 55 factory air and tried Enviro-Safe with poor results (calls to tech support told us that we should use the 'industrial formula'==>more $$)...the msds for Enviro-Safe says it contains alkanes (probably propane or equivalent; highly flammable); he then installed Johnsen's Freeze12 with marginal results (this product is no longer being made....still some available on ebay = $$$); next R152a was installed and it seems to be working well with outlet temps in the low 40's and pressures actually lower that R12.

Willie

I finally got the details worked out. The 55 system uses 88 oz of R-12 and based on the difference in molecular weight of R-152a vs R-12 52% should be equivalent. Anyhow I put in 40 oz and the cooling was marginal, but the return line was frosty at the compressor as was the compressor body :eek:...apparently too much. So I started over: 12 oz was cooling pretty good (50* at outlets vs expected 40*) and the return line was cold only for a few feet; another 12 oz and the return line was cold back to the compressor, but the compressor body was warm as expected and the outlet temp was 40* (the liquid line is half full vs full for R-12). A 20 mile run a few minutes ago (105* outside) and it cooled like R-12. (So much for 'calculations'...it's alway better to be lucky than smart )

I was worried about the viscosity of the ISO 100 ester oil vs the 525 vis mineral oil...apparently they are directly equivalent, just different nomenclature (like english vs metric)

Time will tell if it is a good long term solution, but the performance is good and the cost for 24 oz is about $10 vs $200-400 for 88 oz of R-12... and it is more readily available.

Willie

Edited September 8, 2013 by therios (see edit history)