Engine Size: 400
Refrigerant Type: R12
Country of Origin: United States
After 3 different A6 compressors all leaked out the front seal, I found this forum and learned about the double lip seal (ACD 15-30948). I bought the complete master tool set and 2 double lip seals and went to work today. It was easy enough to get the seal in. Unfortunately when I went to pull a vacuum on the system, I could hear it leaking at the front seal. I then pressurized the system and could hear a faint leak under pressure. Completely bummed; I decided to pull out the seal and look at it. The darn seal has such a small step in it that my expanding tool can not get a grip on the seal. I pressurized the system to 70 PSI and still could not get the seal out. So now it leaks and I can not get it out - very bummed.
So I have 2 questions:
How do I get the darn DLS out of the compressor?
Has anyone had trouble with the DLS conversion? ANY IDEAS?
I must admit that I am concerned the the DLS needs a precision shaft for the lip to seal to. Maybe the shaft is not machined smooth enough to offer the DLS a good surface since it was not originally intended to be a sealing surface. "Dougflas" mentions that the seal may not seat immediately - but mine leaks so bad I can only pull 22"Hg with my pump. Should I run it without a good vacuum and see if it seats?
Edited: Mon June 23, 2008 at 5:42 PM by Rick Johnson
use a seal puller tool and it willl come out- or pressurize it again and push on it so it is certain to be flat in the snout- and it will pop out- I have done probably a dozen A-6s with the double lip- all have worked just fine- regardless of shaft wear. Did you use a shaft seal protector tool? to protect the seal from the shaft threads?-- is the new o-ring installed correctly- in the o-ring groove? Did you feel the seal seat properly when you installed it? Did you apply refrigerant (mineral) oil on the edge of the seal and on the teflon lips when installing?
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......
I feel your pain.
I have a 77 Chevy with an A6 that I have been trying to seal up. I installed 2 double lip seals and both leaked. I drilled two small holes in the metal part of the seal and screwed long screws in the seal. Then I put vise-grips on the screw heads to pull the seal. I have now put the old style seal back in and it is still leaking. This compressor wasn't a profuse leaker when I started this. I was doing major engine repair and the old A6 that was on the truck was a real leaker. The compressor that I tried the seals in was one that I had used in the past. It wasn't much of a leaker, but THOUGHT I would be wise and replace the seal. Is there another location on the front of the compressor where oil could be coming from?
I was going to question shaft wear plus the amount of rust and crude on the shaft, so where is the leak, between the seal and the shaft or between the housing and the seal? It's easy to have a twist in the O ring, can't have that.
A destructive means to remove a seal is to drill in a small hole, start a long dry wall screw, and jerk it out with a pair of vice-grips or even a couple of screws so you can pull it out evenly if all else fails.
Damn, I feel you guy's pain. I got a leaking A6. Its my 2nd new compressor leaking. I was thinking about trying to change the seal myself but after seeing this thread....I don't think I will mess with it. As much as I want to keep my car original, I think I will convert over to a Sanden compressor and shit can these pieces of shit A6s.
I'll say it again, Sanden compressors have shaft seal issues also. If you convert over to a different compressor I suggest a Seltec. GMTech has a lot of experience with shaft seals. If he says a double lip seal will work. I would take his word on it. If you send the A6 back to us I'll install a double lip seal in it. But I will not guarantee it won't leak again down the road.
""use a seal puller tool and it will come out- or pressurize it again and push on it so it is certain to be flat in the snout- and it will pop out- I have done probably a dozen A-6s with the double lip- all have worked just fine- regardless of shaft wear. Did you use a shaft seal protector tool? to protect the seal from the shaft threads?-- is the new o-ring installed correctly- in the o-ring groove? Did you feel the seal seat properly when you installed it? Did you apply refrigerant (mineral) oil on the edge of the seal and on the teflon lips when installing? ""
GM Tech, thanks for the response.
I did lube the seal and it was seated far enough to get the snap ring on. I did use the shaft seal protection tool. Tonight I will reseat the existing seal and use my stethoscope and try to determine if the leak is to the outer o-ring to seal or the inner shaft to lip seal. Afterwards I will try to pressurize the seal again to remove it. I hate to drill and create chips in such a critical area, but the seal design does not offer a flat bore to use my expanding tool on. Does the GM part number for the seal offer a better gripping surface for removal?
-If it is on the outer edge of the seal I will repostion the o-ring.
-If it is the inner shaft to lip seal leak - What do you think about the comment that you have to turn the pump 200 revolutions to seat the inner lip seal? I could pressurize the system with nitrogen and turn the comp shaft with a drill if it might help.
Edited: Tue May 27, 2008 at 3:37 PM by Rick Johnson
My leak check with a stethoscope was not able to determine if the leak was at the shaft or at the o-ring.
But when pressurized to 80 PSI there is no leakage at the seal. I rotated the compressor about 100 turns with an air tool and there was no leak. Now if I grab the shaft at the threads and pull it with about 40+ pounds of force, the seal will leak.
When I try to pull a vacuum there is a definite leak - I can only get about 18"Hg. If I push on the shaft threads with about 5-10 pounds of force the vacuum leak becomes severe.
This compressor has 1000 miles maximum on it. The shaft is definitely not extremely rigid - there is some slop. My fear is that with a ceramic face seal, shaft rigidity was not important. But with a lip seal, shaft rigidity and a centered location become more critical. Who knows what will happen when the shaft is spinning - it may center itself or it might bounce.
Do you guys with success use the GM or the Delco seal????
Should I gas up the system and see if it holds freon? I could always dump the moisture by purging the freon if the seal did not leak after a trial run.
Hopefully one of the experts who does this conversion regularly will add some comments.
Edited: Wed May 28, 2008 at 2:24 AM by Rick Johnson
The seal cavity is a dust collector anyway, always rust and tiny stones in there just should be cleaned out, like to use a blast of choke and carb cleaner, 400 grit sandpaper, another blast before removing the seal plus the shaft. Spur drill is best if nothing else works to pull the old seal, chips are minor, but also cleaned up first before removing the old seal. The O'ring groove has to be clean, a lot can be learned from removing the old O'ring, if chips are missing, they are in the groove.
Using a refrigerant compatible Nylog on the seal can work better on the O'ring especially on older stuff with even hard to see pits.
It's nice to get a perfect vacuum, but always doesn't work that way, the lip of the seal, seals a lot better with a strong back pressure, like a check valve, but negative pressure can tend to open that lip. Also with some wear, the lip tends to seat better. Kind of like breaking it in. But if you are feeling side play in the compressor shaft, the front bearing is worn. In operation, the lips will flutter and you will get leaks, time to look for a better compressor.
Little information from our remanufacture. All their A6 compressors come with the double lip seal. Any play in the compressor shaft will damage the seals and cause leaks. They said you may get away if a small amount of play with a ceramic carbon seal. We just pulled the hubs off both our vendors remanufactured and ALMA new A6.
As you can see in these images the one on the left has a ceramic seal and the one on the right a double lip seal.
I have also confirmed that you will need two different double lip seals depending on the compressor shaft.
21-34734 Ã¢ÂÂ MC-1148 measured the top of the can the ID is 18.25mm
21-34659 Ã¢ÂÂ MC-556DN measured the top of the can the ID is 15mm If a shaft is 14-15mm then you would use this seal. Anything larger you would use the MC-1148.
You cannot use the SK-771N (MC-1148) on all shafts. It is too big and it will not seal.
Mickey said that he measures the ID on the inside where the Teflon is.
MC-1148 Ã¢ÂÂ If the seal is OE it will have the GM number 6560844 stamped on the top of the can. This seal is mostly used for the late model HT/HU compressors.
Looking at the right hand picture I am somewhat surprised at what looks like crud and dirt inside the shaft housing. You can't even see one side of the snap ring. And the brown ring (a gasket of some sort?) looks quite cruddy also. Is this a fresh-off-the-shelf-never-installed unit from the rebuilder?
Are you surprised / concerned, or is this normal?
Just the effects of an image being taken. I still have the hubs off and double checked and it's perfectly clean inside. I have no issues with this remanufacture at all!!!!! Best in the business as far as I'm concerned. There are others which do a better paint job!!! But I don't care about paint jobs on compressors.
Good to hear. Thanks
We have had zero luck replacing seals at our shop. We don't even offer that anymore as it causes more problems than it solves. If your concerned about originality on the Firebird I recomend that you get a new A6 and get the correct stickers for the compressor from the specialty places that sell them for this purpose.
Just for the record, I did buy a new compressor along with the 2 rebuilds - all leaked. The important thing about the pictures that Tim posted is that a new compressor has the original 2 piece seal while his rebuilder uses the double lip seal. THIS IS HUGE. It proves that the double lip seal is a main stream repair! We just need to figure out what is going on with our individual installations. I believe we may have figured it out now that we know there are 2 different seals. I will pick up one of the smaller ones tomorrow and see if it solves my problem.
Edited: Fri May 30, 2008 at 1:45 PM by Rick Johnson
I picked up one of the smaller seals today. It will offer much more lip compression. I feel confident this this is the solution; we have been using the wrong seals. The parts store guy agreed.
The large seal offers .030 total interference - shaft equals .560, lips are about .530
The small seal offers .150 total interference - shaft equals .560, lips are about .410
I will have the results very soon!
Please change the description on the small seal page (21-34659). The page says Large Shaft seal and references MC-1148.
It should read something like, "21-34659 Ã¢ÂÂ Reference MC-556DN - the ID of the metal housing is 15mm. The lip seal measures about 10.5mm ID. If a shaft is 14-15mm then you would use this seal."
Note: the MC-1148 is the reference for the large seal (21-34734) according to your note above from your rebuilder.
Hopefully this will eliminate further confusion, and if it all works out - someone owes me a beer. (Never mind, I will be so happy to have a non leaking compressor that I will buy myself a beer)
Shit Rick.....if you can solve my leaking compressor problem, I'll send you a case of beer....
I promised to report my findings so here goes:
After about 3 weeks it started leaking. When I opened up the front I noticed oil puddling in front of the seal. I took out the seal and put in a new one using the larger of the 2 o-rings around the seal. It was a real bear to get in with the larger o-ring. After 2 weeks it has just started leaking. Needless to say the frustration builds.
I can't help but wonder if the surface finish on the shaft is too rough. Since the shaft was never intended to have a lip seal, they probably do not pay much attention to surface finish.
Damn that sucks Rick.....
Not the fix for the problem but..... Ecklers(Corvette resto parts) sells a pretty decent looking, semi-gloss black pulley cover for the A6 compressor. It will catch the oil and keep it off the hood. I am coming to the realization that A6s just leak, nothing you can do but keep dumping freon in em to keep cool As soon as I see the first drop of oil hit my hood again, I will be ordering the cover, as well as a set of gauges from TRB and some R134.....gonna learn how to start charging this stuff myself.
Maybe this is a stupid idea, but has anybody tried misting the seal with brake fluid after it starts leaking just to see if maybe that can swell it up for another few months?
Funny you all have leakage problems with the A6. My dad had a 1978 Impala with one and I had a 1979 Impala that had 3 of them in my time with it ( the second one was a lemon, the first one locked up) and a 1981 Caprice with its origional one and none of them leaked. The R4 in the 1981 though had a bad habit of leaking through the front seal. Guy finally just replaced it. Said he doesnt really have great luck replacing seals like that. The 1985 has been good that way though it is on its 3 one. Good luck to all of you.
2008 Chevrolet Impala LS
1981 Pontiac Bonneville
2007 Sears Craftsman Lawn Tractor
1985 Chevrolet Caprice
1986 John Deere 165 lawn tractor
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