Automotive Air Conditioning Information Forum (Archives)

Provided by www.ACkits.com

We've updated our forums!
Click here to visit the new forum

Archive Home

Search Auto AC Forum Archives

V-5 Compressor Reseal--Catastrophic Failure

JLHAWKINS on Thu August 27, 2009 11:47 PM User is offline

Year: 1997
Make: Olds
Model: Cutlass Supreme
Engine Size: 3.1
Refrigerant Type: R-134A
Ambient Temp: 89
Pressure Low: 27
Pressure High: 235
Country of Origin: United States

I posted about this vehicle several times. The V-5 compressor had a "belly leak". Chick and GM Tech gave me tips, diagrams and even a video on replacing the case O-rings and shaft seal. I ordered the gasket kit, shaft seal kit and shaft seal installation/removal tools from AMA.

With their tips and suggestions, the disassembly was fairly easy. There was corrosion around the case O-rings just like they had stated it would be. With the shaft seal removal tool, the seal popped out easily. Remarkably, the OEM shaft seal with 90K miles wasn't leaking. The interior of the compressor was perfectly clean. I cleaned the corrosion. reassembled the compressor, added the same amount of new oil back to the crankcase as I had drained out plus about 1/2 once for "good measure". I pulled a deep vacuum for about an hour, watched the vacuum for about 1/2 hour (no drop) then vacuumed again for about another 1/2 hour. I charged 30 oz of refrigerant straight into the vacuum. Cooling performance was excellent with vent temperatures in the low 40's.

This performance continued for almost two weeks. Today my wife informed me that the vehicle was blowing hot air. I tried it thinking it was maybe her and the dual Climate Controls but it wasn't. Upon raising the hood, all kinds of compressor oil had slung out the front of the compressor onto the undercarriage. This oil was not there a couple of days ago when I checked the other fluids and looked at the belly area of the compressor to see if the O-rings were holding which they still are. I experienced some type of catastrophic shaft seal failure.

While changing the shaft seal, I noticed several things that seemed kind of strange. First when I removed the OEM seal, there was no O-ring behind it. On the video's and photos posted on this forum, an O-ring is always there. Second, the O-ring that came in the new seal kit was approximately 1 3/8 in in diameter. The bore in which the seal resides is only approximately 1 1/4 in. in diameter. Thus when the 1 3/8 O-ring was placed in the 1 1/4 bore, it "wadded"up. I cut the O-ring off until it would just fit in the bore and reattached the ends. Third, it took alot of force to ever get the seal down deep enough in the bore to reinstall the new retaining ring. Once assembled, the compressor turned very freely.

As I think about what happened to cause this failure, my thoughts go to the O-ring in the kit. After I cut it to just fit in the bore, that meant that the metal portion of outside diameter of the seal was hitting the O-ring this making it difficult to seat. I still have the seal I removed and looking at its construction, it would seem with the replacement seal, the O-ring should seal on the back surface inside the diameter of the metal portion of the seal. The thickness of the O-ring appeared to be about the right thickness to provide a seal between the back of the seal and the compressor case. I think my O-ring was too large, the metal portion of the seal cut the O-ring and it later blew out. I will order another kit from AMA and try again. Perhaps when someone made up the seal kit, they placed the wrong O-ring in the package.

Chick, GM Tech and others, could you give me your thoughts on this occurrence? Tim, you might want to check those shaft seal kits for small shaft V-5's. There is no way a 1 3/8 in diameter O-ring should be provided for installation inside a 1 1/4 in diameter seal bore.

Thanks in advance for your help in this matter.

Chick on Fri August 28, 2009 7:21 AM User is offlineView users profile

You must have missed the O ring around the seal, the inside of the "snout" is grooved so it fits in there and can't move once the seal is against it.. And since you cut an O ring to fit, it must've been a hard job getting the seal in.. But you also need to see if the snap ring seated properly with the extra O ring in there... You usually need a pick to get the old O ring out, then the groove becomes apparent... Hope this helps..

-------------------------
Chick
Email: Chick

---------------------------------------------

Freedoms just another word for nothing left to lose

GM Tech on Fri August 28, 2009 8:17 AM User is offline

Never, ever cut an o-ring to fit-- it just will never work- there was an o-ring in the OEM set-up- don't say there wasn't.... it would have never have sealed from day one without one-- you just did not see it-- you have to look real hard to see it snuggled up in the "O-ring groove" of the front head. Like Chick says, you have to use a dental pick to get the old one out- then the new one will slip right in- and the shaft seal will slip in and seat itself very easily. The o-ring seals on the OD of the shaft seal and on the ID of the o-ring groove of the front head- it is not used like a gasket- is not sealed by force of the snap-ring- it seals by 19% interference OD to ID. It is a miracle that your compressor sealed as long as it did- heck, I have forgotten to put a snap ring back in- over the shaft seal- it lasted over a year before the seal finally blew out. At least the good news is, that there is an easy fix-- just learn from this mistake and go on.

-------------------------
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......

JLHAWKINS on Fri August 28, 2009 8:58 AM User is offline

Thanks Chick and GM Tech. I guess I missed that original O-ring, thought there should have been one in there but didn't look close enough. Also thought something was strange that it took so much force to seat the seal. I will order another seal kit from AMA and try to get it right this time.

One other question--the O-ring provided in the seal kit was about 1 3/8 in. outside diameter while the seal bore is only about 1 1/4 in inside diameter. Was an O-ring of that diameter the correct size for this application?

Thanks for your help. I knew you would know what I did wrong if I went into enough detail for you to understand what I did.

GM Tech on Fri August 28, 2009 9:41 AM User is offline

Do a direct comparison to the one you take out-- use the one that is the same size as the one you use your dental pick to take it out...the one you can't see because it is in the O-ring groove of the front head.......

-------------------------
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......

daman on Sun August 30, 2009 12:59 PM User is offlineView users profile

Some times O rings need to be a snug fit,, "wad" up for a tight seal fit,good luck this time.

-------------------------
'00 Pontiac Sunfire 2200 I4 SFI
'99 Chevy 4x4 Z-71 5.7 Vortec v8 CPFI
'97 Chevy 4x4 6.5 Turbo Diesel 2500
'95 Pontiac Grand Am GT 3100 v6 SFI
'88 Chevrolet Camaro IROC 5.7 TPI(49,000 original miles)

Edited: Sun August 30, 2009 at 12:59 PM by daman

SpinRite on Sun August 30, 2009 1:25 PM User is offline

This has been a very interesting thread, and I have learned some good lessons from it about "hidden" O-rings.

I always assumed that it wasn't possible to fix a wrong-sized O-ring, but it sounds like you have a way to do it:

q]Originally posted by: JLHAWKINS...I cut the O-ring off until it would just fit in the bore and reattached the ends. ...


Could you explain to this newbie just how to do it, please?
Do you cut it straight across, or diagonally?
If diagonally, is it better to cut parallel to the axis of the ring, or perpendicularly?
What is used to glue the cut ends of the O-ring together?

Thanks for the help.

daman on Sun August 30, 2009 1:31 PM User is offlineView users profile

Quote
Originally posted by: SpinRite
This has been a very interesting thread, and I have learned some good lessons from it about "hidden" O-rings.



I always assumed that it wasn't possible to fix a wrong-sized O-ring, but it sounds like you have a way to do it:



q]Originally posted by: JLHAWKINS...I cut the O-ring off until it would just fit in the bore and reattached the ends. ...

Could you explain to this newbie just how to do it, please?

Do you cut it straight across, or diagonally?

If diagonally, is it better to cut parallel to the axis of the ring, or perpendicularly?

What is used to glue the cut ends of the O-ring together?



Thanks for the help.

Quote
Originally posted by: GM Tech
Never, ever cut an o-ring to fit-- it just will never work!!!


-------------------------
'00 Pontiac Sunfire 2200 I4 SFI
'99 Chevy 4x4 Z-71 5.7 Vortec v8 CPFI
'97 Chevy 4x4 6.5 Turbo Diesel 2500
'95 Pontiac Grand Am GT 3100 v6 SFI
'88 Chevrolet Camaro IROC 5.7 TPI(49,000 original miles)

JLHAWKINS on Mon August 31, 2009 10:34 PM User is offline

This is in response to the inquiry as to how I cut down an O-ring and reattached the ends.

First I do not condone cutting O-rings to a different size if the correct size is available but in a "pinch", it can be done. I learned this from my now deceased Father.

Basically if you wanted to cut an O-ring with an outside diameter of 1 3/8 " down to a 1 1/4" diameter like I did in this instance, first you subtract the difference in diameters. Take this difference, in this case 1/8", and multiply it by pi (3.1416). This is the amount you want to remove from the circumference. Lay the O-ring on a flat surface and cut it perpendicular to the circumference. After this cut, make another cut removing the amount determined above. This cut needs to be perpendicular to the circumference also. Now take a drop of Super Glue and place on both ends to be joined. Place on a flat surface and hold the two ends together for a few moments and now you have a smaller O-ring. Of course for it to work, the thickness of the O-ring being cut down has to be correct. The Super Glue will make a permanent bond between the two ends. When my Father first did this I was skeptical of the Super Glue bond but evidently Super Glue like the material most O-rings are made from. Try it sometime just for fun to see if it works. It does.

This procedure may not work on A/C applications where high pressure gases are involved but it has worked on several hydraulic applications. However, my problem was not the cut-down O-ring but rather one too many O-rings.

HECAT on Tue September 01, 2009 6:13 AM User is offline

Super Glue does not flex like the rubber when cured, they make special glues that correspond with the material (chemical resistance) and durometer (hardness) being used.

Following the manufacturers instructions, I once used a spliced o-ring to get a log skidder out of the swamp and onto a low boy; to bring it into the shop and install the proper parts that were on order. I had to replace the spliced o-ring 3 times to get this machine moved a couple of hundred feet. Splicing o-rings can be another one of those lessons on frustration.

IMHO with just a little fluid power history in my past; I would not use a spliced o-ring in any application other than maybe around the outside of a cup holder insert to stop it from rattling.

-------------------------



HECAT: www.hecatinc.com You support the Forum when you consider www.ackits.com for your a/c parts.

FLUSHING TECHNICAL PAPER vs2.pdf 

Back to Automotive Air Conditioning Forum

We've updated our forums!
Click here to visit the new forum

Archive Home

Copyright © 2016 Arizona Mobile Air Inc.