The first time the o ring blew out I was at a car wash, I left the engine running and air turned on while I washed the truck, when I got back in the air was blowing warm. I checked for a leak with a detector and it was the o ring. I evacuated the system, replaced the o ring and recharged the system using a professional recharger, within a couple of weeks I was sitting in a parking lot with the air on and in about 10 min the same thing happened. It appears to be building up too much pressure when it is idling with the air on and the o ring is probably the weakest link in the system. Any ideas what it might be?

 

Are you talking about the seal for the manifold or the compressor seal.

 

The seal that is on the shaft of the compressor behind the clutch.

 

The replacement you use, is it neoprene or silicone.

 

I'm not sure it is in a kit from CarQuest Auto parts store.

 

I only ask because the 134A systems use a different lube oil than the older R-12. Maybe the O-ring used was not designed for the newer oil. Over pressure would of course blow out seals, your system should have a high pressure cutoff that should prevent that though. Poss a bent drive shaft on the compressor itself that wears out the seal prematurely. Sounds like a tough prob. Would hate to have to spend the $ to replace the compressor but you might have to end up doing it. At least it sounds like you have the tools and machines to do it right.

 

The kit is specifically for that year compressor..."97...where would I find the cutoff switch and do you know how to check it?

 

The high pressure cutoff is mounted in the line just below thw high side service valve.The low pressure switch is on the accumilator. Not sure how you would check it because it think it stays open until it is pressurized. I might be wrong though. I would check the book on it .

 

Well, I can replace the o ring, repressurize the system and then check it. I have checked the clutch with a laser light and it appears completly in round. It has been a tough problem to solve. As long as I don't idle the truck with the air on it works just fine while driving.

 

Could it be that the cooling system isn't up to par. If it started to get too warm that would raise your high side pressures some. I know that after installing E-Fans my A/C worked much better ( especally at idle) It also shuts down if I start to overheat. ( Have had the fuse blow on one of the two fans once. truck started running hot and first indication was warm A/C)

 

The truck never overheats, the temp gauge is pretty much rock steady even during an idle with the air on.

 

Hopefully someone else will have some ideas as I am stumped. Good luck... Pete

 

Uhm, there is no o-ring on the compressor shaft. It is a neopreme and metal type seal. It is held in with a C clip. Not quite sure what CarQuest sold you, but I work for a Ford dealer and we still can't get the front seal. Not to mention the special tool needed to change it. The only way to fix the problem as of right now, is to replace the compressor. If someone knows the part number for the seal and tool, please chime in because you will be helping me out as well.