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A/C is in...but there is a leak somewhere

I

Indycanard

Member
Well, after a couple weeks installing a Sanden type compressor with condenser, I have a leak. It took FOREVER to drill the two 1-1/4 holes thru the radiator support AND the two 1-1/4 holes thru the firewall. I burned out 3 cheap Harbor freight hole saws. I finally got a good quality bi-metal hole saw, and the metal cut like butter on the last hole. Anyway, I installed all the hoses, and tightened up all the joints. I connected my A/C manifold gauge set and sucked the air out with my vacuum pump. I could tell the pump never really got the air all out. I have a leak somewhere. With the pump closed off, the vacuum bled out after 120 seconds, may a little more than that.
I really would like to have a sealed system and sucked out for a couple hours if possible. I can find a leak once pressurized with the leak dye in the freon, and I have a black light. Is there anyway to find a vacuum leak? I guess I could pressurize with a little freon just to leak check, then evacuate again to get all the moisture out.

Any ideas?
 
I would go thru and loosen and reposition each fitting and retighten. Then vacuum again.
 
I did loosen and re-tighten many of the joints that I thought would be the culprit, but I guess I didn't get the right one. I will systematically loosen and re-tighten each one tonight. I was thinking maybe I forgot a o-ring. As far as I could tell, only the two connectors on the pump used o-rings, all the other joints were flared. Does that sound right? I just don't want to over tighten a coupling to the point of stripping the threads. I sure hope all the components (evap, condenser, dryer and pump) are leak free. Is there a dye only can (with inert gas) that I can pressurize with to leak check?
Thanks for the advice..
 
No way that I know of to leak test without freon. Just be gentle with the fittings. I have seen them leak from being to tight.

I wounder if you could run the vacuum and apply some liquid to each joint, one at a time, and look for it to be sucked in.
 
You could pressurize the system (don't need much pressure ~20psi) and use kids soap bubbles or something similar to find the leak. kip
 
I think I will re-seat all the connections and check again, and if that fails, I'll use my air compressor to inflate to 10 psi. My compressor air should be dry, I have a water separator in-line. I have some "official" Leak-check solution and I can hit all the joints, or a mechanics stethoscope to check the evaporator/condenser/pump. I'm hoping for just a bad connection.
 
LEAK FOUND!

I pressurized the system to 30 psi and the leak was obvious. The witness hole on the sight glass hose had a blast of air shooting out. This hole is in the crimped cap on the sight glass end of the line. I put my finger over the hole and the leak stopped. A bit of good old duct tape, and I evacuated the system again. The vacuum held. It did eventually bleed down just a bit, but I'm sure the bad crimp on the sight glass hose may also leak-out thru the end of the cap also. What sucks is I have to wait for CJ Pony Parts to ship a good hose. Hopefully they will drop ship from the west coast.

One delay after another. boo
 
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