Hi fellas

It's been a while since I posted on this great forum, I still see a lot of familiar names, and I visit frequently to read up on interesting issues, however I've been busy with other projects, and my Benz gets reduced attention these days.

I'm here seeking advice as I'm faced with a difficult problem.
I've been working away on my 1985 190E 2.3 fixing and rebuilding components, and I'm at a stage where I want my AC working, since I'd like to drive the car during summer time. I set out to resurrect the system which has never worked while the car was in my possession.

I started out by doing a compressor rebuild. Amazingly it looked really good from the inside, no rust, everything clean, one piston had a few small scores, but I'm not considering a new one yet until I see how this one performs. All orings replaced, new condenser, even though the old one didn't leak, it was rotted, and it's days were numbered, so I replaced it. New drier, not installed yet. I got a vacuum pump and gauges too so I can service the AC on my other cars as well.

So, I put everything back together, and pulled a vacuum, things looked good, but after a few days the system sprung a leak, and now after about 30 minutes, all the vacuum vanishes, so it's a big leak, but not big enough to easily find.

I set out to search for a DIY way to find this leak. I tried filling the system with compressed air and spraying things down with soap and water solution to see if something would show. This should work, but not everything is accessible, so I did not find the leak this way so far, I keep trying but this might not be an optimal way.

My next option is a UV leak kit, this should work, but I would have to load up the system, and run the compressor before all the refrigerant escapes. Problem with this approach is I don't know if I won't be doing damage to any of the components by forcing the system on, if it even starts, but I am considering it, I just need to do a bit more wrenching and put everything back together before she starts up.

I heard of a way to use nitrogen to find leaks, but I don't know exactly how this would work, or where in Canada a DIYer could get his hands on a Nitrogen tank.

Sniffers are out of the question since they are a lot of money, and there is no refrigerant in the system to sniff.

I can also start replacing everything, but lets say I'd rather find the leak first, and replace only what is necessary instead.

I'm wondering if anyone dealt with a similar issue and could share their experiences with difficult to find leaks and an AC system in a not exactly working state.

Appreciate any input fellow enthusiasts.

xp

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1985 190E 2.3L - a constant project.