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Hi, 79 4x4 Longbed: Converting to R134a - System back together; R134a adapters, compatible oil in compressor, new receiver drier, new expansion valve,new pressure switch - while preparing for refrigerant, Vacumn indicates a leak - As I recall I only had to replace O-rings in the evaporator. AC install manuals for this beast are hard to find; I have a compressor manual for this model but I didnt touch compressor excepting re attaching Hi & Lo hoses and I saw no O-rings on those - (maybe one on receiver drier). Anyone know or know of a source I can confirm all the O-rings in the system? Thanks in advance.
I don't know of any source , but I do know there are orings on every hose connection , I'm in the process of doing it as well
Hi Slacker - Are you certain there are O rings on the hi & lo hoses from compressor to evaporator & receiver/drier? I never noted any...I noted only one(?) on the Receiver drier. Thanks,
Yes, there are o-rings that go in the compressor fittings. But why did you not replace the condenser? Unless it's relatively new with very few hours on it, I'd replace the condenser with new one. There's no since not to. All this work could be for nothing if it's clogged or half clogged.
I'd also recommend you replace the compressor clutch/stator and pulley. The bearings in that '79 are probably too old and rusted.
Hi Tims86 & Thanks - AC was perfect/powerful in Sep/Oct (2018) and crapped out after 6mos sitting idle as I was working on other parts - we blew out condenser while getting rid of old oil in all components - believe thats fine - there were no leaks noted prior to my reassembly - assume I missed some O-rings up front tho I still can't see how.
Well if you charge it up and see high head pressures on the high side you'll know why. I relate to saving some dough but don't like trying to flush condensers. Especially when they're as cheap as ours. Just go back and double check all your fittings and make sure you have O-rings installed. If you still have a leak a good suspect may be your high side hose (vapor line) going to your evaporator. Mine started leaking at the compression fitting. If I wouldn't have had dye in the oil I would have never found the leak.
One last thing, clean out your fan if you didn't already. And don't be an idiot like me and put it all back together again only to open the fresh air intake and dump another fan full of leaves into the fan again. Open your fresh air vent while you have the fan out.
Thanks very much for your insights Tims86 - enclosed two pics of fittings: where specifically would O-rings go on these? I saw none when I disassembled - Thanks,
Those lines are not the factory flare , that's a brake flare , a.c. flares are shaft with a seat , I'll get a pic , I'm not sure you would or could put a o ring on that line . I'll dbbl check on mine , maybe the compressed is like that , not sure .
Yeah, something is not adding up there. Like Slacker says those look to be the wrong style fittings. There's no place for an o-ring in a flare fitting, Who installed that?
Update: Hi all....removed & reattached all hoses/connections up front - system retains vacumn, added refrigerant however.....couldn't get the compressor to run (w/ 134a COLD air now) without jumping compressor power wire straight to battery...ugh...I must be too smart for this truck...(-*...So I looked underneath and noticed I'd failed (smart...) to connect the amplifier - but after connecting still no compressor start w/out jumping. so I'm gonna feel around/remove dash and ensure all connections are good and the AC switch on dash is functioning - can't believe new expansion valve and/or new ac pressure switch have failed. Trying to avoid draining evaporator etc....
11-05-2019, 10:51 AM
Open your fresh air vent while you have the fan out. 
