85 Nissan 720 A/C help

[lego126]

My truck came w/o an A/C, but with the summer fast approaching, and with my 2 yr. old. I thought I'd attempt to install one. I priced all the parts I'd need to get everything up and running and it'd have been well over a grand. And I don't need an A/C that badly, but luckily there is a pull-a-part (junkyard) a few miles down the road. So I get everything I need, get everything hooked up the
way it should have been from the factory. Turned it on, and began to fill up the system. After a min or so the compressor clutch kicked on. I was thinking all was good. Not cold as it should have been I think, but it was cool. I drove it to the gas station to get gas for the mower, left it running, windows up, A/c on max. As I'm checking out, I hear what sounded like a gun shot... :squint: And steam coming from MY TRUCK. I get outside and check it out, and the High Pressure line on the right side of the condenser running back to the back hook up on the compressor had busted right at the exhaust manifold, and that was causing the steam. But what would cause the busted line? Everything I used to put the AC in was from a junkyard, (pull-a-part), so none of it was new, including the lines.(maybe a lil' dryrot) When I got home I unhooked everything, and used compressed air and blew out everything individually, and there was no blockage or anything. Anyone have any Ideas? Thanks for the help

[hyperion]

When you put the system in, did you leak test the pipework and then evacuate the system? What refrigerant did you use when you "filled" it up? Possibly you had and air and refrigerant mixture in the system which would cause the lack of cooling and excessively high head pressure resulting in the burst hose. If you are not confident in checking it out, take it to a specialist.

[lego126]

Yes, I did vacuum it out, it held with steady pressure on it. I used 134A when I put the system in. I'm pretty sure after replacing the hose that the hose that burst was weak, dry rot. I've not had any problem since replacng the hose, but it's not cooling. Compressor is kicking on, , just no cool air.

[toshiro]

You should have changed dryer, especially becouse the sistem was ripped out from the junkyard and I suppose it was open, so the dyer must have reduced flow. Also check your condenser fan.

[mikeref]

Gee, where do i start..Were the parts you picked up in good condition and had the ends sealed?
Hoses are the first thing to crack and fail, so new hose lines are essential.
Is there sufficient air flow through the condenser when idling?
New drier and "o" rings throughout is a must.. Sounds like there is no high pressure safety to cut out compressor clutch.
As for the cooling side of things, lack of air flow across the evaporator from dust/ debris is a drama, and a poorly performing TX valve.. or orifice, ( whichever) will back up the refrigerant into the condenser.
Overcharging is a classic fault if you should work off suction pressure instead of the weight of refrigerant when charging.. Mike.

[lego126]

I put a new compressor in it, but not a dryer or xpansion valve. As far as air flow thru evap. I actually got lucky and the evap I got was in excellent shape. There isn't a condensor fan on this model. Only the fan infront of the radiator. Think I could have restricted air flow thru my radiator? I replaced all o-rings thru entire system. Thansk for the tips. I'll be getting a new dryer in the next few days and let you all know how it goes.

[aramis]

Can you measure your working pressures (high and low) with compressor running both idle and at high rpm (2500)? If your high-idle pressure is higher than 150psi don't do the high rpm test.

If you can't please take to an AC service, for your sake!