AC Compressor replacement

[Green Mesa XJ]

Doing the compressor job on our 1991 XJ 4.0 auto 4x4.

I could see the old compressor leaking around the seals. I bought a factory compressor close out from ebay.

First thing I noticed is the new OEM compressor was harder to turn then the old one, but then the old one has over 200k on it. Is this normal?

As part of the job I replaced all of the lines, drier, and condenser, didn't want to do the evaporator unless I have to. Anyway the one of the things that concerned me here is the brass fitting on the liquid lines to the drier, I thought maybe these might be clogged or bad somehow. Any way I can check/know if these are working?

The reason I am going over all of this again is I am not getting cooling yet, although the wal-mart recharge kit's gauge died the first time it was used so I am not sure what the pressure is.

 

[Ecomike]

I assume (?) that you changed all the rubber hose lines????
If you are refering to the one brass check valve, I was told that it is factory installation tool, and is not a required part (which I and others verified by eliminating it years ago with no problem, but eliminating it requires an adapter, tube or similar. IIRC, I just ripped the check valve guts out of one of mine, and used it with no internals so the other parts would thread up, with needed any thing special.

From what you posted, it sounds like you overlooked replacing the expansion valve. I tried that on my 87 and 89 Renix jeeps, and they both gave me major grief, leaks, clogging....So that is probably your problem now. I got mine for about $25, aftermarket. They are the common clogging point!!! They have rubber o'rings inside and seat/seals that go bad, and any rubber hose or trash that gets past the dryer/filter clogs them up very easily!!!!

 

[Green Mesa XJ]

I assume (?) that you changed all the rubber hose lines????
If you are refering to the one brass check valve, I was told that it is factory installation tool, and is not a required part (which I and others verified by eliminating it years ago with no problem, but eliminating it requires an adapter, tube or similar. IIRC, I just ripped the check valve guts out of one of mine, and used it with no internals so the other parts would thread up, with needed any thing special.

From what you posted, it sounds like you overlooked replacing the expansion valve. I tried that on my 87 and 89 Renix jeeps, and they both gave me major grief, leaks, clogging....So that is probably your problem now. I got mine for about $25, aftermarket. They are the common clogging point!!! They have rubber o'rings inside and seat/seals that go bad, and any rubber hose or trash that gets past the dryer/filter clogs them up very easily!!!!

Thanks!
I did the expansion valve too, all the hoses and condenser are new (left the evaporator, didn't feel like pulling it and didn't look like it was leaking from the peek I had at it swapping the blower motor) .

I wish I had known about gutting the check valve. That is the one thing bothering me now, it's at the back of my mind just nagging.

Where I am at is enough pressure to engage the compressor and start things working, The hight side gets hot as it should but the low side is not getting cool yet. I probably need to add more freon but without a working gauge I'm a little worried it will go kaput if its over charged.

A buddy has access to a r134a gauge set, I'll try to get a accurate reading on the high and low side this week and see where I stand. I am worried the little brass fitting/valve is causing a problem. Are those small lines supposed going from the expansion valve to the dryer to feel hot or cold?

 

[Ecomike]

The small gets hot, the large line cold.

That valve is a one way check valve, so unless you see vacuum on the low side and too much pressure on the high side with gauges, it is not the problem. You really need to get a set of gauges on it now!!!

I have seen them on sale at HarborFreight for about $36 at times.

 

[Green Mesa XJ]

Yep that got it! Took it to a friend with a gauge set this afternoon and the high side was way too high, over 400. Discharged it, removed the check valves, reassemble put a vacuum on it, then recharged it and we are getting cold now. I'm going to check the levels again when we get a warm front though.

Those...Darn check valves were a little gummy looking, the one going in the fitting that attached to the hose was the problem, the way it was set in there it totally blocked the flow. ( the other check valve fitting attaches to the dryer)

Thanks for the advice Ecomoike!

Cheers!

 

[Ecomike]

Where was the first one?

My 85, 4 banger had one on the condenser and dryer, my 87 and 89, IIRC only had them on the dryer, by the time I got into them (IIRC, I may have just forgotetn).

 

[Green Mesa XJ]

Where was the first one?

My 85, 4 banger had one on the condenser and dryer, my 87 and 89, IIRC only had them on the dryer, by the time I got into them (IIRC, I may have just forgotetn).

They met around the Dryer on the 1991 4.0.
Expansion-Valve---Small-Hose--Valve---> <---Valve---Dryer---Small-Hose----Condenser.

I wish I had gutted them to begin with but I thought "hey they are supposed to be there for a reason", and I was pretty sure I wasn't going to find new valves easily. The valve connecting the hose looked jammed so it was not letting anything past it, the one on the dryer was fine I guess.

On the bright side I did see that the system held a good vacuum now so it ought to be in pretty good shape for years to come. Did miss the AC over the last few weeks, a few humid and warm to hot days were it would of been nice to get the windshield cleared.

 

[Ecomike]

I was told by and AC parts guy they had been obsolete and NLA for many years. He is the one that told me they were not needed, and to gut the insides.