Rebuilding My A/C System

[RWrightPhotog]

Ok, here's how it is.

My Wagoneer came without an a/c compressor clutch or pulley and a very messed up under dash unit. Upon recieving the Wagoneer I pulled out the a/c unit, with the intent to not put another one in. That was in the Spring. It's Summer now and I'm'a singin' a different tune.

So I bought a new to me under dash unit and a new clutch/pulley from jsinajeep (thanks again!). I have it sitting in my room right now and it will start to go in tomorrow. My compressor was converted to 134a before I got it. I also have a new drier order from the local parts house.

So my first questions are...

There's a red and blue wire coming out of the under dash unit. The red I am assuming is power. Does the blue run to the a/c clutch, and if so is there a low pressure switch? I don't see one.

My second question is, I know that the thicker of the two hoses runs to the compressor, but the smaller hose, that runs to the drier, correct? It seems too short on the under dash unit I have. Now, that being said I have not test fitted anything yet.

After I get everything hooked up, I am hoping to take it up to my buddy Jimmy and Columbus Custom Exhaust and get him to put a vacuum on the system and charge it - and give me the good (or bad) news.

Did I skip anything? I will take pictures of my progress and might have a couple more questions come tomorrow. Hopefully it goes smooth and I will have cool a/c though.

I also should mention that I am running new wiring for all of this. I already have an auxiliary fuse box installed in my Wagon, so I'll be going fresh off of that.

Thanks in advance! Progress tomorrow!

[RWrightPhotog]

Got the under dash unit installed - what a pain! Also got the clutch put on.







Someone was obviously under here before! I guess they had never worked under the dash of a 300zx before. Compared to that I have tons of space under here!! I thought this was too funny!






Ok - now I need help with these wires... the red wire, I am assuming, has power off the fuse box running to it? And the blue wire runs to the clutch on the compressor?? Can anyone confirm that? I just don't want to fry my "new" set up! All of the original a/c wiring is toast, so I'm running new. Also, as I said in my original post, I do NOT see a low pressure switch anywhere. So, I'm assuming blue wire DIRECTLY to a/c clutch...



The other problem I have... the line that runs from the under dash unit to the drier is about three feet too short. The old line that ran from the old under dash unit to the drier is still hooked up to the drier and looks like it'd reach all the way, but I really don't want to have to open up the new under dash unit, so I am hoping my guy at Columbus Custom Exhaust can lengthen the line or something.

[COLOFIREMAN]

I was under the impression that a York style compressor couldn't be ran on 134A. Could be wrong but the info I had said they will lock up after a bit.

[RWrightPhotog]

I'm not sure, I have read a couple of posts searching where people have done it, but I don't know how long it'll hold up.

Right now my problem is that hose that's too short. I guess I will reuse the hose off of my under dash unit, but I don't want to break anything on the new one trying to switch it out, y'know. Also the parts house sold me the wrong drier. I ordered it on the phone yesterday, and was very disappointed when I picked it up today...

Oh, well, I'm about to take the new under dash unit apart and try to switch out that hose.

[Bob Barry]

I was under the impression that a York style compressor couldn't be ran on 134A. Could be wrong but the info I had said they will lock up after a bit.

The compressor in my '88 never had any problems; I ran R-134a for a half-dozen years, I'd have to guess. And it was the earlier-style York compressor, not the Sanden they switched to midway through the year.

[FSJ Guy]

I was under the impression that a York style compressor couldn't be ran on 134A. Could be wrong but the info I had said they will lock up after a bit.

I've never had a problem with my York on 134A. Not as cold as R12, but it works.

[jsinajeep]

The low pressure switch goes in the hose you have in your hand. I have been through my manual [77 81 84] and they all show the compressor wire to the fuse box aand nothing else going to the A/C unit under dash. I will try to get a picture of the hose and switch tomorrow. I would think the blue wire goes to the low pressure switch and the other side of switch goes to the compressor.

[jsinajeep]

Here is a picture of the low pressure switch and the hose to the filter up front.
I have a close up pic of the switch if you need to see it.

[Billygoat]

I was under the impression that a York style compressor couldn't be ran on 134A. Could be wrong but the info I had said they will lock up after a bit.

You need to drain the gearbox and run a PGA (ester) oil in it, but other than that they are fine on R134A

yes the red wire is key hot, the blue wire goes to the A/C port on the fuse panel, which is nothing more than a thru firewall port to the blue wire on the other side, it then goes to 1 side of the low pressure switch and the other side goes to the compressor clutch.
(you need to bypass the low pressure switch to fill the system of the clutch will not enguage) and you want the switch so if you run low on coolant you don't burn up the pump - less of an issue with a york since they have an oil sump, but they tend to loose all that oil along with the coolant.

note, the blue wire is only hot when the tempeture selector is cool enough to activate AND the fan is running

[TexasJ10]

If that system has been open to the air for a while, it may be hard to get it to work right. A lot of corrosion and other crud is likely to be inside and will quickly plug the expansion valave. Make sure you take the expansion valve off and flush the crap out of the evaporator, condensor, and all hoses with an a/c flush. You will probably need to get a new high side hose made for the one you only have half of. After you have everything back together you will need to pull a vacuum for at least an hour to try to get the moisture back out of the system.