It has pressure a d the shaft moves. Sounds good so far.

Jot down the date and set a reminder to flush the brakes in a couple of years

 

100 psi is OK and that's of course dependent on ament air temperature which I would guess would have been about 90 deg that day.

The cycling switch set the hi and low cycling points. It does not stay at 50 or any other pressure. When the compressor pulls the low side down to 22.5 psi the switch opens up and the compressor stops. The pressure then rises in the low side as it starts to equalize and at (about) 46 psi the switch closes, compressor starts, low side goes lower, and the whole cycle repeats. How often this happens is dependent on RPM, air temperature, speed of car and blower motor fan speed and of course proper or improper charge of Freon.

 

Got her back together. Seems to work. Blows 46F air. Pressure while running is 33psi.

 

Update:
Used it the other day and when I got home I noticed an odd smell coming from under the hood. I opened the hood and discovered compressor oil had apparently spayed out of the what appears to be some sort of pressure relief valve on the top of the compressor. Not sure why but at this point i think i am going to have a pro check it out for me. I just hope if they have to replace the compressor they will use the new clutch. I checked the pressure when running and off at the low pressure port and found the value to be near 100 psi off and 35-40 running so there is still refrigerant in there but I have no idea how much oil at this point.

 

If your real lucky and the relief valve is bad you can have a pro evacuate the system and replace the valve (and add oil).

You need to check the high side pressure side to see what it is. If the accumulator or orifice clogged, the high side pressure might be in the 400s. But if it is normal in the 200 range, then the valve might have gone bad by itself and just needs replacement.

 

Thinking about just purchasing the equipment to evacuate the system myself so I can fix it. By the time I get done paying someone else to do the work I may as well get some tools for that money spent. Figure for about 800 bucks I can get a evacuation machine and tank. Going to get some gauges to check out the high side pressure.

On a side note does anyone know if 134a can be mixed with R12 oil? I have an old truck that ran out of R12 a long time ago. I figure most of the oil is likely still there I was wondering if I could just get some adapter fittings for the R12 connections and just fill it will 134a.

 

The answer to that question is NO. R12 requires mineral oil and R13a requires ester based or PAG oil. The two are non-compatible and do not mix.

I have an inexpensive solution to solve that dilemma (R12 - R134a discussion) that I will be happy to share only via PM as I do not wish your thread to become another one of those controversial internet puking matches. If you are interested, PM me and I will be happy to share.

 

And then what? It sits gathering dust? If you have the space and they are going to charge more, I suppose.

I wouldn't. Oil is NOT oil. It probably will do something bad.

 

Well..... the trouble I am having is I don't trust anyone to work on my cars unless I absolutely have to. I have been stung too many times over the years. You would think in Atlanta I could find someone that would/could work on these cars. Nobody is interested. I can't find a dealer that will work on it. There are so many people here most shops just don't want to hassle with an old car....why bother? they don't need to. I would have better luck in small town where shops rely on reputation and word-of-mouth to stay in business. I figure the labor cost alone would probably come close to covering the cost of the extractor and tank. I have 5 vehicles 3 of which are having AC issues. AC is such a specialty I am afraid if I bring it to a decent independent shop, they will just start replacing stuff. At least a dealer has access to the correct tools and system specs and part numbers to properly diagnose and repair the system. My guess is most of the parts for these cars are no longer provided OEM and the dealers just don't want to spend time tracking down after marker parts that may be of questionable quality. They make a percentage of their money by selling in-house OEM parts. They wont make much on aftermarket stuff and are not crazy about using parts that the owner may have sourced. Again.... it has a lot to do with this is Atlanta and they don't need the headache. Heck.... I cant even find a reputable engine builder around here for god sake! It is crazy.

 

Harbor freight has a vac pump for around $100. You may be able to rent one from Auto Zone. Either way, not too bad. Ive converted many cars to134A, no problem. Just buy a kit that has the 134 and oil and do it.

 

I have a vacuum pump, I just need to change the fitting. That is half of the battle. Other than the 134a fittings, I have no idea what the fittings I will need to connect to the vacuum pump or what is required to convert my R12 fittings so I can use with my r134a hose connections.

 

I've had bad luck and even worse luck with small town shops. I won't even patronize them anymore.

See if you can rent the vacuum pump from Autozone.

First off, go get a few quotes before you jump to conclusions. As to replacing parts, here is the issue. If you want to do bare bones, I'm sure they can if you don't expect it to last. Problem is people want to just charge and replace 2 parts and expect it to last.

They make money with any part. If they buy it from Autozone for $10, they will mark it up a few bucks. Same as getting it from GM.

 

I would say you need the newer hoses that are barrier hoses for the R134A. Dump out the oil at least and flush the lines. You MAY be able to get away with a "quick and dirty" but maybe not. On my system, I would not chance it.

 

I think maybe my issue has gotten a little lost here. The real issue is my 96 vette which is 134a. I am thinking about buying the equipment to just do it all myself. I mentioned my truck which is r12 and the truck may be worth 800 bucks. It is 30 years old and has 2300000 miles on her. Was looking for something cheap to possibly get it working at least for 1 more summer. I may have an answer to that and I am going to give it a try. The issue is my 1992 ZR1 which is throwing a low refrigerant code. I have 2 cans of r12 that I will use to top it off. I will need to buy a set of gauges and r12 to 134a adaptors. I also think a GM dealer probably gets a discount on GM parts and has to pay full retail on aftermarket stuff just like you and me.

 

Have you lost pressure?

 

the clutch on my 96 compressor cooked. So I replaced just the clutch. Then soon after on a very hot day oil and refrigerant sprayed out of the compressor pressure relief valve. I purchased a low pressure gauge and checked the low pressure reading at idle and it measure in about 35 to 40 psi I believe. This info is all earlier in the post. The pressure at rest with the engine off was about 90 psi I believe. I need a a gauge set to also measure the high pressure side to see what is going on there. The oil made a big mess under the hood.

 

Why? Does it sound like a problem that might be either caused by the clutch or was what caused the clutch to cook? It should not spray out if something is not wrong. I'd either make do without AC or spring for a total change. Anything else may be throwing good money after bad

 

not sure why the clutch failed. I suspect it may be related to either a bad compressor or blockage causing the hi pressure side to spike and being 25 years old. I just need to get a set of gauges on it and see what the high side is doing. I recall a while back I attempted to add some 134a for some reason. I think it was not blowing very cold. I may have over charged it. If I do decide to bring it to a pro, I want to be as well informed as possible regarding was the system is doing to reduce the chances of getting screwed.

 

what would be helpful if a couple of folks could put at a socket wench on the center bolt of the compressor with the car off and see how hard it is to turn by hand. I used a 1/4” ratchet with an extension. I forget what the socket size was. I could turn it fairly easily but there is no way I could turn it with just my fingers.

 

If that's my car, I'd replace all the hoses, flush out the cores and get a new compressor kit. Put the dryer in last, send it to a shop for charging