AC compressor gone. Tips on replacing/fushing myself

[elwood2]

I have a 91 Ranger. The person who had the truck before me changed the serpentine belt, bypassing the AC compressor because it locked up and was causing the belt to smoke.

This was years ago (6-8yrs) and i've been having the truck about two years and i've finally decided it is time for some AC!

I tried turning the the compressor by hand and it turned a little bit but was very rusty feeling. Since it moved a little, i assume the compressor is gone and not just the clutch.

I got two quotes, one from a shop that specializes in automotive AC for $350 in labor, and one from another shop that does mechanic work and AC on the side for $375. That with me supplying the parts on both (compressor, drier, orifice tube).

I do most of my own repairs and maintenance on my vehicle as long as it doesn't take an expensive tool that i cannot borrow or rent. I also have some experience in AC repair as i worked for a AC/appliance repair place for a few years. Auto AC's are essentially the same thing just on smaller scale.

So I'd rather save a few hundred bucks and do what i can myself. I'd like to do as much as i can myself without having to buy specialized tools (vacuum pump, manifold gauge, etc) that i will probably never use again.

First question: Just to make sure, are all of the new compressors being sold compatible with r-134a?

Ok, on to what i am looking to do..

The system is still charged with R-12. I am going to take it to a shop to evacuate all the old refrigerant. After that i am going to pull the drier/accumulator off, then the orifice tube, then the compressor. I am looking at buying a can or two of this to flush out the hoses and the condenser. My hoses look to be in excellent shape but i will change them if needed.

Here's how i plan on executing this:

1. Bring it to a shop and have the r-12 evacuated
2. Come home, let the truck cool a bit.
3. Remove old accumulator/drier
4. Remove old orifice tube
5. Remove old compressor
6. Remove all hoses
7. Flush all hoses and condenser (opposite direction of flow) with aforementioned aerosol flush.
8. After making sure everything is flushed out good, put the new parts back in and connect all hoses
9. Bring it to a shop and have it vacuumed, retrofitted, new serpentine belt put on, and charged up.

I'm pretty sure there are o-rings that i should change when putting things back together. Does o'reillys/autozone sell these? When putting the new drier/accumulator on, which type/viscosity and how much oil should i put in it?

Any other suggestions or recommendations? Thanks!

EDIT: I have access to a compressor to blow the components clean but it doesnt have a water separator/filter.

 

[elwood2]

Here's a tip for those out there who ever try to repair an AC system that has failed due to "black death":

Change EVERYTHING! Especially if it's been broken for a while. Don't spend an extra $200 having a shop trying to flush the condenser because it'll look like you got all the debris out but it adheres to the insides of the condenser, hoses, and other components.

My AC had been out when i got the truck so the system has been dormant for years. I bought a new compressor, drier, and orifice tube and brought it to a shop to have the parts changed, retrofitted, and recharged.

The guy spent the better amount of two days on it. He evacuated the system and flushed everything out. He said he was getting clean flush and a good flow the first time he flushed. He hooked all the components up and drew a vacuum for a while to assure no leaks then charged the system. He said it cooled perfectly for about a minute then it suddenly stopped cooling. He pulled the orifice tube out and it was totally clogged with sludge and trash.

He flushed the condenser once more till the the flush was clean and a good flow, charged it up again and ran it. He was getting very high pressures so he had to back the coolant down to about 50% of the R-12 charge (normally you put about 80%). This is most likely due to debris build up in the orifice tube and condenser.

I am going to change the drier (Again, just to be safe. only $20), all hoses, orifice tube, and condenser. Hopefully that fixes the problem.


Just a heads up to anyone running into a failed system with catastrophic failure known as "black death". It's cheaper just to replace everything.

Will post back after i change the rest of the parts and have it evacuated and charged again.

 

[ma96782]

Seems to me that you got a plan.

I'm pretty sure there are o-rings that i should change when putting things back together. Does o'reillys/autozone sell these? When putting the new drier/accumulator on, which type/viscosity and how much oil should i put in it?

O-rings are cheap and readily available. Get the "green ones." You could use AC oil to lube the o-rings or buy Nylog.

Since this is a conversion you'll have to make a guess at the oil and refrigerant capacity. Check at the top, NAPA has a guide to system capacities. Choose a closely compatable system to yours (except that it uses R134a).

Also, consider the orifice tube's color.........as your R-12 will probably be incorrect with R134a.

And, Yes.........put oil into the major parts before you take it down for a re-charge.

Aloha, Mark

PS...........I'd leave the accumulator for the last thing to do/change. Once it's on the vehicle..........I'd rush down to the shop. As, I wouldn't want to have my accumlator exposed to air any more than I had to. Even the air in the hoses has moisture.