1992 80 AC Repair... (1 Viewer)

[LS1FJ40]

So, I think I'm ready to delve in to repairing my AC on my 1992 80. My AC system is completely empty so I'm assuming I have a leak somewhere. I was going buy a leak detection kit to see where the leak would be but I'm also going to convert to R134 so I have a couple of questions:

1) Should I just replace all of the O rings and change the oil then fill with R134
2) Do I need to clean or change anything prior to doing this?
3) I cleaned my evaporator over the winter and she is spotless (relatively) now.

I've read so many threads on this that I feel more confused now than I did before I started. I really don't want to pay someone to do this (nor do I have the funds to) and I need to get my AC working properly so that my defrost works in the winter time. I really couldn't care less about the AC but the defrost is crappy now.

Anyone have any guidance? How about O rings part numbers or sizes. And anything else I will need. Thanks in advance.

 

[Landseer]

First you'll want to open up the system and flush out all of the mineral oil from the system, using something like this:
http://www.amazon.com/FJC-2710-System-Flush-Kit/dp/B0002JMEQW

Keep in mind that you cant flush through the compressor, dryer or expansion valve. After you've flushed the system replace the O rings, I got an O ring kit from Rock Auto that had at least 60 O rings in it that appeared to be very good quality. Before you bolt up the system you need to add PAG 46 oil, make sure to add some directly to the compressor, the FSM tells how much you need I don't remember off the top of my head. Its a good idea to get PAG oil with UV dye in it or add UV dye to the oil, this will make finding any future leaks much easier. You'll now bolt up the system with a new dryer and possibly new expansion valve (see below). Screw the R-134a adapters onto the R-12 Fittings.

With the system closed attach a vacuum pump and evacuate for roughly an hour. Turn the pump off and check the pressure, then let everything sit for at least 15 minutes, if the pressure rises significantly you have a leak. Assuming that you don't have a leak you can now begin to add R-134a.


Expansion Valve:
The expansion valve for R-134a systems is different from the valve for R-12 systems. The valves appear to have the same physical dimensions and should be interchangeable but likely have different properties regarding the flow of refrigerant. People successfully swap to 134a without swapping the expansion valves but if I were doing it I would get a 134a expansion valve. Also, Denso is OE for the expansion valve so no need to buy the part from Toyota.

Parts Needed:
R-134a adapter kit
Dryer
O ring kit
Flush kit
Expansion valve (not strictly necessary)
PAG 46 oil
R-134a

 

[Rifleman]

Landseer wrote: With the system closed attach a vacuum pump and evacuate for roughly an hour. Turn the pump off and check the pressure, then let everything sit for at least 15 minutes, if the pressure rises significantly you have a leak. The correct thing you are checking for is to see if you have a Vacuum lost on the manifold gauge, not a rise in pressure on the manifold gauge.

 

[LS1FJ40]

Thanks for the post. I totaled that up to about $250.00. I'm going to start accumulating the parts.

How difficult of a job is it? I'm a mechanic (maybe 2.5)...

 

[Landseer]

The correct thing you are checking for is to see if you have a Vacuum lost on the manifold gauge, not a rise in pressure on the manifold gauge.

Loss of vacuum is a rise in pressure.

Does the $250 include a vacuum pump and gauges?

 

[Landseer]

The most difficult part will probably be unbolting the compressor to drain the mineral oil, its really a pretty easy job.

 

[Cruzerman]

I just did the same job on my '93, converting to R134a from R12. I have a short thread here:

https://forum.ih8mud.com/threads/a-c-r12-to-r134a-conversion-success.877072/

I would definitely replace the expansion valve. It is only about $15, and since you have to go through the hassle of pulling out the evaporator, I would replace it as a matter of course. Pulling the evaporator was the hardest part, and that wasn't too bad. Good luck.

 

[LS1FJ40]

Loss of vacuum is a rise in pressure.

Does the $250 include a vacuum pump and gauges?

No it doesn't. I'm hoping I can borrow some from a buddy...

 

[LS1FJ40]

I just did the same job on my '93, converting to R134a from R12. I have a short thread here:

https://forum.ih8mud.com/threads/a-c-r12-to-r134a-conversion-success.877072/

I would definitely replace the expansion valve. It is only about $15, and since you have to go through the hassle of pulling out the evaporator, I would replace it as a matter of course. Pulling the evaporator was the hardest part, and that wasn't too bad. Good luck.

Why do I need to pull the evaporator?

 

[Landseer]

$250 is way high for the parts, I think you can get it all for about $120. You'll need to pull the evaporator to flush the mineral oil out of it (the expansion valve connects directly to it and you cant flush through the expansion valve).

 

[sbman]

It only takes about 20 minutes to pull the glove box and various wires to pull the evaporator cooling unit. It's not a bad job, having some long extensions and flex head metric sockets makes life a lot easier. The FSM has good instructions. I took the evaporator and condenser to an A/C shop and had them flush and pressure test them both for $45. I flushed all the lines with brake cleaner and compressed air (recommended by A/C shop). The A/C shop also ordered new Denso parts as requested at reasonable prices.

 

[Cruzerman]

I pulled the evaporator to clean out all the old oil. I was pretty determined to get this working and wanted to replace all the O-rings. Since it wasn't too hard, I figured I'd pull it out, replace the expansion valve and O-rings between the two, and give it a good cleaning with the solvent. Also allowed me to clean out all the fins. May not have been necessary, but I did it anyhow.

 

[Landseer]

Cruzerman, did you use an R-12 or R-134a expansion valve when you replaced yours?

 

[FZJ80 in KC]

Why do I need to pull the evaporator?

You'll see when you pull it.

That area is common for catching whatever debris blows through the box containing the evaporator. Mine had a nice little nest of gunk all over the coil that you'll want to clean off. We just did this job again on my buddy's rig, and this is what he found.

And while you're there, replace the expansion valve/block (it's such a cheap part, but can kill your AC rebuild if clogged...my system had been empty for at least 3 years, and I had little crystals clogging mine).

I bought an O-ring kit from Advance or O'reillys that had all the rings I needed for the system (replaced all of them at every connection as well).

The common parts stores also will carry the flush, in both liquid form and in a compressed can. Just squirt the compressed form into the lines, then use compressed air to push through and flush.

R12 to R134 retrofit kit is also at the common parts stores (O'reillys had them when the other stores were out)...about $7.50 I believe. Just make sure to remove the Schrader valves from your R12 ports before screwing on the R134 retrofit ports on top of them.

Oh, and I stuck with the correct expansion valve for my year (R12). Denso states that the expansion valve is sufficient for both types of refrigerant.

Blowing Ice cold!

*edit* just saw you already cleaned out your avaporator

 

[LS1FJ40]

Thanks. Yeah, it was disgusting when I pulled my evaporator this winter. Tons of build up of leaves and dirt. Just was wondering if this was the reason to pull it. Now that I know it isn't the only reason I'll get started on this this weekend. Hopefully.

 

[FZJ80 in KC]

Best of luck. Definitely a less than job, just takes a little time to run through everything. Oh, and when you replace the drier, keep the little rubber cap that comes with it so you can close it off when you flush the lines. Don't leave it attached when you flush (disconnect and plug the outlets). You don't want moisture in your drier.

 

[82much]

I just got my 1991 converted to R134 this past weekend. It cost me $200 and that came with a warranty from the auto shop.

Just my $.02

 

[LS1FJ40]

I just got my 1991 converted to R134 this past weekend. It cost me $200 and that came with a warranty from the auto shop.

Just my $.02

I've called around. $1000 is what I'm getting quoted.

 

[ihatecrashing]

Literally just charged mine and was so happy to get cold air! As with you, the more reading I did, the more confused I got. The most difficult thing was removing the AC compressor, I also had zero refrigerant and then found out I had practically zero oil in the compressor! Replaced all the o-rings with a cheap O'reilly's kit, new drier and expansion valve, flushed the lines, reassembled and pulled vacuum. Fired it up and started adding refrigerant and voila, cold air!

 

[82much]

I've called around. $1000 is what I'm getting quoted.

$1000!!!! is that for a complete A/C repair or just the conversion?