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92landyacht · 08-04-2015, 10:09 AM

New receiver/drier is on the way and a huge package of O-rings that are R134/R12 compatible. Should have all the parts needed to start on her by Thursday. The only part that I haven't been able to source out is the Expansion valve. Hoping that it's still in good shape.

Found an adaptor right at the R/D outlet. I think it's a quick connect valve but not sure. Inside is a plunger/spring assembly that looks like a check valve. Anyone have an idea as to what it is? If it was a quick connect valve, then I think I can just gut it install it without the insides.

Keyair · 08-05-2015, 12:51 PM

All good solid advice!

I have worked on my own and my son's vehicles over the last 15 years, and virtually all of them are or were R12 systems. We did out AC license too!

My son has actually back converted his 1987 Mercedes 300TE from 134a to R12, and used the later E320 larger condenser/twin fans to boost his AC system for use in Az... He says it works far better than the original and the 134a conversion now.

My 0.02c...

1/ If you are looking for info on your basic system, look no further than the relevant model years of GM C or K trucks.

2/ All the system I have done so far, the issue was the 99.9% the original O rings leaking... of course, that meant a new dryer, and maybe orifice valve for surety.

4/ I have always started with pulling a Vacuum on the empty system... its free, and sometimes tells you a lot for nothing! Hear the leak... awesome... after that, I have also used my compressor to pressurize to find other leaks with a length of tubing to my ear.

5/ Replace EVERY O ring in the system joints... with HNBR units. I bought a Metric and Imperial kits and it has covered EVERTHING in my garage!
Cheap too.. Example.
http://www.amazon.com/Performance-To.../dp/B0002KO1XK

6/ Once the new components and rings are installed pull the max vacuum you can do with your pump and see if it holds for 24hrs...

Here is a couple of pics of the revamp I did on my now sold 1991 Mercedes 190E...
Compressor reseal with HNBR green rings visible...

After recharging with R12, it would output 35f air at 2000rpm with ambient air at 90f!

For years later, the new owner says its still ice cold!

I was lucky to find this on Craigs List for $200, so now, I am completely setup!

92landyacht · 08-06-2015, 11:59 AM

Well, it looks like I found the primary source of my AC problems. While I was in the process of changing out all the O-rings I could get to, I found that my expansion valve inlet was completely clogged with desiccant from a ruptured receiver/drier. The line leading to the expansion valve must have gotten real hot since the piping going into the expansion valve had actually melted and caused the loss of Freon. I was able to clear the debris from the expansion valve inlet using brake cleaner. There was an inlet filter screen on that side of the valve. The other side seemed to be clean with no signs of debris. I may replace it anyway. That's assuming that I can find a replacement unit that matches. Not easy since I don't have any part numbers or what they came off of. Removing the expansion valve was actually pretty easy since all the components were under the hood and not under the dash. Here are some pictures:

Expansion valve after I cleared the inlet screen:

Melted hose end that went into the expansion valve:

Now I need to find a replacement hose or have the fitting replaced:

Where the pressure switch connects to:

That brass fitting on the end of the hose is the quick connect/check valve.

If anyone knows where I can find these parts or what they came off of, it would be greatly appreciated.

bkahler · 08-06-2015, 12:18 PM

This is the Expansion valve I bought for my Argosy. I've never seen an expansion valve with an electrical connector like the one shown in your picture so this one may not work.

You can also look here for more expansion valves.

Brad

92landyacht · 08-06-2015, 01:27 PM

No electrical connection on mine either. The thing that looks like an electrical wire is actually a temperature sensor and the other is a pressure sensor. Both control the diaphragm. I think I was able to locate a match for the expansion valve on ebay:
Universal motorhome RV A C Expansion Valve with Female Oring Fitting | eBay

Now I only need to get the damaged hose repaired or replaced.

Keyair · 08-06-2015, 02:32 PM

Great pics and info Guys!

Keyair · 08-06-2015, 02:34 PM

Look at these peeps.
Cold Hose - AC Hoses, Hose Kits and Fittings

92landyacht · 08-09-2015, 10:13 AM

Had a local CARQUEST auto parts store make up the new replacement hose. They reused one of the custom fittings that had the switch port in it. The rest of the hose is all new and only cost me $36 for them to make it up.

Now I'm just waiting on the expansion valve to arrive in order to button up the system. Fist thing after that is to vacuum it down and verify there are no leaks. If all goes well I'll be charging the system soon after that.

One question though... I know I've lost some of the oil charge when I disconnected the receiver dryer and found there was still some pressure in the system. I've purchased a 4oz bottle of R12 Freon with oil charge and was planning on just putting that in first after I vacuum the system down. Figure I'll loose some more of the oil charge during that process as well. Any ideas on this?

The high and low ports are directly on the back side of the compressor. I'm assuming that I need to only add vaporized Freon/oil charge to that port. I don't want to risk hydro locking the compressor with fluid. I could also add the oil charge at the switch port between the receiver/drier and the expansion valve since that switch port is a standard R12 high side port and is accessible from the front grill area. That area normally has fluid in it if I understand the system correctly. My plan is to add the oil charge without the compressor running as the first thing and then add the rest of the Freon as vapor on the low pressure suction port on the compressor.

92landyacht · 08-27-2015, 07:14 AM

VICTORY!!! Finally got a chance to pull a vacuum on it and fill the system. Pressures now sitting at 30psi low side and 205 on the high side. Front electric fan came on as expected. Put in two 14oz cans of Freon 12 with dye, one partial can without dye and one can of oil charge. She's blowing cold air out the dash for the first time since I've own her. Very sweet to have dash air again. Total cost for the repair was $185. Replaced the Expansion valve, receiver/drier and one hose.