OK. I've replaced the receiver/dryer and the suction hose (goes from the receiver/dryer to the thermonic expansion valve and then to the compressor), and put on new seals (both the metal one and this last time the O-ring.)

It STILL leaks at that side of the receiver/dryer, and it's hitting 97F outside right now!

HELP!

Does anyone know what order the seal and O-ring go on? Or even what I can do if it's still leaking there?

RwP

 

Ralph, I have looked everywhere that I can think of trying to find a picture. I replaced mine 4 years ago, but cannot remember how it went. That being said, I can see I did use a gasket on the receiver, but don't know about a o ring. Did you oil the gaskets before assembly?
In my FSM it does not show a picture or for that fact, not very specific. They say, (to reinstall, replace all O-rings and gaskets, coat all sealing surfaces with wax free refrigerant oil and reverse the preceding operation. )
Ill keep looking.

 

I've never worked on a system only filled the one. IDK if this sort of use would be prohibited as I never learned the refrigeration part of the trade. Nevertheless I make a habit of using petroleum jelly on all rubber or rubberised connections in any situation. I learned this pipefitting doing bell and spigot runs the lube made it go faster and helped avoid damage to the rubber gaskets as well as seal the joint. It works well on hoses and for O rings or any place you have a hard surface and a soft surface mating.

 

I don't think you want to use anything other then the refrigeration oil on the seals. Even slight contamination can cause problems.

 

What I used last time was Nylog (Blue), which is specified for auto A/C.

I did more digging - I wasn't supposed to use the O-rings, and it seems like others have also found problems with certain brands of receiver/dryers (same problem, won't seal worth crap.) Brand mentioned as working is Murray, and the local O'Reilly has at least one in stock in two stores in town, so tomorrow I'm laying out $20, buying a Murray and some more Ester oil, and tackling it again.

With it hitting 97F, I really REALLY want A/C in the truck this summer ...

RwP

 

Trying the Murray with the O-rings, a different size, down inside the R/D, not outside like I had put the others. Let's see if THIS one stays sealed under pressure ...

RwP

 

As a followup - I think I got THAT sealed.

When it hit 250PSI (note: 95F air temps!), it started outgassing out the discharge rubber hose ... the big one that goes to the compressor.

The surface started to pick up a touch of an oil sheen, you could see the water vapor on it, and ... the pressure started dropping. Razzle frazzle!!!

Of course, the hoses aren't in stock at RockAuto. LUCKILY Four Seizin's lists the stock numbers, so I can hunt them up elsewhere ...

As a side note, 500 miles in 97F temps without A/C is tolerable at 70MPH. Just.

RwP

 

That sounds like normal condensation on the outside of the hose. If it were "outgassing" as you say, it wouldn't be water vapor. Plus, it sounds like you're talking about the low side hose, not the high side, so it won't see that 250psi, anyway. Was the hose cold? If the A/C is working properly, the low side of the system should be cold, and the high side should be hot.

 

Well, we WERE at about 75% RH that day. The pressure kept going down after I turned the 30 lb canister off. And it was on the hot side hose - the one from the compressor to the evaporator.

Shooting it with a UV lamp later (my ester oil had dye in it), the sucker looks like it's got green measles ...

But shoot, it's a OEM hose, the truck is a 1988, it's probably not a barrier hose ... and it IS almost 28 years old! (Assembly date was September 1987 for my truck.)

Still ... leaks oil out the rubber, leaks R134a, won't hold pressure. I SWEAR I really ticked Murphy off in a previous life.

Sad part is, last summer I had cold A/C most of the year, until the clutch decided it didn't like being attached to the compressor and ... spun down, took out a fan belt, dented a couple of fan blades, and dinged the radiator where it blew out about three weeks later. I just have never gotten this "new" (from the boneyard) compressor, and the system, working since. Graurgh!! And it's supposed to be 102F this Saturday ...

I'm ordering new hoses (can't hurt!), and while I'm pulling the dash, I'll rebuild the HVAC box with a new blower motor, a new evaporator, and a new heater core. Again, see production date ...

RwP

 

Just for clarification, The refrigerant flow is as follows. Starting at the compressor, The high pressur hot gas comes out of the compressor, goes into the condenser, and is cooled to a high pressure liquid. From the condenser it flows to the metering device, flashes off from a high pressure liquid to a low pressure gas inside the evaporator. From the evaporator, it frows as a low pressure gas back to the compressor to start all over again.


FWIW, my 87 was leaking pretty badly when I got it. I found the bottom of the condenser rotted out. Replaced it, added a little mineral oil that I had. Recharged it with 134a. I too, have noticed my hoses are a little oily and I have to top it off once a year.
I know to do it properly, you should flush the system, change the metering device, and change the type of oil. If and when I loose the compressor, I will do all of that, but so far it works fine. And to be honest, I would not go to all the work to flush the system, and keep the old compressor anyways.
BTW when you are charging with 134a. are you liquid charging?