New A/C Problem

Topped off Freon, took a ride, mid 80's humid out. Cool but not real cold like it should be in car. Duct temp mid/upper 50's.

Problem is in picture, gas bypass valve frosted hissing & leaking dye(nasty stuff!). Ever seen this? Major problem?

What's next?

Thanks

Paul, there is an 0-ring in there that I told you about . Now is your chance to get the undercoating off. Remove the unit, replace O-ring and it should be fine. If not, just find plugs for the connecting pipes...the a/c will work better than before since that would put it into max-a/c mode with no temperature control.

By the way that is a liquid bypass the diverts liquid refrigerant back to the compressor when the set temperature is satisfied...just a way to make it less efficient. I have all of mine disabled (removed the ground wire) since around here I need all the cooling I can get. I might have one if you need it...call if interested.

Willie

Thanks Willy, yea I remember now. So that means evacuate. Should I throw an oil charge in when I recharge or should there still be enough left in there?

Just looked at that picture, looks like something from "Alien", don't it? I thought a blown head gasket made nasty looking stuff!

Paul

Some more suggestions: If you cannot fix it right away, assume your drier is contaminated with moisture, but you can install another at the line junction in front of the right rear wheel...if you cannotget enough slack, you may need to cut and flare the line...install aftereverything else is installed and leak checked.

Sporlan C-053 3/8 flare ( not the C-053S which is asolder unit) is the one I use.

Another potential trouble spot is is the sight glass which has O-rings also...I have never been able to replace without breaking the glass so I use a Sporlan SA-13 3/8 flare.

I did find a liquid bypass solenoid that is working...I can refurbish for you...trade for some R-12??

Willie

I will get to this today. I was in the car in the driveway yesterday and saw a puff of smoke/vapor from the that area. So whatever happened was yesterday.

Lemme get it off and look at it,seems like an easy fix if I can find that O-ring.

Sight glass,so far so good.

What about the oil charge, think it will need it?

Paul,

There is a good chance Fastenal will have the O-ring.

Oil should be OK, unless you estimate more than 2 oz lost. The sight glass will soon fail!...that is the last weak point in the system and the replacement even has a moisture indicator. You have to draw the line somewhere on 'original' parts (don't be like the guy that tried to drive a late 40's Buick with the original fuel line just because it was 'original').

Wear gloves when dealing with that dye laced oil...otherwise you will look like you had been fingerprinted like me last year.

Willie

Don't know if the O-ring is completely disintegrated but I'm not seeing one here. Unless it is in the body, which is difficult to see how to disassemble because of all the dirt and undercoat.

Answered my own question. So much dirt didn't see the Allen keys. Got the body apart. O-ring is petrified,shows signs of leaking. Will look for one.

It is hard to tell from the picture, but if you have oil in the coil area, there are other problems that an O-ring will not fix. Anyhow replace the O-ring and leak test.

I thought that too but that is gloss paint it is actually dry.

Just one(or two) more things. Cleaned up the body and noticed it is a directional valve. Which way do the arrows point?

When the body came apart the little circular piece dropped out. I did not see which way it goes in. Metal side up towards cylinder?

Found an O-ring that may fit. Will try with a little sealant and see if it holds a vacuum.

Thanks

Paul

Just one(or two) more things. Cleaned up the body and noticed it is a directional valve. Which way do the arrows point?

When the body came apart the little circular piece dropped out. I did not see which way it goes in. Metal side up towards cylinder?

Found an O-ring that may fit. Will try with a little sealant and see if it holds a vacuum.

Thanks

Paul

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The arrow should be the direction of fluid flow and should point to the rear.

Metal side of disc toward electrical components; non metal side toward screen shown.

Never any sealant, just refrigerant oil; no teflon tape on threads of flare fitting...again, just refrigerant oil.

Willie

Once again Willy, I thank you.

Got to say that undercoating was a bear to remove but preserved the valve body pretty good. The undercoating probably failed and caused the leak!

The arrow should point from the narrow high-pressure line towards the thicker low-pressure line.

I had a leak there as well on my '54, between the two brass pieces held together with allen-head screws, and fixed it with a modern o-ring.

The rubber disk has the metal side up, and the rubber side down, towards the sealing surface and the brass screen. Just blow through the inlet side, feel where the air is coming, and you will understand. You need a rubber seal against the small center hole. That closes when electricity is applied and the system pressurizes for cooling.

Good luck!

Ok.The never ending saga.

Changed the O-ring,vacuumed and charged the system, no red on the paper towel under the bypass valve,so seems not to be leaking

However, duct temp high 50's, low sixties and compressor is cool and sweating. Like I am getting!

What's problem and cure this time?

Put a Friedrich in one of the windows?

Paul, It is possible the bypass solenoid was previously inoperative and is now working (hopefully you bench tested and demonstrated that it opens and closes). All of mine 'think' it is time to bypass refrigerant before I am cool enough...that's why I leave the ground wire disconnected, which will put it into max a/c and never bypass mode with the thermostat dial ineffective.

Another possibility is too much refrigerant or oil. With R-12 I charge until the liquid line just fills with no bubbles and no more.

Try it with the ground wire off the bypass and report back.

Willie

Bypass is disconnected. Engine off, if I tap the sight glass there are a couple of tiny bubbles. Air is system? Expansion valve problem?

Like I said compressor gets cool and sweaty, not frosted. Return is sweaty and cold,but not real cold.Duct temps around 60.

Today the compressor made a quick grunt when I engaged it. Very quick but noticeable. Seemed to work ok after that with the usual clackety clacking.

Should I just start from scratch with a new vacuum and charge?

Would be cheaper to buy that Freidrich!!

Is this the first time you mentioned the clackety-clack? Do you know where that noise if coming from?

Paul

Don't blow the refrigerant charge...I can show you how to capture 95%.

The sight glass should show all liquid with the engine running and a/c on. ( and if you replaced the sight glass the moisture indicator should show green)

Hook up your gauges and get us some pressure readings along with the approximate outside temperature and humidity at the time.

Also get the temperature of the liquid line(s) on the way to the back: line before the bypass and both lines after (behind) the bypass. This is with the bypass electrically disconnected and all tests at fast idle (~1200 rpm)

Then get the temperature of the return line just outside the evaporator and at the compressor.

I hope you are skinny and have a laser pointer on your heat gun .

...and don't tell us "I want to skip these steps and try something else."

Willie

Is this the first time you mentioned the clackety-clack? Do you know where that noise if coming from?

John, the A-5 compressor is noisy at idle...I hope that is all it is.

Never ending saga. The valve body(rear of compressor, high and low line with shut offs) is shot. Closed the high line to attach the gauge,took off cap and massive eruption of freon. Like no valve was there. Found an NOS unit on ebay. Gonna have to go for it I think.

Never ending saga. The valve body(rear of compressor, high and low line with shut offs) is shot. Closed the high line to attach the gauge,took off cap and massive eruption of freon. Like no valve was there. Found an NOS unit on ebay. Gonna have to go for it I think.

Yikes, getting frozen will hurt! Paul, is it leaking around the stem or the service port where the gauges are attached? Be sure the valves are turned counter-clockwise all the way, crack them clockwise only after gauges are attached...I replace the caps over the valves before turning the compressor on (all of mine leak around the stems when the pressure is raised).

Call for details if you want to try to recover at least some of the refrigerant.

Willie

I don't know that I'll be able to save much. It came out with such force it took a full 30 seconds to get the hose attached. The latex gloves I had on were pretty stiff. The sight glass had a few small bubbles before, now pretty big one.

Waiting to hear from person with NOS manifold. Seal on mine must have let loose, was a little leaky before,but now, fuggettaboutit!

On the bright side, the inner fender looks really nice after I cleaned up the mess.

Hope everyone's Fourth was a good one.

Back to business at hand.

Just to cover all the bases,I took the access cover off the evaporator. At the bottom of the expansion valve near cap nut was a tiny drop of red fluid(leak detector I assume).Took cap nut off,pretty clean and shiny. Tiny amount of red right around rim. I do mean a very small amount here,but did show on a white paper towel.

Big problem?

A/C info I have(maybe for 1954) says to adjust expansion valve, close and then back out 5 turns.

Same for 55? Don't mess with it ?

I will then get the the requested pressures and temps.

Paul, I have never messed with it, so if you try you are on your own and will be the resident expert.

Willie

I doubt your 55 valve is any different than mine. The '53-54 manual (pp. 22-23) calls for 7-12 turns, with a starting adjustment of 9. If you can't get proper pressures within those specs, it calls for replacement of the unit. I can see how the valve spring would get tired after 60 years, so perhaps a few more turns past 12 would not be a big deal. You need the correct AC manual for your car.

I have never taken an exp. valve apart nor tried to adjust it. Looking at the cut-away picture (p. 11), I do not see an o-ring that could be replaced, but it seems there should have to be one at the adjustment shaft. But I would not want to take it apart unless I have to.

Another possibility might be to find a soft copper washer to seal the cap at the adjustment end of the part. That might help hold back the leaks.

Can you live with a little leakage? Are we expecting modern sealing on a more primitive system that assumed a little leakage and some more regular servicing and re-charging? Freon was cheap in those days. My '96 Impala has only been serviced once in 120K miles. I know my '54 will never get that well-sealed, and doubt it ever was when brand-new. Can I get an Amen from Willie?

I did manage to buy what I believe to be a correct NOS replacement on Ebay last summer, here:

This is my fall-back in case the original fails me, I hope you understand... Keep an eye out on Ebay for Frigidiaire expansion valve.

That is part of the problem. I have never seen a 1955 specific A/C book. I look often. I have seen 53-54 Buick, Cadillac and 55 Olds books but not 55 Buick. Anyway those other books call for anywhere from 5 to 20 turns on valve. According to the Master Chassis book, the valve is the same 53-55 for all divisions,if I read it correctly.

By the way the valve can be turned using the 3/16" hole on the A/C valve ratchet wrench.