72' F250 CS "Rex" Sold! -update

[fireguywtc]

All that black stuff around the expansion valve is a tar tape, commonly called "monkey poop" that wraps around the metal parts of the AC to prevent condensation from collecting in the cab.

[mcheath]

Ha! Monkey poop it was. So do I need to replace it? It had collected all sorts of gunk from 41 years, and was purty nasty.

The PO was who told me that the expansion valve was bad. Said the AC worked fine, then quit, he took it to our local AC shop and they told him it needed a valve and for the money they wanted he just gave up on it. Luckily for me the guy was all about benign neglect to the truck, instead of active harm.

[guhfluh]

Yes, it's best to replace it when you get the system running. Otherwise condensation will probably drip into the cab interior off the exposed tubing, etc. It doesn't have to be the same monkey poop stuff, just something that insulates.

The truck is looking great! You've come a long way with the stuff you've done!

[DCrusher]

Yes you can coil it up into a tight coil. Tye-rap it high and tight so nobody can kick it or sang it. The other question you had is how many pounds does it take to fill about 20 - 24 oz. or 2 can is a starter watch your pressures and temperature coming out of your inside vents. 40 - 50 degrees difference from outside to inside temperature is good R-134a doesn't cool as good in a R-12 system it works but not great especially setting and idling works better on the move so you can watch you temperature drop as you raise your RPM up. I hope this helps.

Here's where the valve goes under the dash.

valve out.jpg

And here's the new one installed. What to do with the long capillary tube? It's way too long, can I coil it up tightly? Once I put the heater back in there will be fit problems with it as it is now, I just have it up and looped a bit. I also wonder if it would break over time if it's not tightly coiled? Can it touch anything, or does it have to stay in open air so as not to mess up the feeler bulb's signal back to the valve?

Valve in.jpg

I've got some refrigerant coming this Friday. The clutch engages, and I tightened all the connections, which all seemed fine. Lubed the squirrel cage fans behind the evaporator, they were noisy but quieted down.

[LANCE65]

Trucks lookin good!

[mcheath]

Thanks for the all kind words.

We have AC!

It's only fair AC. At idle, outside temp 91 degrees, the air out of the vents was 60ish, give or take. At speed it was better, dropping into the mid 50's. So that's 30-35 degrees difference with the outside temp, not 40-50 like I'd hoped for.

Like I said, only fair.

To do the job right I should have changed the evaporator, and got better freon. (mine's used/reclaimed) And maybe a new compressor.

But I've only got about 75 dollars into this fix, the new expansion valve and the freon, so that's good. I can't justify spending the nearly a grand that I'm sure my local shop would want to fix the AC properly, so on the cheap it is.

A few pics.

One is the temp at one point coming out of the vents.

Temp at idle.jpg

Another is the manifold set when adding freon. I found this set on the side of the road in about 1983. One hose was ripped, so I replaced it, and have used it ever since.

filling.jpg

A final shot of the pressures. Low side is around 35psi, and the high is only about 160psi. Seems low. Any ideas?

Gauges.jpg

[guhfluh]

It is pretty low. Fan speed should be set to max when charging, but your pic shows low speed. That difference would bring the pressures up some, if you had it that way. It seems like its still low on freon or the compressor's bad looking at those pressures though.

[fireguywtc]

I agree it may be low on refrigerant or the compressor is too weak to bring the high side head pressure up where it needs to be. But you can add more to see what it does, shouldn't hurt it.

I also noticed it looks like the needle is bouncing on the pressures, that can be an indicator of a bad/failing compressor if the pressures are bouncing a lot.

[mcheath]

Yes the needle was bouncing around on the low side. (I had the fan at high when I charged it) The sight glass shows good as well. Looks like from what you guys are saying I may need to replace the compressor. Do any compressors from the later dentside Fords work? My local wreaking yard often has lots of these, but a bump with air is rare.

[guhfluh]

I believe they are the same style York compressors. Ford used the Yorks for a long time.

I don't normally go strictly by weight when charging a system either. I go by the gauges and if the system is happier with more refrigerant, I normally put it in. Newer systems dont have sight glasses to go by either though. I'd agree with fireguy with adding more and seeing how the system responds, if its easy and cheap for you to do, it should be much easier and cheaper than replacing the compressor, depending on what your refrigerant costs:)

[mcheath]

I'll try adding more freon, but I'll have to get some first. Yes that will be much cheaper than pulling the compressor and changing it.

Used the truck to haul my dad's old Honda the other day.

CAM00102.jpg

[Cipher43]

Love the Honda twin in the back. 74?

[mcheath]

Good eye, it's a 72'. It was dad's Shriner parade bike back in the 70's and 80's.

[Cipher43]

Ah ok. It must be a CB then because My CL450 has a different tank decal on it and they made the same design on those it seems for 72 and 73. Actually looking at it closer you do have the CB pipes on it.

[mcheath]

It is a CB. The tank Honda logo has been removed and replaced with a Shriner emblem, it reads "AAONMS", meaning "Ancient Arabic Order of the Noble Mystic Shrine".



Took Rex out for a spin yesterday to see what the AC would do on a typical summer day here.

Temperature: 99 degrees

Relative Humidity: 24 percent

Air blowing out of the center vent at speed was 68/69 degrees. At idle was 75/76 degrees.

The compressor seems to hardly load up the engine at all. I did find a small leak where I replaced the expansion valve, tightened it. Lost a little freon it seems, the pressures are a tad lower now. Rats. Should have checked for leaks better.