A/C leak

[The Warden]

Hello!

I replaced my a/c pressure switch today, only to find that it wasn't the problem. I've got an a/c leak somewhere in the truck, that was bad enough to drain the system to the point where it wouldn't cycle.

I found one fitting that was somewhat loose, and the pressure switch threads had stripped to the point where I couldn't unscrew it (I had to cut the plastic parts with a hacksaw blade to get it off).

I guess the big question is, would the somewhat-loose fitting (it was tighter than finger-tight, but I was able to get it tightened a good 1/4 to 1/2 turn) and the stripped-out threads on the pressure switch be enough to make the system go from full to won't-activate-the-switch in 6 months, or do I need to be looking hard for another leak? If the latter, does anyone by chance have any tricks on how I might be able to do it myself with limited tools, or do I get to submit and go to an a/c shop?

Thanks!

 

[hardknocks]

soap bubbles ?

 

[JPR]

The o-ring should seal if you got it just more than finger tight.

 

[The Warden]

The o-ring should seal if you got it just more than finger tight.

On the pressure switch?

The old one (with the striped threads) could actually turn by hand with some difficulty. Only thing was, I could spin it all day and it wouldn't back off any...

 

[JPR]

On the pressure switch?

On mine, fitting had an o-ring behind the threads.

 

[The Warden]

On mine, fitting had an o-ring behind the threads.

Right; so does mine...I was just making sure that that's what you were talking about, as opposed to the other fitting (which IIRC also has an O-ring on it).

I still don't know for sure if the stripped threads would have made it unseal slightly...that's sort of what I'm hoping for, though, since I don't see any other place (other than that one semi-loose fitting) where it'd be leaking from...

 

[Guntherx]

Fords are notorious leakers at the orings on the snap together seals that go into the evaporator. the leak is sow, so unless you have access to a leak detector even bubbles won't detect it. I have also had to replace the evaporator in my truck. Not a terribly hard job, but you need the equipment. you may be able to do the evap swap and have a shop pull a vacuum and chage it.

 

[The Warden]

Fords are notorious leakers at the orings on the snap together seals that go into the evaporator. the leak is sow, so unless you have access to a leak detector even bubbles won't detect it. I have also had to replace the evaporator in my truck. Not a terribly hard job, but you need the equipment. you may be able to do the evap swap and have a shop pull a vacuum and chage it.

"Snap together seals"? Is this just a term I'm unfamiliar with, or was something changed? I've got what seemed to be standard fittings on both sides of the evaporator...

BTW, I actually have the equipment to pull a vacuum on the a/c system, except that a fitting broke on the pump (see a thread I started in the Lounge), so I need to repair that before I go further. I just need a shop to evacuate the system first...

Fortunately, I may get to borrow a leak detector I'll keep the thread updated as things progress...

Thanks!

 

[Guntherx]

"Snap together seals"? Is this just a term I'm unfamiliar with, or was something changed? ...

The connectors at the evaporator just push together and are held in by a spring inside of the fitting. A special tool is needed to push the spring back and release the fitting. In reading in a MACS periodical, Ford denied problems with the fitting and seal , but it was a very commonly reported problem by techs .

When you check with the sniffer, be sure to go inside and shove the sensor into the heating duct at the floor board. if you get any thing there, it is the evaporator. While your at it, you may want to consider diong a 134A retrofit. Its easy and cheap and does a nice job.

 

[kwazyca]

I am talking out of my rear end here but........I thought I saw where you could detect AC leaks with A UV kit you buy at Kragen or Autozone. I saw cans with "UV added" for sale under the detection kits.

I just glanced at the kits but they looked pretty simple.

FWIW,

Tom

 

[The Warden]

The connectors at the evaporator just push together and are held in by a spring inside of the fitting. A special tool is needed to push the spring back and release the fitting. <snip> While your at it, you may want to consider diong a 134A retrofit. Its easy and cheap and does a nice job.

Okay, something changed...I completely disassembled and completely removed the air conditioning system on my truck last year while I was doing the head gaskets, in order to flush the system out and convert to R-134a (changed out all the O-rings, etc). I was able to disassemble and re-assemble the system only using wrenches...so it looks like the push-connectors at the evaporator were added in sometime between '84 and '88. (this makes sense; I also have metal/rubber fuel lines instead of the plastic lines seen on mid-'85 and later trucks)

Tom, thanks for the heads-up! I'll keep that in mind in case something happens and I don't get to borrow the leak detector...