OK, folks... I'm working on my '71 coupe to swap out the old A/C compressor and converting to 134a refrigerant. I've disconnected all of the fittings, EXCEPT FOR ONE!! For the life of me, I cannot break loose the upper POA fitting (from the upper evaporator fitting to the top of the POA valve). The threaded fitting from the evap line is 1-1/16" hex and I can get my adjustable wrench on it and have made an extension torque bar out of some aluminum box tubing. The hex on the POA body (for holding it in place while torqueing the fittings) is 1-3/8" but is darned difficult to get at or position anything solidly on it.

What have you folks used to break that connection loose??? I've put PB Blaster on it for a couple of days, now. But, so far, no luck. Of course, that fitting has been in place for 46 years!!!

 

With all the great ideas folks have on this forum- post a picture and I'm guessing someone will have an idea.

 

You need a crows foot or cut down wrench, tough job for sure to get in there. Got to get creative and find the right combination of tools.

 

I've had good luck with Hoppe's #9 Gun Solvent, Better luck than with Kroil or PB in fact.
Can you get any heat on it? Steel fitting on an aluminum tube?

 

I feel your pain. I cut open a big box wrench trying to get that sumbitch to move, and, from what I recall, the lower nut isn't 1 3/8 but something like 1 5/16. It's been a long time but I do recall it was an oddball size. I had the one wrench working the top nut with another wrench holding the bottom nut which I could access only by removing the side grill.

Anyway, back to the story. After hours of work, I was getting nowhere and was starting to damage the evaporator nut. It was becoming very clear there was going to have to be a radical solution. I got a tube cutter and cut the evaporator tube exactly between the bends. After that, it took about two seconds to remove the POA from the fender. Happy times, no? But wait, there's more...! Once I had the POA on the ground where I could actually put some leverage on the wrenches, I put the wrenches to it and it took a near ungodly amount of force to break the nut loose. There was just no way on earth I was ever going to get it with the POA on the car. Yes, I tried various penetrating elixirs, heat, wax and everything I could think of.

So, now you have the evaporator with a cut tube. A new evaporator is about 200 bucks, which I investigated before cutting the tube to see what's the worst that would happen as well as the pain of having to pull the evap out of the car. So, when I got the rebuilt and R134a-adjusted POA valve back, what I did was go to O'Reilly's and get a 3/4" brass compression coupling to splice the tube back together. It was around 10 bucks as I recall. Yes, I know and everywhere I read said this would never work since the coupling would be riding on aluminum tube and it would never hold the pressure. And, for what it's worth, you can get a proper coupling for this and I did get one...for 40 bucks. The pipe sections are too short by about a half-inch each side for the proper coupling to work. I had nothing to lose by using the shorter brass compression couple and gave it a go. I put the nut ends on the tubes, slid on the compression sleeves and slid the tubes into the threaded block. Once I had everything ready to screw together, I put a healthy packing of red RTV (other colors may work just a well, so go with whatever color coordinates to your car) into the nuts and screwed everything together nice and tight.

I let the RTV sit overnight then pumped the system down. I let it sit until the next day. It absolutely held the vacuum for 24 hours. I put in some dye to find any leaks, charged up the system and got everything going to spec. I checked the system for any dye marker and it was completely clean. I checked for days afterward and it never showed any marker.

That was around four years ago and I ran the system a couple days ago and it still working perfectly.

So, will the brass compression coupler last forever? Maybe, maybe not, but the thing that for double-damn sure would not work at all seems to have worked for the past four years, and, remember, I had nothing to lose by trying it.

I hope this gives you an "out" once you give up on trying to get the valve out.

 

I know how you feel . Just went through this on my 69 ,a 1 1/4 wrench
Through the vents another one down from the top ,a crows foot works
Best . They do come lose easily. Good luck.

 

I'm going to be doing this in the spring. Do you have to replace the poa when converting to R134? Did you get one that is calibrated to 134?

 

You can send your POA in to be rebuilt or just recalibrated; or you can buy a gizmo that replaces your POA and it has fittings for the items you removed from the POA and for a pressure safety switch. I opted for the latter choice.
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gerry72...

I was really pleased to read your 'creative' reply...because the possibility of cutting that upper evaporator tube occurred to me, also. NOW, however, I have your testimony that this approach will actually work! Still not ready for that option, yet; but it is drawing nearer.

I was able to get another [larger] adjustable wrench on that 1-3/8" hex (yes, it really is that size; this is the hex in the center of the POA valve). It was wedged in place so the handle was locked against the backside of the right fender well. I put the smaller adjustable wrench on that top fitting, the extender bar on the upper wrench handle, and gave it everything I had. NO JOY!! It's either going to take a bigger 'gorilla' to crank on that torque bar or I'm gonna cut that damn tube!!!

 

I just bought a set of AC gauges yesterday to begin process of fixing my system....This doesn't sound like much fun.

Good luck...
Brian

 

I'm one of the lucky ones , I don't have air conditioning in my convertible . I just drop the top .

 

I'm just providing feedback to close this thread out....

After 3 days of using every conceivable method and tool at my disposal [and I borrowed several others], there was no way that upper POS---oops! sorry---POA valve fitting was going to loosen. So, I cut the upper {horizontal) run of 3/4" aluminum refrigerant line from the condenser {which ran to that fitting} dead in the middle.

I then hauled out that @$&/###^%$ POA valve with the connection still intact and immediately took it to my bench vise, locked down on that hex feature in the middle of the valve, and thought I could break it loose with my adjustable wrench. NO WAY!! I finally got it to break loose by locking the vise down firmly and putting a 2 foot extension bar on my adjustable wrench. And it came apart very unwillingly!!

While the valve itself was very clean (the engine compartment was detailed several years ago and I spray it clean on regular occasions), the threads in that steel fitting were well rusted and well-bonded to the aluminum body of that valve. There would have been no possible way for that fitting to be separated while still in the car!!!

I rounded-up an all-brass compression fitting for a 3/4" O.D. tube (usually used in an on-highway rig, I'm told) and prepared the cut tube for reassembly using that gizmo. [BTW, that fitting costs about $40 bucks ]. Went together fine and I have also installed the remainder of the 134a system conversion parts. I just have to take it to my favorite shop to have the system vacuumed down, checked for leaks, and charged with refrigerant. I'll let folks know how the system performs after that.

 

Thank you for following up....I'd be interested more info about that fitting just in case I have to go that way as well.

Brian

 

It's just an all-brass tubing compression fitting...but for 3/4" O.D. tube. I looked in Lowe's, but they only had them up to 1/2" size. The Parts City car parts place had it; and you can buy them on the internet.

I paid that kind of money for a quality part and because I did NOT want to remove the condenser system!

Good luck with yours...

 

very difficult in car, take the complete heater box out,
then it is easy to access with 2 large wrenches, to break that fitting free.
they almost weld in-place at this age.