Getting the RV ready to go for the summer, and no a/c. I started to add freon, and found the leak right away.

It's on the 3/4" pipe that goes right over the upper radiator hose; obviously rubbing metal to metal caused the pinhole. Now I know where that mystery green snot came from all over my radiator hose coming back from Yellowstone last fall.

First thought was to replace the entire pipe. There's an easy threaded connector on the upper end, but way down on the compressor is a strange fitting that looks like a triangle stuck against a cube. I can't see how I'd get a wrench in there very easy anyway. What is that fitting?

I bought a Dorman 3/4" repair kit, but until it arrives in the mail I don't know if I've got enough straight pipe to work with. Anyone had any luck with these kits? Do I need to add oil as well as freon once I charge the system again?

 

If your not changing out the compressor you should still have enough oil in the system. You will need to vacum the system down for an hour or so before recharging. Make sure that the system will hold the vacum without the pump running to verify no other leaks.

 

I guess you are talking about the heater hose and not radiator hose. A/c line and radiator hose are not even within a foot of each other. IIRC
Never used one of those splices but looks like a regular compression tubeing splice with a extra soft sleve or collar to help seal the gas.

 

Yeah, might not be the radiator hose. This is an E-450, mind you, so things are pretty cramped under the hood. There is a foil heat wrap over the big pipe that the a/c line was rubbing on.

I read about somebody using some 3/4" ID hose and some hose clamps to fix a pinhole. You still have to cut the pipe to get the hose on, but at least you don't need that much straight pipe.

 

That sounds more like a CAC tube it was rubbing againt. Not really important tho.
Not real familiar with e-series. IIRC the 3/4 tubeing fitting is less than 3 in. long overall.

 

One thing to add to that. Hold the vacuum for at least one Hr after the
gauge shows it holding. The reason is after you get the leak fixed water
in the system will boil off in a vacuum and bring you back to 0 over time.
If you can let it sit under vacuum as long as you can. I had a system that
got water in it sit on a vacuum pump for almost 24 Hrs to dry it out. But
that was not an automotive system. Still dry is better and in this case the
more you can get out the better. That is less work the filter dryer has to do.
Be sure to check you vacuum pump oil and change it if it is looking like milk.
Water in it will do that and that is not good for you vacuum pump.

Now as to the fittings can you post some photos? Maybe someone
will know what the right answer is for you case.

Once you get things fixed have a good fun and safe trip.

Sean

 

When I would do my own systems I would hold the vacum overnight as a rule. I have posted that in the past and got a lot of flack about how unnecesary that was and such a waste of time. To each his own. I've never had to go back in for moisture in the system. If you do have to go back in that will also mean another new dryer. Do it once the right way and that is also the cheapest way in the long run.

 

Thanks for all the feedback - good stuff! I've got a small vacuum pump on order that runs off my air compressor. I've got a bid in on a 3 cfm electric vacuum pump / dual gauge setup on Ebay that looks like new too.

I temporaried a patch using harbor freight's extreme tape and a couple of hose clamps and put about 1/2 can of freon in to see if there were any more leaks. I think the patch held, but I don't see it holding up permanently.

I'm going to have to drive with the windows down for the weekend trip. I tried to explain to the wife that I have 2 a/c units on the RV. One on the roof that runs off the generator and the one on the engine, but I lost her right away.

 

Seems silly that they would give you any flack for making it so a job
would have to only be done once. Maybe they like spending money on parts
and the extra time away from the wife or girlfriend. Hmm now there is a
thought. Time away. Not me. I agree with you I only want to do a job once.


Sean

 

To the OP if you can use the compression fitting repair kit that will work but is not ideal. It will add 4 more places to possible leak. If you can get the hose/tube off and know someone that can weld aluminum, that would be a cheap permanent fix.

Harbor freight has a nice vacuum pump for about 170.00. It is electric, which IN MHO is the only way to go on a/c HVAC systems. I have used it on cars and home HVAC systems and have had 0 issues.

As stated pull the system down and close the valves off on the manifold set. Let it sit for at least an hour after documenting gauge readings. If it moves more then 2-5% you have a leak. Find and fix the leak if it is present. If no leak, open valves up and pull a vacuum for as long as you can. You will be glad you did.

 

Agree on the additional potential leak points, although I would think only 2 more. Maybe even one more, given the existing leak counts against the new fitting.

After the weekend trip, it is apparent we're going nowhere without A/C again. 104F in the cab, 90F outside; it was miserable. I got sniped at the last minute on the electric vacuum pump, so I'll be using the air powered pump.

 

I was gonna say try e-bay but I just looked and what they have listed is almost retail prices around here even at Auto Zone.

 

I have used regular old brass flare fittings on an AC system in the past with no ill effects.

when I did my Durango cummins swap, I managed to use the entire stock AC system and piping, aside from I needed a 90* bend in one line. so I cut the aluminum and flared it.
Not saying that it was the best LONG TERM option, but it worked fine for 3 seasons....

most residential AC uses Flared fittings, they can handle way more PSI than an AC system.

IMO, fix the leak, buy a new drier and get the system Pulled down and charged by a shop.
those venturi type dohickies will not get the moisture out.

 

You need to pull it into the TOR range of vacuum not "" of HG".


Sean

 

As I recall 18"hg will suffice.