Air conditioner high pressure tube leak

Air conditioning season is not off to a good start this year. The high
pressure line that is routed under the battery developed a pinhole leak.
The tube showed signs of corrosion, probably caused by battery acid.
I attempted a repair by cutting out a few inches of metal tubing and
bridging across the gap with some of the high-pressure rubber hose
that's used for fuel injection. This was a good snug fit secured by
standard hose clamps. The fix worked for a couple of weeks until one end
of the hose blew off.
I reconnected the hose using a touch of Aviation Form-A-Gasket, but I
don't have any confidence in this repair. I expect another blow-out.
There is another '03 Forester in the junk yard at the moment, but its
high pressure line has a similar, though less-severe, corrosion problem.
The tubing is also available new from the dealer, but it looks to be
a major effort to replace while the engine is in the car.
Question: How would a pro fix this problem?
Reply to
Jack Myers
In non-mobile HVAC, a technician would cleanly cut the defective section out and braze in a replacement. Easy enough with experience but in this sort of AC the lines are traditionally copper. I guess that there must be some way of handling the task with steel automotive lines but I don't know what it is.
Failing high-side lines can be exciting. A long time ago I had a rubber line from the compressor on my Fiat 128 rupture while driving down the Las Vegas Strip; a huge white cloud, looking like smoke, belched from under the hood and the engine locked immediately from ingesting the Freon vapor and I thought I was really cooked. With a rubber hose it was a pretty simple fix.
Reply to
John McGaw
A pro would replace the a/c line. However, if it was for my own car and it involved removing the engine then I would cut out the bad section and install a short piece of the same material (aluminum?) using flare fittings.
Reply to
Paul in Houston TX
Either replace the line OR use a line repair kit. Those are really handy, they use a section of the correct tubing and two compression unions to replace the damaged line. There are also kits that replace metal lines with rubber to give you bending ability.
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examples. I have a big kit that Dorman used to sell. Really can get you out of a jam.
Many parts stores can get the individual pieces as well, Take the piece you cut out with you and match it up.
Reply to
Steve W.
It has been ages since I played with AC issues. But my recollection is that the high side pressure is in at least several hundreds of pounds per square inch, and sometimes up to a thousand. That's why the hose is not cut off and fixed with hose clamps at the ends as the car comes from the factory, but rather has special fittings that for most of us would have to come mounted on the hose. So that is why you buy a replacement hose rather than attempt to splice the old one... And that says the answer to your question is "the pro would get a replacement hose, with the fittings, from a reputable supplier."
To be honest I am amazed that it "worked for a couple of weeks"! This is coming from someone who has been improvising his way around what the books say to do for decades, that hose is not a good place to play. Bob Wilson, WA9D
Reply to
Bob Wilson
No kidding! I was in the drive-through line at In-n-Out when it blew. My mind immediately flashed back 50 years to a time when I was working on a factory floor and a compressed air line about 10 yards away let go.
Reply to
Jack Myers
Thanks for the pointers, Steve. Really appreciate it. The original pin- hole was located on a bend in the tubing. Stands to reason. High stress region.
Reply to
Jack Myers
Not just high stress but the tubing can have internal damage from the bending process. Being a bend is involved you could use a section of high pressure "rubber" line and have fittings attached at a place like NAPA or other places that do hydraulic hose work. Or hit a you-pull it yard for a replacement hose and use a section of that to repair yours.
Reply to
Steve W.
Federated just put this up about AC repair kits and pieces you can get at their stores.
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Reply to
Steve W.
Following up to my original post (quoted below) because others may run into this situation. The Subaru parts website is a bit misleading because it only shows the original factory-installed high pressure tube. The replacement comes as two pieces, namely: a front tube that runs back to the firewall, and a rear tube that runs across the firewall. It's simple matter to cut out the original tube and then route and connect the two tubes. Subaru parts guys see this all the time in the case of an engine swap where the front tube has to match the new engine the rear tube has to match the existing chassis.
A cheaper, viable repair alternative would be an A/C splice kit as suggested on r.a.t. Knowing the proper search terms I found a 5/16" kit that would probably work on the 8mm tubing, but I went with the factory parts.
Thanks for the helpful suggestions.
Reply to
Jack Myers
Not surprising they have an updated part. There are a lot of times a company will update a part but not the parts books/data. The dealer will look it up on their system and the new part number shows.
Reply to
Steve W.

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