Fixing a leak in the low pressure side A/C aluminum hard line (in a car)
 

This is kind of off topic for this forum since its in a car, but still relevant for general heat pump repair work.

The other day I was working on a friend's 2000 Saturn LS200 sedan. I fixed his evap problem, and he then mentioned the A/C wasn't working. So, we ran to the store, bought a can of R-134a and put it in. Still nothing. We drove it back to my house, popped the hood and I listened. I tracked down the slight hiss and found a leak in one of the low pressure side aluminum hard lines.

My question is, how can I go about repairing this? I know I can replace the whole line for about $80. But, is there a simpler solution? Can I patch it with some goop and a hose clamp or something like that? How much pressure does it need to hold up to? How cold/warm does the low pressure line get?

I am sure one of the in the know HVAC guys will jump in and let you know how this really should be done. But I have fixed one of these issues years ago with JB weld I scuffed up the line and applied two coats of JB weld letting I dry between coats.

I read about JB weld on another forum too. I think it would easily hold up to the pressure. I'm more worried about the heat cycling.

I take the line off and carry it to my local custom hydraulic hose shop. If it's not a complicated line, it comes out pretty inexpensive compared to pricing a new line.

I would also recommend JB Weld and have used it for many applications. It is cheap, quick and if it doesn't work, you still have to take out the line and replace it. I have found you need to scuff up the outside (I use ~200 sandpaper) and clean the area to remove any grease. Then the stuff really sticks.

I also like the idea of going to a custom shop and getting a line built if (when?) the JB Weld fails.

But you will be a hero if the JB Weld Works!!

Steve

Alright, I'll give it a shot. I'll take some pics and post them up. Thanks guys.

When you a/c is off the low pressure line is at underhood ambient pressure temps, 150F is about 265psi. Keep in mind the cost of recharging it if it leaks back out. $80 seems pretty cheap to do it once.

Thanks gtojohn. I agree, that is a better way to fix things. However, we're here to try new things and see what works. If JB weld holds, it would be great to know this for others trying to fix things up. So, I'll give it a try.

So, I watched a few youtube videos on vacuuming down and charging a car A/C system. There was also a suggestion to replace the receiver/dryer. My question is, if I'm vacuuming down the system, why would I need to replace that part?

Replacing the dryer would be more important if there had been a failure and you were more concerned with debris or moisture. The vacuum will remove the moisture. When you're done with your repair insulate the low side "cold pipes" with pipe insulation to reduce all the underhood heat gain increase your capacity. A lot of the new cars have insulation around the accumulator which is a great idea.

I have always wondered about the need to replace the drier if a material part has not self destructed causing shrapnel in the system. I always presumed you needed to replace the drier because it is possible to take water from liquid to solid through the simple use of vacuum. I've never investigated what desiccant is being used in an A/C system to attract and contain the moisture, and whether dropping a vacuum on a "moist" desiccant boils the moisture off, drying it out again. Interesting...