Automotive Air Conditioning Information Forum

Mine doesn't have a check valve, but it sounds like sometimes they don't work anyway. Then some have a thermal switch that might cut out while you're having lunch, and other things can happen. I won't walk away from the thing this time.

Here are some interesting cases I found while searching:
http://www.autoacforum.com/messageview. ... adid=28811
http://acsource.net/acforum/viewtopic.php?f=1&t=8237
http://hvac-talk.com/vbb/showthread.php ... nto-system
http://www.refrigeration-engineer.com/f ... 13148.html

Well, it looks like I'll be making new hoses instead. I can't shift this oil and the only thing that comes close, after a few tries, is acetone, which is no good for neoprene. I don't know what this vacuum pump oil is made of, but it's pretty unusual. I might keep experimenting but there's no point mucking up a hose if it eventually mucks up the whole system.

Have you tried brake cleaner? Are you talking about your manifold hoses?

Alcohol is a lousy solvent for petroleum products.

You can use Toluene or Xylene - the vac pump oil is just thick mineral oil

The hoses are nylon lined unless this is a 30+ year old R12 system.

You can use paint thinner, but then you need to get that out...

Well, Galaxy hose is neoprene on the inside, and after lots of experimentation today only naphtha will dissolve this vacuum pump oil. This surprised me since any other mineral oil I've dealt with will dissolve with water-based degreaser. So as neoprene and naphtha aren't recommended to play together I'll make some new hoses, which is okay since only a little bit was affected. And yes, there would still be the question of getting the solvent out afterwards, anyway. It's a brand-new system, so why risk it to save some money and time.

As for the gauges, I could run some naphtha through but I'll probably get a new set instead of risking contamination. At least they were cheap!