Any AC repair shop will have a vacuum pump and a leak detector. (I have this equipment from the days when I ran a shop). You can make a vacuum pump from an old compressor, as I described to D-squared, but a leak detector is another story. You will have to beg, borrow or steal one, or take it to an AC shop and ask them to test the system for you. It is possible that an auto parts store may have one to loan - as the AutoZone chain does in this area. Very small leaks are almost impossible to find. When R12 was cheap and plentiful, if the leak was no worse than one 14 oz can every couple of years, we just ignored the leak and topped up the system when needed. With R134, we're back in the same situation again, so if your leak is no worse than the above, I'd just ignore it. If it is worse, you should be able to track it down with a good leak detector (mine is from Snap-On, but there are other good brands). These cost about $600, so this is not a cheap thing to contemplate buying. Dick Benjamin ----- Original Message ----- From: <chrysler1978@xxxxxxxxxxx> To: <mailing-list@xxxxxxxxxxxxxxxx> Sent: Friday, April 25, 2003 9:02 PM Subject: Re: IML: 68, R134 conversion > How do you go about "vacuuming the system"? How do you pressurize it to > test for leaks? How do you detect a small leak? > > ----- Original Message ----- > From: "Dick Benjamin" <dickb@xxxxxxxxx> > To: <mailing-list@xxxxxxxxxxxxxxxx> > Sent: Friday, April 25, 2003 10:17 PM > Subject: Re: IML: 68, R134 conversion > > > I converted my 55 Hudson about 3 years ago, and my 56 Packard about 2 years > ago - both are still cooling well. > > My son converted his 94 Jeep about 3 years ago also, and it is still working > well. > > In all of these conversions, I first vacuumed the system and checked for > leaks - and fixed the ones I found. I did not replace the original hoses > (they were not leaking). I had a bad evaporator valve (leaker) in the > Hudson, my son had dumped the R-12 by mistake as he was pulling his engine > for a rebuild, and the Packard has apparently a very slow leak (like 3 or 4 > years to go down) which I have been unable to find. The 134 doesn't seem > to make it any worse. I drove the Packard today, and ran the AC, as it was > a very warm day, and it's still cooling fine. > > Dick Benjamin > >