You can use the air con pump on your car to pull the system into a vacuum if the unit is fitted with (serves valves.)Shut off discharge valve disconnect ,discharge from compressor and run the aircon for a while, add a new gasket and reconnect while still running.There will be no pressure at the discharge at this time .There will be many opportunities to lose a finger or two if you don't pay attention to the job in hand.If you ignore a small leak and just fill up the system every year or two you run the risk of running the bearings in the compressor (if the leak is on the suction side ) this has the potential to bring moisture into system and will form an acid when mixed with refrigerant and the oil .The moisture will also stand a good chance of icing up the TX valve .Have fun and don't forget the 3 F's fingers ,fan,F....Hoppy ----- Original Message ----- From: "Kerry Pinkerton" <pinkertonk@xxxxxxxxx> To: <mailing-list@xxxxxxxxxxxxxxxx> Sent: Sunday, April 27, 2003 12:39 AM Subject: Re: IML: 68, R134 conversion > Harbor Freight sells a venturi style Vacuum pump for just a few bucks (less > than 20 I think). It requires an air compressor but will pull about 26 > inches of mercury. A good vacuum pump will pull 28. I got a Robinaire pump > from Ebay for about 120 bucks and love it. The HF thing will work though > and R134 is cheap if you have to have it redone. > > KerryP > Patch panels fabricated > Pinkertonk@xxxxxxxxx > dte.net/57imperial > Imperials -- 50 Limo, 57 roadster, 61's, 62, 68 Convert, 73, a 66 300 and a > bunch of lesser marques > ----- Original Message ----- > From: <chrysler1978@xxxxxxxxxxx> > To: <mailing-list@xxxxxxxxxxxxxxxx> > Sent: Friday, April 25, 2003 11:02 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 > > > >