A/C System vacuums

[Cougar281]

I just picked up a pneumatic A/C system vacuum from harbor freght (part 96677) to draw down the new system in my car. How does a pneumatic vacuum compare to an electric vaccum? Better, worse or same? It seems to work; pulled vacuum pretty quick, now I'm just letting it run (Ford says have it on vacuum for one hour minumim).

 

[TrentNell]

never used the air powered let us know how it works, 1 hr is fine moisture boils out quick under vacum

 

[bullfrogjohnson]

I ahve used air ones just makes sure you let it pull down for a while

 

[Cougar281]

Well, I had it on last night... The odd thing is it seems to work for the most part, but randomly, it starts to loose vacuum, and it actually started to put some pressure in the system . 10# or less, but still... I'm going to stop by and exchange it and try again. I noticed a change in its tone, and saw that it was loosing vacuum. I know it's not a leak in the system, because after shutting it down with about 25inHg and leaving it sit for 30+ minutes, it still had the same amount of vacuum... While the compressor was running continuously, it never dropped below 120# in the tank (regulator was at 75, which was the vacuums recommended pressure). I'll see if it's the same tonight.

 

[Cougar281]

Well, it seems like the problems I had last night may have been caused by moisture in my compressor. I exchanged the vacuum and tried again; this time it started doing it again, but I was watching it ad shut it off at the manifold before it dropped far below 20inHg. Noticed that the vacuum was wet. When I then drained the tank at the hose with a air nozzle, I could see the moisture. Dumb thing is I have a air/water separator on it, but it doesn't seem to do squat. It seemed to work better after I drained the tank (there was a fair amount of water in it ) and moved the A/W separator to the end of the hose, although it still didn't seem to be doing anything. Any suggestions for a decent but not break the bank separator?