A/C Vacuum Pump Question

Hugh R · 08-23-2004, 07:30 AM

Anyone have any thoughts on this Mastercool vacuum pump, which is air powered. Its cheap about $50, and I only plan on doiing this kind of work once in a blue moon. My compressor easily has the needed capacity.

Here's the link http://www.acsource.com/index.asp?PageAction=VIEWPROD&ProdID=223

david914 · 08-23-2004, 08:04 AM

My $0.02... I would get a "real" vacuum pump as opposed to the air compressor driven style. I haven't heard any good things about the venturi-style vacuum pumps. For starters, your compressor will have to run pretty steady for the 2 or so hours that you'll want to pull a vacuum. For another, I haven't heard of anyone that was able to get as good a draw with a venturi type pump (not as much vacuum). Again, just my 2 cents worth.

Joeaksa · 08-23-2004, 08:07 AM

Hugh,

Totally agree with David. I found a good used vacuum pump on Ebay for $75 or so and it works very well.

The idea of having my air compressor run for hours at an end is not something that I want to have, so the choice was easy. These "quick and dirty" tools usually do not ever work as good as they are touted and in the end would cost you more money and time than doing it right the first time.

JoeA

Jim Sims · 08-23-2004, 09:32 AM

Get a real one and then loan it to your friends and have them also buy a quality tool the group needs. This is what my circle of Porsche friends do. Cheers, Jim

1974carrera · 1974carrera's Garage

If you want a no-cost alternative just use a compressor salvaged from a refrigerator or freezer. Solder the appropriate fitting onto the copper intake line of the compressor to hook your hose up to. Then carefully bend the discharge line of the compressor into a couple of loops so the compressor oil doesn't blow out. Voila, you now have a great vacuum pump!

RickM · RickM's Garage

Here's some detailed instructions on the conversion: http://www.sas.org/E-Bulletin/2003-12-12/labNotesAS/body.html

A trip to you town's recycling station should yield lots of potential donors.

You can also use an auto A/C compressor and electric motor in a similar way.

RoninLB · 08-23-2004, 06:42 PM

the refrig May be doable.. it really doesn't do the correct job.. That said I know plenty of guys who did this years ago.

scottb · 10:33 PM

Hugh:

I got a Harbor Freight ad in the mail today. They have their version of that pump on sale for $9.99. It's "Lot. No. 3952." If you're going to try that style pump, don't waste your money on the Mastercool.

You'll probably be able to score

this one for in the $75 range. I'll borrow it from you and give you a few bucks to defray the cost!

My $.02, FWIW.

RoninLB · 08-23-2004, 10:22 PM

Quote:

Originally posted by Jim Sims
Get a real one and then loan it to your friends and have them also buy a quality tool the group needs. This is what my circle of Porsche friends do. Cheers, Jim

I'm w/ Jim on this one.

I think we have a doctor around someplace?
I kinda remember some connection to Oregun?
It's not Superman.
I'll remember soon.

anyway he shoud grap a lab vacuum unit from maintence repair and then the rest is easy.

scottb · 08-23-2004, 10:46 PM

What's the minimum HP vacuum pump for a/c work? Will 1/4 HP do?

RoninLB · 08-23-2004, 11:20 PM

Quote:

Originally posted by scottb
What's the minimum HP vacuum pump for a/c work? Will 1/4 HP do?

my non pro opnion.

a lab 1/4hp will need about 8hrs if it was my car. Then it'll be squeaky clean inside.

dhoward · dhoward's Garage

Go to the local tool rental place. I rented one for $35 for the day.

Hugh R · 07:46 AM

ScottB--I'll try bidding on that one you showed me. Several rental places I called don't rent them. Even at 435/day, a less than $100 used from ebay may make sense. I'll let you know if I get one, and if I do, it will be available for beer rental in the Los Angeles area. Same with gauges which I'm definitely going to buy.

Joeaksa · 08-24-2004, 07:53 AM

Hugh,

If you use any tool twice a year, its cheaper and better to buy it most of the time. In this case you will also find a lot of new friends so IMHO its worth it!

JoeA

jdowty3 · jdowty3's Garage

You can get the same type at Harbor Freight for $15.
If you have an Autozone in your area, they have a Tool Loaner program and you can "borrow" a real vacuum pump. All you do is leave a $200 deposit and you get it back when the pump is returned.