TO RENT OR TO BUY... that is the ..
 

.... question. Redoing my evap on my SL500 and pretty soon changing my compressor on my 560SL. Local O'Reilly has them for rent for $400 with history unknown. On the other hand, I can get my own , brand new for the $200 +/- neighborhood. I know this is such a minor thing to decide on but....what are your experiences on the rental units...

...just when you guys have time , I would appreciate the input.

Are we talking vacuum pumps for evacuation? Rental fee? I think a sentence or two got left off the post, but then again, I can be pretty dense. ;)

my mistake... Vacuum pump for evacuation. And that is correct- rental fee: $400.

With a $400 rental fee, buy this instead and let us borrow it ;)
http://www.acsource.com/product.asp?0=234&1=283&3=220

I'd be more than happy to rent you my yellow jacket evacuation pump for a weekly fee of $390 dollars.

Of course I think I only paid $220 for it a couple of years ago so it may not be the best deal for you - but I'll stand by my offer.

If you have an air compressor, Harbor Freight tools has a venturi-style vacuum unit that is made for this type of work. It's about $15.

Venturi type....wonderful idea.... good results????

No. Venturi-generated vacuum is fine for sample drying in chemistry lab but is incapable of generating the > 29" Hg vacuum necessary for A/C system evacuation.

The Harbor Freight tool vacuum level is listed at 28.3" Hg, requires two minutes to reach that level internally (before being connected to an A/C system) and uses 4.2 cf of air per minute. An air compressor of appropriate capacity is necessary just to power this.... and lower air flows will result in even poorer evacuation. Regardless of the length of time run, this venturi pump is incapable of reaching the level of evacuation needed.

Invest in a proper vacuum pump... it will pay for itself in the long run. And buy several spare quarts of pump oil... rotary vane pump efficiency falls off as the oil absorbs water vapor and debris scavaged from the system.

Another DIY option
 

Find an old refrigerator or dehumidifier and salvage the motor/pump assembly as a vacuum pump. I've done a few jobs that way.

Forget the rental.

rental issue solved
 

...a good friend of mine borrowed an electric vacuum pump from a shop for me..Now, how do I attach the pump to the gauges then to the car?????Which valves should I open or close???
Boy do I need directions!!!! Thanks for the help.

Here is an entire AC evacuator system on Ebay for $88 and 8 hours left
EBAY

.... i use 134 A. And all I need now are gauge set up instructions to vacuum the system. Thanks for the info, TX76513.

I bought a set of manifold gauges, and frankly I rarely use them. When charging into an empty system, I usually charge to vent temperatures. When the vent temperature stops dropping, I know I've put enough refrigerant into the system.