A/C gearheads, what do you think? - PeachParts Mercedes-Benz Forum

nickofoxford · #1 03-04-2009, 09:35 AM

I found this Medo vacuum pump online, pretty cheap too. Do you think this would work to pull vacuum on my A/C?

Here's the link:
http://www.alltronics.com/cgi-bin/item/23Z018/PMP/Medo-VP0625-V1014-D2-0511-vacuum-pump

Oracle12345 · #2 03-04-2009, 09:37 AM

to pull a vacuum on your A/C you need an A/C recharge machine which costs at least a grand for a used one and new one is like 2 to 3 grand.

this will work too

http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=11447&group_ID=1523&store=snapon-store&dir=catalog

http://www.sjdiscounttools.com/rtirhs680r12.html

is more what your lookin for

http://www.sjdiscounttools.com/rtiac800.html

that plus a freon identifier

rrgrassi · #3 03-04-2009, 10:18 AM

You can by an A/C specific pump for less than that.

tankowner · #4 03-04-2009, 12:11 PM

I have pulled a vacuum on my AC before - you can go about it two ways. Go to harbor freight and buy a cheap Venturi type adapter (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92475) if you have an air compressor to attach it to. (This is probably the less desirable of the two, but cheaper if you have a compressor - I have never done it this way though, so ask others if you go that route.)

Or, buy a standard vaccum pump - here is one that even comes with a gauge set . . . http://sector29.com/PRODUCT_PAGES/316/316-FJCKIT6.html. This is the type of set up I use and it works quite well.

Just be sure you are familiar with how the gauges work, etc - especially when adding the R-134a. Haynes has a nice AC/Heating manual to referece if you haven't done it before - probably find it in your local. library.

vstech · #5 03-04-2009, 12:55 PM

uh, there's no way anyone in the DIY field is ever going to need anything like that recharge stataion.
a standard vacuum pump and a set of gauges is fine.
a good scale to weigh in the charge helps. this is assuming the system leaked out all the freon, and you are recharging the repaired system.
Idealy you need a reclaim system, a nitrogen pressurization system and a vacuum pump.
...
good luck with that.
any decent vacuum pump will do fine if you change the dryer.

KAdams4458 · #6 03-04-2009, 02:14 PM

Quote:

Originally Posted by vstech

...
any decent vacuum pump will do fine if you change the dryer.

Which should be changed on principle, anyway.

Also, I gotta highlight the decent part of your statement. The pump that the OP linked us to says... Medo Vacuum Pump 115VAC 'Model # VP0625-V1014-D2-0511 Rated 9.84 in. HG

That isn't enough. I recommend the Harbor Freight electric option. Or... If you're creative, do what I did and simply reclaim an old refrigerator compressor. A little epoxy, some adapters, and a power cord gets you a vacuum pump for cheap. Mine will pull down to a verified 29.5 - A pretty good deal for an hour of work and $20 in parts, including the compressor.

vstech · #7 03-04-2009, 02:21 PM

yeah, I want -150microns of vacuum for my service trucks...
that's below 29" HG...

lvfast1 · #8 03-04-2009, 03:26 PM

I do Hvac by trade and a 5cfm or 7 cfm is adequate for residential/commercial systems 1.5-3 cfm more than enough for automotive a/c if you leave it on long enough with no leaks...micron guage would be nice but not necessary if no leaks and proper manifold setup and digital scale to weigh in correct charge <-(very important on cars)...definetely dont need evac/recharge system especially if it happens to not have "any" charge

when you start no recovery needed...i look on ebay quickly found many that would work...Hvac supplier in your area should sell them also..wholesale if you have a contractors license...JB and Robinaire are good brands for everyday use but a cheapy fine for what the average DIY automobile owners need.

http://cgi.ebay.com/JB-Industries-DV-142N-Fast-Vac-HVAC-Vacuum-Pump-5cfm_W0QQitemZ310125939114QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item310125939114&_trksid=p3286.c0.m14&_trkparms=66%3A2%7C65%3A15%7C39%3A1%7C240%3A1318 <-great unit good brand

http://cgi.ebay.com/ebaymotors/Refrigerant-Vacuum-Pump-1-5CFM-for-Automotive-HVAC-R_W0QQcmdZViewItemQQ_trkparmsZ66Q3a2Q7c65Q3a15Q7c39Q3a1Q7c240Q3a1318QQ_trksidZp3286Q2ec0Q2em14QQhash Zitem250379900114QQitemZ250379900114QQptZMotorsQ5fAutomotiveQ5fTools
^-will work for automotive but will have to run a while to acheive desired vacuum but economical.

Hope this helps

Arlo

lvfast1 · #9 03-04-2009, 03:37 PM

Sorry,thought of something else autozone sells them for $200 ouch but i dont know about pennsylvania but here in las vegas they are in pawn shops, flea markets, and the newspaper classifieds maybe try those for less $$$ good luck..

Arlo

derburger · #10 03-04-2009, 03:54 PM

Alternatively, you could find a used charging station. I picked up this one with a nice built in vacuum pump, gauges and hoses I used on my car for $50. It's a decent rolling toolbox too.

kingdoc1 · #11 03-04-2009, 05:54 PM

The old refrigerator compressor is the way to go--old refrigerators are cheap if not free and all you need is a fitting that will attach to the hose on your manifold gage set and some epoxy or solder and you are in business. Plus, when it quits working, you don't feel bad taking it to the dump where it was headed in the first place!

KAdams4458 · #12 03-04-2009, 06:00 PM

Quote:

Originally Posted by derburger

Alternatively, you could find a used charging station. I picked up this one with a nice built in vacuum pump, gauges and hoses I used on my car for $50. It's a decent rolling toolbox too.

Awe, man. There's gonna be some sour grape action up in here.

I could have one-upped you, but I passed on buying the reclamation system that a local pawn shop had for $150. I seriously thought about it, because I'm really supposed to use one, but figured to heck with it. If I need to drain an r12 system, I'll just let a shop suck it out. It's worth money to them, and saves me the trouble of maintaining yet another piece of equipment. Besides, I have plenty of virgin refrigerant on hand.

Scott98 · #13 03-04-2009, 06:13 PM

Quote:

Originally Posted by lvfast1

I do Hvac by trade and a 5cfm or 7 cfm is adequate for residential/commercial systems 1.5-3 cfm more than enough for automotive a/c if you leave it on long enough with no leaks...micron guage would be nice but not necessary if no leaks and proper manifold setup and digital scale to weigh in correct charge <-(very important on cars)...definetely dont need evac/recharge system especially if it happens to not have "any" charge

when you start no recovery needed...i look on ebay quickly found many that would work...Hvac supplier in your area should sell them also..wholesale if you have a contractors license...JB and Robinaire are good brands for everyday use but a cheapy fine for what the average DIY automobile owners need.

http://cgi.ebay.com/JB-Industries-DV-142N-Fast-Vac-HVAC-Vacuum-Pump-5cfm_W0QQitemZ310125939114QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item310125939114&_trksid=p3286.c0.m14&_trkparms=66%3A2%7C65%3A15%7C39%3A1%7C240%3A1318 <-great unit good brand

http://cgi.ebay.com/ebaymotors/Refrigerant-Vacuum-Pump-1-5CFM-for-Automotive-HVAC-R_W0QQcmdZViewItemQQ_trkparmsZ66Q3a2Q7c65Q3a15Q7c39Q3a1Q7c240Q3a1318QQ_trksidZp3286Q2ec0Q2em14QQhash Zitem250379900114QQitemZ250379900114QQptZMotorsQ5fAutomotiveQ5fTools
^-will work for automotive but will have to run a while to acheive desired vacuum but economical.

Hope this helps

Arlo

+1. The cheap Harbor Freight pump is a piece of crap and will never sufficiently boil off your moisture. I bought a 1.5 cfm vacuum pump for about $135 which is all you need for a car. You just need to run it a little longer than a higher cfm pump.

Scott

leathermang · #14 03-04-2009, 08:48 PM

Quote:

Originally Posted by Scott98

+1. The cheap Harbor Freight pump is a piece of crap and will never sufficiently boil off your moisture. I bought a 1.5 cfm vacuum pump for about $135 which is all you need for a car. You just need to run it a little longer than a higher cfm pump. Scott

Ditto.

How many times have we posted this information ? There are huge threads which spell out what will and won't work properly in the long run. AC service is expensive and not much fun. A well serviced system ought to go 6-8 years before any refrigerant has to be added... this does not mean it has an unintentional leak... the front compressor shaft is made to have some leak in order to oil the front bearing. So some recharge is expected over time.. but a LONG time ... and this is why the system should be started up every month including in the winter.

Then someone will post that they used one of those venturi types and it worked fine..

What they won't tell you is that moisture left in the system by less than great vacuum procedure ( and failure to flush ) takes some time to do its damage.... perhaps a year or more... the mixing of the water with the oil and refrigerant makes acid which eats away at some of the interior metal parts... they then flake off and accumulate in the worst most important tiny places...

KAdams4458 · #15 03-04-2009, 09:04 PM

Oh my. When I recommended the Harbor Freight option, I failed to check the site, and see now that they have more than one. The cheap one I can't vouch for, but the more expensive one I will vouch for. They work, and I've seen it. The big one is on par with my ancient salvaged refrigerator compressor. Well, the one I have some experience with was... As with anything Harbor Freight sells, it's hit or miss. Sometimes you have to go through two or three returns to get one that actually works properly.

Edit: Wait a second... I'm still wrong. That isn't the same pump at all! The one I'm talking about is a two-stage pump. Looks like it's special order only, now.

I'm at least 90% positive that this is the exact model I've seen in action. http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=66467