DHS
Well-known member
I am thinking of building a homemade vacuum pump out of a old fridge compressor and just wanted to see pics of everybody. Also do they pull a deep enough vacuum to remove moisture for auto work?
Post you homemade vacuum pumps
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Charles (in GA)
Well-known member
Made me walk all the way back out to the shop to take the pics!
In the mid 1970's I was given a Kelvinator Sulfur Dioxide (SO2) refrigerant compressor from an old drink box (early '50's or earlier I guess), to use as a vac pump. It didn't have a motor, but my dad had a Craftsman diaphragm air compressor that no longer worked and we salvaged the 1/4 horse, 1750 rpm, Craftsman "Appliance" motor off of it, added a couple of 2x4's underneath and screwed casters to them, and viola! a vacuum pump. It has pumped down many a auto AC system, including the R134a add on system on my Ranger which I installed in year 2000. Yes, I have a set of 134a gauges, it shows 24" on them, and 27" on both of the R12 gauges I have, so I'm inclined to believe the older Robinair gauges. I've never had an issue with any of the systems I pumped down.
Tonight was the first time in several years that pump has run. I really need to give it a cleaning and put a new cord and plug on it.
Charles
In the mid 1970's I was given a Kelvinator Sulfur Dioxide (SO2) refrigerant compressor from an old drink box (early '50's or earlier I guess), to use as a vac pump. It didn't have a motor, but my dad had a Craftsman diaphragm air compressor that no longer worked and we salvaged the 1/4 horse, 1750 rpm, Craftsman "Appliance" motor off of it, added a couple of 2x4's underneath and screwed casters to them, and viola! a vacuum pump. It has pumped down many a auto AC system, including the R134a add on system on my Ranger which I installed in year 2000. Yes, I have a set of 134a gauges, it shows 24" on them, and 27" on both of the R12 gauges I have, so I'm inclined to believe the older Robinair gauges. I've never had an issue with any of the systems I pumped down.
Tonight was the first time in several years that pump has run. I really need to give it a cleaning and put a new cord and plug on it.
Charles
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diesel research
Well-known member
27" really isn't enough if there is a chance moisture got in there. (if system was opened or went empty)
Vacuum pumps are pretty cheap these days and pull deep vacuum.
If you told me you had plans to build a evacuation machine, I would be mildly amused.
Vacuum pumps are pretty cheap these days and pull deep vacuum.
If you told me you had plans to build a evacuation machine, I would be mildly amused.
Charles (in GA)
Well-known member
Given the prices I'm seeing on Ebay for the JB branded pumps mentioned in another thread.... I certainly could not recommend a homemade pump. Using my homemade pump, I have never experienced any problems with a system after pumping it down, nor later on, that could be attributed to moisture, so for the once each ten years or more that I might need it, I'll stick with what I have, but if I were considering a vac pump, I'd just buy one.
Charles
Charles
Thanks guys, I have a old re fridge compressor like yours that I have made a compressor out of, it is a small twin cylinder though. The few times I have done ac work I have always used my dads homemade vacuum pump that he made. My s10 I had to crimp a new line on to my fittings and that was 8yrs ago and so far no problems. At this point in my life money is tight and I hate to spend it if I don't have to. How far down of a vacuum does it need to pull in order to remove the moisture?
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Yep, my main vacuum pump is a 15+ year old JB but it will still pull a new system down under 400 microns in a pretty short time, when it starts taking a little longer it's time for an oil change( normally 8-10 new systems unless it's been real humid). I've worked on systems that were so wet that I had to change pump oil 3-4 times and run 2 pumps on for hours before returning them to service.