Vacuum pump gave up!!

After hours of work changing my truck's AC over to R134, I find that my vacuum pump stopped working. I lover this pump! Weighs about 60 lbs.
Consists of a refrigeration type sealed motor inside a cabinet. The on-off switch has a spring loaded "start" position. Motor has a 130-156 mfd capacitor strapped to the side. In the "on" position the windings hum until the cutout kicks in a few seconds later. Turning to the "start" position does nothing. I tried replacing the capacitor with 2 old ones from my abandoned house AC unit. Unit ran until 1 year ago, and both compressor and fan ran when abandoned. No luck.
I'm guessing that somehow the rotor (armature?) is jammed due to Northwest corrosion. Tried bumping the unit with a rubber mallet while starting.
Anybody have any ideas on how I can revive the starter windings, or whatever?
Hate to say goodbye this unit. Paid a lot of money for it (used), but, did get 35 years of use.
Thanks for all ideas.
Ivan Vegvary
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Ivan Vegvary wrote:

Cheez, Ivan, you're like me. You expect things to last forever!
I remember being a bit ticked when my Taiwanese band saw motor crapped out after 19 years.
--
Gary Brady
Austin, TX
  Click to see the full signature.
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wrote:

Is this an old hermetic compressor that was repurposed into a vacuum pump? Thank it for it's many years of service and go get a new one.
The modern oil-ballasted vacuum pumps go on sale for under $300 for 1/3 HP units this time of year - with a warranty and everything. And you can get bigger ones if you're in a hurry or working on big supermarket systems with 200' line runs.
You can shop pawn shops, but...
--<< Bruce >>--
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for many years my dad used an old refrigerator compressor.He put a hose with a clamp on the suction side and hooked it to his gauges.Worked great and it was practically free.
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I did pretty much the same with a compressor from a 5000 BTU window shaker. I built it into a five gallon paint bucket. Been using it for years (occasional service only) and, sealed inside that paint bucket, it stays like new.
Vaughn
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Vaughn - how do you lubricate the pump? Reportedly, a system that was originally closed requires some method added when the input/output are open. Maybe you've found this not to be true?
Hul

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I understand that the compressor constantly (but gradually) loses its original lube oil as the thing runs. First, I have never seen any evidence of oil loss. And second, I only need to use the thing occasionally. I guess I have had the same one for ten years now. If it dies before I do, I will just scrounge another free compressor from another rusted out window unit.
Don't get me wrong, a "real" vacuum pump lasts longer and pulls a deeper vacuum (though my guages can't seem to tell the difference). That said, my lash-up has served my needs perfectly.
Vaughn
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Thanks. Good to hear that's worked well.
Hul

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Ivan Vegvary wrote:

Did you change the oil when you put in the 134?
The only way I know to break free a bad pump is to wack it with a 2 x 4 at the same time you put the power to it. You can double the size of the start cap. to get more torque on starting. Another way if you have 3 phase is to put the other phase on the start winding and bump the power on and off. The problem is that it won't last too long after you do get it running.
John
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So, is it true to say that the pump would not start at all today, or did it run today and then stopped working.
If the former is true, then it may be seized. I had a similar problem with a HVAC pump. I took apart the pump somewhat and found it seized (no problem with motor). A strong helping with a wrench got it to turn. It worked fine afterwards. You may need to take it apart and clean rust on vanes.
i
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