# Questions about a 26 year old air compressor



## vladv101 (Jun 20, 2020)

*Hey there!*

I am in search of some insight about this air compressor, I have a Sears Craftsman 4HP 25 Gallon Air Compressor (Model 919152920)
Single cylinder, Oil-less, 26 years old

I was planning to use it for a paint job using a HVLP spray gun but after trying to build a full tank. Halfway of filling the tank up, the air compressor cut out and tripped the breaker. I restarted the outlet and re-plugged the air compressor and let it keep running (I originally thought the outlet was the issue). After a minute of the air compressor running, it cut out again and this time, the breakers didn't trip and the outlet was still going meanwhile the air compressor tripped a overheat switch I believe (Not sure, just speculation because after 5-10 minutes the compressor started just fine again). So what my question is, can the compressor be rejuvenated? I took apart what I believe is the cylinder and both of the gaskets looked just fine and no tears or minor rips. The plate and cylinder did have some tar looking stuff on it but other than that it was relatively clean. One thing I also noticed is that the small circle filter was missing (Not sure if that makes a big impact on the compressor efficiency or not). If this compressor can be fixed and work like new, what steps would I have to take to diagnose or rebuild to bring it back to it's prime time?
(Pictures Included for reference)



*Gaskets & Plate*









*Cylinder Top & Sleeve*









*Close-ups*



























*All the knowledge is appreciated!*
(Note: I'm not inclined in this subject so excuse me if I said something incorrectly!)
Thanks!


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## stevon (Mar 5, 2019)

*vladv101*
Your issue seems to be the electric motor driving the pump. Are the windings burned? do they "smell" burned. Are the run and start capacitors working? I don't see any mechanical problems in the pump section. Are the ball bearings turning smoothly? How many amps is the compressor drawing at the top pressure just before it turns off? an air compressor is a simple machine but there are parts that need maintenance after 26 years e.g. filters, check valve in tank, etc.

Stephen


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## vladv101 (Jun 20, 2020)

stevon said:


> *vladv101*
> Your issue seems to be the electric motor driving the pump. Are the windings burned? do they "smell" burned. Are the run and start capacitors working? I don't see any mechanical problems in the pump section. Are the ball bearings turning smoothly? How many amps is the compressor drawing at the top pressure just before it turns off? an air compressor is a simple machine but there are parts that need maintenance after 26 years e.g. filters, check valve in tank, etc.
> 
> Stephen


Nothing. The bearings are good and its smells just fine.


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## stevon (Mar 5, 2019)

How many amps is it drawing at top air pressure just before the pressure switch shuts off the compressor? Ammeters can be bought for cheap, a harbor freight one will work fine

Stephen


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