Repair a Sanborn Model 500A60 belt drive air compressor

I am trying to repair a Sanborn air compressor Model 500A60 belt drive. We got a number of leaks fixed then noticed the belts were loose then its pulleys wouldn’t spin.

I slid the motor back away from the compressed air pulley and got the belts pretty tight (1/4 in of play). The pulley had a little trouble spinning so I turned it manually and was able to get it to start and run for awhile before the pulley bogged down and then the breaker blew.

Are my belts too tight? OR are the bearings for that pulley needing some kind if lubricant?, says Jack Strack.

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Hello Jack.

You said ” I slid the motor back away from the compressed air pulley and got the belts pretty tight (1/4 in of play).” That’s too tight. It likely needs new belts.

Left as is, you’ll get bad bearings before long. Belt play should be 1/2 in at the middle with finger pressure.

“The pulley had a little trouble spinning so I turned it manually and was able to get it to start and run for awhile before the pulley bogged down and then the breaker blew.”

You mean the motor needed a push to get going?

If so check the capacitors under those humps on the motor. Might be one or both from the sound of it.

Check it out and let us know, will you? Good luck. Doug.

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Thanks so much! The motor pulley turns with no problem but the pulley on the compressor part wouldn’t turn without prying it a bit to nudge it loose then both pulleys turned for awhile.

1 question: – Any idea where to get belts for something that old? Thanks, Jack.

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If it has a number on it, you might try looking for that online. There might even be something close enough at an auto parts store – ya never know…

Then if no luck, try measuring it and look for similar belts – possibly in a range that you can deal with by moving the pump or motor. Meanwhile, if the belts are not completely shot, you might be able to clean off the glaze with some steel wool or emery cloth.

Again, best of good luck… Doug.