Trouble fixing an air compressor

[Jimmy]

I was hoping that someone in this newsgroup might be able to help with this problem. I recently inherited an old Sears 1hp air compressor from the

1970's -- (model 160.171140). It wasn't in great shape but since I don't have one, I thought it would be great to fix up for the shop (this was back when Sears/Craftsman made decent tools right?). Anyway, I ordered the replacement parts from Sears at greatly inflated prices and they arrived today. They are not identical to the ones that were originally on the compressor, not that I expected them to. Most of the pieces worked out ok--the check valve was identical, gaskets fit great, shut off and safety valve is different but checks out (actually made of brass instead of the original plastic!) but the pressure switch is giving me some trouble...

It is a Square D Pumptrol Pressure Switch (I have the model and specs if that will help) and on the underside of the swich is attached a valve with four threaded holes in it. The one on the bottom is where it attaches to the shut off/safety valve, but I don't know about the other three? They are all connected so the tank wont hold any air. Can I get some covers or plugs to fill them all? On the old switch, there was a guage that showed the psi in the tank but this new one does not. Should there be another valve or guage threaded into the pressure switch? I'm a bit worried that if I simply plug those holes, the motor won't know when to shut off? Is that how it works?

I would really appreciate any help you could give me on this problem. I dread having to call sears for assistance since I don't really have half a day to wait on the tele just to talk to someone who has no idea what they're talking about so they can tell me that I need to schedule a service call!!

Thanks Jimmy

[Greg Millen]

Around that era the compressors were rebadged Campbell Hausfields. I got parts and a diagram from them.

[Ba r r y]

You can get plugs and even a gauge at Many hardware stores, Lowes, Home Depot, Grainger, etc...

Bring the switch with you so you can select the proper parts, and don't forget the teflon tape.

The switch should connect between the tank, the pump, a safety valve, and the regulator. You have a regulator, right?

Barry

[RonB]

Did you check the drain plug at the bottom of the tank for leakage? Older compressors are prone to rust-out and leaking in this area. Best check is the old soapy water and brush check.

[Jimmy]

Yes, remarkably, the drain plug is absolutely fine. The problem was the check valve leaking and the on/off turn valve did not close tightly. That being said, I have already ordered the replacement parts (plus a few others just to tidy things up). My question is concerning the shut off/safety valve that has "too many holes".

[Jim Behning]

[dicko]

I dont have that particular model but the manifold on mine has: the pressure swtich on the top the tank on the bottom outlet hose in a lower hole on the side tank shut off in a lower hole opposite the hose pressure gauge in an upper hole safety pressure-relief switch in the other upper hole opposite the pressure gauge.

You'll have to look into the manifold and examine its internal structure because it does make a difference where the parts are screwed in. I sent it to Sears for repair once and they put everything back together in the wrong spots. The pressure gauge read the pressure in the hose, after the shut off valve, rather than the pressure in the tank before the shutoff valve.

BTW, I found that the local ACE hardware store carries a complete line of compressor parts.

dickm