I picked up a horizontal craftsman compressor at a yard sale. Looked in good shape. Runs on 220v. I had to add a regulator. Interesting as I got on to post and saw another craftsman compressor question.

The compressor runs fine but when it reaches cut-off pressure the motor stops but air leaks out of a valve attached to the shutoff regulator. The valve has a tube attached to it that goes to the head of the pump. Friend of mine had an exact replacement pressure switch. I tried that one and got the same results. What is also interesting. If you shutoff the compressor with that switch it allow air in the tank to bleed off via that valve. At first I thought that was by design for that compressor. When you flip the off switch something in the switch moves a tab that opens that valve.

I wonder what that line and valve do that goes to the head of the pump? Many other compressors I have looked at have this feature. I figured it was some safety feature.

I wonder what is wrong here. Could I have two bad switch regulators? As stated once compressor reaches shut-off point the motor stop and air bleeds out that valve until it hit the turn on pressure. Seems like this is realted to flipping off the power switch as it produces the same behavior. I had thoughts of replacing this switch regulator with a newer one by using a current model number compressor in Sears. I already got part numbers to change the air intake foam with a round unit that bolts on to the intake air and has a twist off cap that allows for a replacement auto type air filter.

Craig