Craftsman 1 gallon direct drive oil filled wont build air pressure

most likely a problem reed /poppet valve in the compressor heads

When you say it does nothing do you mean the motor wont come on or the motor comes on and it wont build pressure? if the motor comes on, there are several possibilities:
1. The unloader valve is stuck open
2. The valves in the head are bad
3. The flywheel is loose
If the motor wont come on, the pressure switch is bad (which holds the unloader valve open)
http://www.mastertoolrepair.com/air-compressor-parts-vt6362-p-60727.html

I can not find a Craftsman compressor with that model number anywhere so here are a couple things to look into. If the compressor fills to 70psi and keeps on running check the valve plate and piston/cylinder assemblies. Check that the valve reeds on the valve plate are not bent, broken or warped from heat. Then check that the wiper (oil less) or pistion rings (oil splash) are not damaged and that the cylinder wall is not scarred up. Any of these will let the compressor fill up to the point where the air pressure leaks past the valves or piston and won't fill any further. If the compressor fills to 70psi then shuts off the problem is in the pressure switch. Some have an adjustment screw or bolt to control when it turns on and shuts off. If you had a drop from 100 to 70 the springs may be weak or broke and you'll have to replace the switch.

Hi Jim,

Disconnect your main air supply from the comp head to the receiver/tank and see if their is a reasonable air supply to atmosphere.

If not check that air is being taken in by the head intake filter

John

Check for a leak between you compressor head (pump) and your tank. Your pump output may be good but as your tank pressure gets higher the leak will not allow the tank to build up.

Sounds like the compressor has failed -- probably the valve -- tear down and rebuild is probably the solution, or replace compressor, or just buy another unit. My nature would be to tear it down and see what's going on.

my ace air compressor which is 26 gallon 5 hp will not get over 60psi what is wrong with it please?

have a 26 gallon air compressor , changed regulator switch but it still wont shut off

The pressure switch has snap action contacts that are opened by a diaphragm pushing against a spring mechanism. Unplug the compressor and remove the cover to the switch and look for the contacts. Make sure that they are not welded together from use. Move the on/off lever to see if they open and close. You may have welded contacts or broken mechanism within switch. A factory replacement is expensive, however if you are a tinker-er you can use a lower price generic pressure switch available on ebay. Switches are sold by pressure range, you need a 120#. Fittings may need tweaking. Enjoy