Lindsay 80 air compressor

SOURCE: WILL NOT BUILD PRESSURE

Many craftsman compressor are built by champbell hausfeld using a dry type of cylinder and piston (no oil, no crankcase). If dry type, check for worn cylinder and piston ring. Pieces of the vinyl ring can jamb between the reed valves in the head causing air to escape from the intake. If your compressor has a crankcase and oil, check for broken reed valves in head. Spray soap solution on hoses, checkvalve, drainvalve, and fittings to check for leaks. Most likely problem is reed valves broken or open. Parts are available from sears or match parts to chpower.com. enjoy

SOURCE: Twin tank air compressor does not pressurize past 65 to 80 psi.

machine inlet valve not sealing in cylinder head valves need to be removed for assesment

SOURCE: Air leakage through pressure switch needle

1)Let your unit pump up.
2)Turn it off.
3)Find the supply line from the pump to the tank.
4)Remove the supply line from the pump head.
5a)If you hear air coming from the tank you have a bad check valve.
5b)If you do not hear air coming from the tank, you have a leaky
pressure switch.

SOURCE: Compressor is having trouble sustaining pressure. No leaks.

it has to be leaking some where check Liquid soap check the intake filter.

SOURCE: I have a Porter Cable

I believe you have a head valve or piston ring problem. The parts you replace are suppose to leak. It is a safety feature that doesn't allow the motor to burn up before the pump warms up. Kind of like a soft start feature. If you look on the breakdown part number 107 Kit Valve Plate is what you need to inspect. Sounds like your valve plate is either worn or damaged. If you go into the pump you will have to get part 103 also which is a gasket kit. Or you can try to salvage the old gaskets.
If the valve plate is ok you will need to inspect the rings that go around the pistons. Some times you will get one that gets brittle and breaks off scarring the cylinder. Look for these two things, I am pretty sure one of them is the problem with your compressor.