My craftsmen air compressor wont build pressure. How do i fix it?

Depending on compressor it may be cost effective to replace it.
Try this link
https://fix-my-compressor.com/compressor-will-not-build-pressure/

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

My compressor runs for about 5 min and shuts off.....does any one knows what could be the problem?

thanks

Oil free pumps do tend to blow the piston ring (not too expensive) available at searsparts.com. Remove covers to pump and manually turn crank until piston is at top and look at the condition of the cylinder neer top, If it looks scratched, order cylinder kit with piston ring. If it looks good and shiney, could be the valve plate in the head. There are reed valves that tend to break. Run pump however with covers removed and check with soapy water for air leaks and repair as needed (air leaks under the cover will prevent unit from filling). Good luck

Your unit should fill within 5 min. Compressor may have worn cylinder or just leaking. Easy test. Spray soapy water on all connections/fittings including drain valve and regulator while compressor is running. Repair as needed. If no leaks, remove plug from outlet, remove cover and examing cylinder. Turn crank by hand till piston is all the way up into cylinder. Examing carefully the condition of the cylinder close to top. If the cylinder is scratched or worn then pressure is leaking between piston/cylinder and will not fill tank. Replace cylinder kit available at Sears, cost under $50. Good luck with your project.

could be a gaskit or the inlet reed

Well try emptying all of the fluids, cleaning it out with carb cleaner then high pressure air. Maybe debris caught in there.

The check valve is most likely the problem,or the compressor is bad.The check valve actually holds the air in the tank,without allowing the air to retreat backwards into the compressor.

sounds like the regulator is fualty.

Check the reset button on the motor to see if it tripped. The motor may be overheating. Some motors have an internal breaker and they have to cool off before they restart. Also check the pressure switch. Move the switch back and forth ( on and off ) and listen for a click. If it doesn't click with low to no air pressure then the switch is bad.