extremely slow to build pressure

nannyandpoppyh usually, if an air compressor is taking long to fill it typically is either a seal problem, gasket failure, or an intake or pressure valve failing. First, I would do an overall check. Run the compressor and get a spryer you can fill with soapy water. Then spray some of the water on the tubes, the pressure regulator, and gauges. Also around the compressor head itself. See if the water starts bubbling, thus indicating and air leak. That would need to get fixed, of course. You would have to check the intake first to make sure that your compressor gets enough air. Then you can check the exhaust side and see if there is constant good pressure coming out of it. Remove the exhaust tube for that. It's best to do that with some pressure in the tank. The reason for that is, that if you remove the exhaust tube and you feel air coming from the tank side, you know that you have a leaky check valve which can cause prolonged fill time. If the intake and exhaust are okay. You'll have to "tear" into the actual compressor. Check the red valves and the compression rings.

Here is the user manual DC080100 Manual but it also has the parts list and part numbers. It will come in handy for any teardown you may need to perform.

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