If that happens, the air that is supposed to be pumped down into the tank, simply flows back and forth inside the pump, and the air pressure in the tank stalls.
I get more and more questions from owners of DIY type air compressors about getting gaskets to repair their compressors. This fellow has an air compressor that is only 8 months old, yet he is told by the manufacturer that no spare parts are available any more.
I suspect in that case there were never any spare parts for this compressor from the get go!
What is to be done, then, when you need to replace a gasket in your air compressor pump but that gasket is no longer available?
They acquired some gasket material, often from an auto parts supply shop.
A compressor pump head gets very, very hot in operation. When sourcing replacement gasket material, recognize that. Yes, you can burn skin with the heat generated on a compressor pump, so any gasket material has to be heat resistant.
Here is an example of a typical pump head, separated into parts, and you can see where the gasket on this pump goes.
After disassembling the pump head they located all the gaskets. They then either removed them to use as a template to make new ones, or used the surface where the original gaskets were installed as a template, if the gasket was beyond removal in one piece. With the old gasket template as a guide, they marked the new gasket material appropriately, and cut the material to suit.
If your air compressor won't build pressure past a certain point, the most frequent causes seem to be either the intake or high pressure reed / flapper valve is failing, or a gasket is letting go. You may, nor may not, be able to see the failure point if it is the gasket. Yet, once you have the pump apart, you might as well eliminate that as the potential problem, by installing new gaskets.
If your compressor supplier tells you that gaskets for that compressor are no longer available, then making your own is the logical choice.
Writers into this site have suggested that the following is a good source for compressor gaskets material. I have not dealt with the company myself so I cannot comment from personal experience.
They are a wholesaler, so I doubt that you can buy from them directly. You will be able to identify the material you need, and find your closest distributor through them, however.
Good luck building your own compressor gaskets.