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Guys I need your help, My problem is about my compressor its psi drops from 40 to 22.i check all the connections and they are all fine and sealed properly .Is it the compresor itself that gave in after almost 2yrs of use ? or I just need to fix something.Im planning to buy a new one as a replacement if that is the case but if not then Im very willing to try to fix it with your help and advice.more power and thanks.

things to check!
1 drain valve
2 if it is a diaphram - the rubber seal could be shot - replace the assembly
- give us more info -Is it a Cambell hausfield? does it have a tank? does it have a seperator?

When does the pressure drop?

Does it take exceptionally long to build up the pressure?

How big is the compressed air tank?

thanks for your response,I have a generic compressor made in taiwan i bought it at model expo 5 yrs ago it has no tank and I believe its piston type , for five years the max pressure is 40 psi and when in use bet. 18-22 psi but now when i turn it on the max pressure is only 22 psi and when in use 12 psi, I dont know if this is enough psi to paint the body of a tank 1/35.thanks

Since you don't have a tank, the most likely cause would be your rubber diaphram the build the pressure is leaking somehow. It must be a very small leak otherwise no pressure would build...You might end up spending more to get parts and fix, then to by a 2 gallon new cheapy compressor

propboy is right

Thanks again guys,