.If your bicycle pump fails to generate sufficient pressure, first, make sure that the connection between the pump body and hose is tight. Next, remove the hose and block one end with a finger. If you can blow air through it from the other end, the hose is leaky and should be replaced. If the pump still does not work, follow the steps shown below. Unless the washer is damaged, clean and reuse it; a replacement may not be available.
1. Pull out the pump handle and unscrew the threaded cap. Then, remove entire plunger assembly from pump body.
2. Unfasten screw holding washer to pump shaft. If washer is not torn or badly cracked, wipe it clean with a damp sponge; it can be reused.
3. Soften a stiff washer by working oil into it with your fingers. Remount washer with convex side to pump shaft, and fasten the screw.
4. Fill washer cup with light grease Insert plunger assembly into pump body at an angle and twist. Screw on threaded cap firmly.