a) Air leakage from the pneumatic system. b) The inlet/outlet spring of the air pump valve is damaged. c) The piston rings and cylinder liner of the air pump are seriously worn. d) The air pressure gauge is faulty. e) The safety valve does not close tightly or is faulty.
a) Check and correct the faults. b) Replace the broken springs with new ones. c) Replace them with new ones. d) Correct it or replace it with a new one. e) Check or replace it.