Causes

• Air leaking by air cylinder internal piston
• Control valve leaking
• Air hose leaking

Test

• Check air cylinder rod seal for leaks
• Check air cylinder for internal leak by removing air hose fitting on end of air cylinder which is bottomed out and listen for air escaping - if air is escaping after hose removal, air is by-passing internal piston
• Check airline for leaks with soapy water

Solution

• Repair or replace air cylinder, air valve or air hose, whichever is found to be cause of problem.