BarryB
Member
You might try checking a piston seal by first swinging the boom such that the "non-suspect" cylinder's piston is fully retracted, (or nearly so). Then pull the pin on that piston. Swing the boom (by hand) such that the "suspect" cylinder is fully retracted. Disconnect the hoses from the retracted "suspect" cylinder and cap the retract (rod side) port. Apply pressure on the bucket to swing the boom, extending the piston and forcing fluid from the rod side. (If you plan ahead and park the machine such that you are swinging to the "low side" it will be easier to do.) If the piston seal is leaking, fluid will bypass the piston from the retract (rod) side to the extend (piston) side. There is no hydraulic lock as the extend port (piston side) is open and this side has more space (volume) than the retract side. If you can swing the boom, the piston seal must be leaking. This is how I identified my leaking swing cylinder piston seal.