Pic. 3-10. Checking the tightness of the rear sealing ring: 1 - main cylinder; 2 - vessel; 3 - adapter with seal; 4 - pressure gauge; 5 - tee; 6 - adjusting screw; A - air from the compressor; B - air outlet
Check the air pressure on the pressure gauge, which should be in the range of 0.05-0.08 MPa (0.5-0.8 kgf/cm2). If the pressure is less, replace the rear O-ring.
Checking the tightness of the front sealing ring. Install the master cylinder on the stand and connect it to a vessel filled with hydraulic fluid and to pressure gauges (pic. 3-11).
Pic. 3-11. Checking the tightness of the front sealing ring: 1 - screw for pumping; 2 - crane; 3 - pressure gauge with a division value of 0.2 MPa (2 kgf/cm2), 4 - pressure gauge with a division value of 0.005 MPa (0.05 kgf/cm2); 5 - vessel; 6 - pusher; 7 - master cylinder
Close the valve of the pressure gauge 3 and, by moving the pusher of the main cylinder, ensure a stable pressure of 0.2 MPa (2 kgf/cm2).
With the pusher fixed and no fluid leakage, the pressure should remain constant for 2 minutes.
Close the valve of the pressure gauge 4 and open the valve of the pressure gauge 3 By moving the pusher, set a stable pressure of 10 MPa on the pressure gauge (100 kgf/cm2).
With the pusher fixed and no fluid leakage, the indicated pressure must remain constant for at least 2 minutes. Otherwise a forward sealing ring replace.