When testing the port relief valves with a hydraulic hand pump, slowly pressurize the valve. If the hand pump is pumped fast, the pressure will be altered by as much as 348 kPa (3,5 bar) (50 psi).
When testing port relief valves with a hydraulic hand pump, valve crack pressure should be observed.
A portable hydraulic hand pump will be used to test the work port relief valves. The hand pump must have clean hydraulic fluid that is compatible with Bobcat hydraulic fluid.
Blade Port Relief set at:
Base End (Item 1) [Figure 20-31-1] 27000 kPa (270 bar) (3916 psi)
Boom Port Relief set at:
Base End (Item 2) [Figure 20-31-1] 28999 kPa (290 bar) (4206 psi)
Rod End (Item 3) [Figure 20-31-1] 28999 kPa (290 bar) (4206 psi)
Auxiliary Port Relief set at:
Male Quick Coupler (Item 4) [Figure 20-31-1] 20595 kPa (206 bar) (2987 psi)
Female Quick Coupler (Item 5) [Figure 20-31-1] 20595 kPa (206 bar) (2987 psi)
Arm Port Relief set at:
Rod End (Item 6) [Figure 20-31-1] 27000 kPa (270 bar) (3916 psi)
Base End (Item 7) [Figure 20-31-1] 27000 kPa (270 bar) (3916 psi)
Bucket Port Relief set at:
Rod End (Item 8) [Figure 20-31-1] 27000 kPa (270 bar) (3916 psi)
Base End (Item 9) [Figure 20-31-1] 27000 kPa (270 bar) (3916 psi)
Install the hand pump hose and a 34474 kPa (345 bar) (5000 psi) pressure gauge into the valve section work port in which the port relief valve is located [Figure 20-31-2].
NOTE: The valve is shown removed from the excavator for photo clarity.
Slowly pressurize this section with the hand pump until the port relief valve opens and make a note of the pressure reading.
If the port relief pressure setting needs to be adjusted, release the hand pump pressure valve.
Loosen the lock nut (Item 1) [Figure 20-31-2] and [Figure 20-31-3].
Turn the adjusting screw (Item 2) [Figure 20-31-3] clockwise to increase the pressure and counterclockwise to reduce the pressure.
