308C CR Excavator Hydraulic System – Pump Control (Output Flow) – Adjust

Adjust the pump output flow if the flow test results differ greatly from the specifications.




Illustration 1 g00858716

Pump compartment

(39) Locknut

(40) Setscrew



Illustration 2 g00394882

Pump regulator

(39) Locknut

(40) Setscrew

(41) Shim

  1. Loosen locknut (39) .
  1. Turn setscrew (40) until output flow is adjusted to the correct specification. Turn setscrew (40) clockwise in order to increase the output flow of the pump. Turn setscrew (40) counterclockwise in order to decrease the output flow of the pump. A 1/4 turn of setscrew (40) will change the output flow of the pump at the following pressures.
    1. The output flow of the pump will change approximately 3.4 L/min (0.9 US gpm) at a system pressure of 13700 kPa (1975 psi) when the constant horsepower flow control is active in the first stage of the hydraulic horsepower curve.
    1. The output flow of the pump will change approximately 2.6 L/min (0.7 US gpm) at a system pressure of 31400 kPa (4550 psi) when the constant horsepower flow control is active in the second stage of the hydraulic horsepower curve.
  1. Use shim (41) in order to adjust the output flow of the pump along the hydraulic horsepower curve. Changing the thickness of the shim will change the output flow of the pump in the following manner.
    1. A change in the thickness of the shim of 0.1 mm (0.004 inch) will change the flow rate approximately 0.54 L/min (0.14 US gpm) at the first stage of the hydraulic horsepower curve.
    1. A change in the thickness of the shim of 0.1 mm (0.004 inch) will change the flow rate approximately 0.1 L/min (0.03 US gpm) at the second stage of the hydraulic horsepower curve.
  1. Tighten locknut (39) to a torque of 240 ± 20 N·m (175 ± 14 lb ft).