HYDRAULICS 1.63 Adjusting the pump The main system pressure and the standby pressure can be adjusted using the adjusters (19 and 20) on the LS compensator valve (1). The procedure for adjusting the hydraulic pressure is as follows: NOTE: Only check hydraulic pressure when oil is at normal working temperature (60 ± 4°C) and with engine at fast idle (1800 rpm). Main system pressure Connect pressure gauge to test point 1 (65). Start engine. This gauge will indicate the load sensing signal required by any of the services being operated.
Operate any service and read the pressure requirement, when a service is operated to its limit the maximum pressure of 250 bar (3625 psi) will be maintained and the pump will ‘de- swash’. Read pressure gauge. Adjust pressure spring (21) using adjuster screw (20) to set the pressure to 250 ± 5 bar (3625 ± 70 psi) Standby pressure Connect pressure gauge to test point 5 (69) . Start engine. Make sure all services are in neutral then read the pressure gauge. The pressure should be 20 bar (290 psi). Adjust pressure spring (17) using adjuster screw (19) to set the standby pressure to 20 bar (290 psi). 1. LS compensator (3) 3. Volumetric flow controller 17. Pressure spring (standby pressure) 19.
Adjuster screw (standby pressure) 20. Adjuster screw (main pressure) 21. Pressure spring (main pressure) AA Supply oil BB Oil at reduced pressure DD Control oil LL Tank