57 l/min tractor hydraulic tests - High flow rate system


The open centre hydraulic system comprises two systems: the low flow rate system and the high flow rate system.
Before starting the tests, run the engine at 2000 rpm to raise the oil temperature to 60 °C (132 °F) minimum. To make the rise in temperature easier, connect a flowmeter to one of the auxiliary spool valves other than the one supplied by the flow divider (if fitted) and limit the flow through the flowmeter. As soon as the oil temperature reaches or exceeds 60°C (132°F), release the lever of the auxiliary spool valve and open the flowmeter load valve to the maximum.

High flow rate system

Safety valve test
- Connect a pressure gauge with a coupler ref. 3582045M1 to the diagnostics connector (1).


This diagnostics connector is located:
- either on the trailer brake valve (if fitted);
- or on the cover plate (2) fitted to the right-hand hydraulic cover plate.
- Run the engine at 2200 rpm.
- Activate an auxiliary spool valve to open the valve.
- Check P1 = 195 ± 5 bar.
If pressure P1 is not correct, adjust the safety valve using shim(s).
- At 1000 rpm, the pressure should not drop.

Checking the flow rate of the pump 
- Connect a flowmeter to the quick coupling of an auxiliary spool valve other than the one supplied by the flow divider. Connect the return directly to the housing via the transmission filler port.
- Connect a suitable pressure gauge to the diagnostics connector (1). Check that the flowmeter load valve is open fully.


- Activate the spool valve.
- Adjust the flowmeter load valve to obtain P1. Do not consider the value of the pressure gauge fitted to the flowmeter. Look at the separate pressure gauge connected to the diagnostics connector (1).
- Check Q1.


Checking the flow divider (if fitted)
- Connect a flowmeter to a quick coupling on auxiliary spool valve no.1 located by the flow divider "D"


Connect the return directly to the housing via the transmission filler port.
- Connect a suitable pressure gauge to the diagnostics connector (1). Check that the flowmeter load valve is open fully.
- Activate the spool valve.
- Adjust the flowmeter load valve to obtain P1.
- Check the flow rate of the divider by turning the adjusting knob shown.
- Check Q2.

Engine speed (rpm) - 2200
P1 (bar) - 0 to 150
Q2 (l/min) - 0 to 53
Do not consider the value of the pressure gauge fitted to the flowmeter. Look at the separate pressure gauge connected to the diagnostics connector (1).

Checking Kick-out pressure on an auxiliary spool valve fitted with automatic return to neutral
- Connect a flowmeter to the relevant spool valve.


- Connect a suitable pressure gauge to the diagnostics connector (1).
- Run the engine at 2200 rpm.
- Activate the spool valve in automatic return position.
Release the lever and gradually shut the flowmeter load valve until the lever returns to neutral position.
- Check the Kick-out pressure: P1 = 150 - 170 bar.
Make sure that the spool valve is in the automatic return position and not in the floating position. Do not consider the value of the pressure gauge fitted to the flowmeter. Look at the separate pressure gauge connected to the connector (1).

Checking the pressure and flow rate of the trailer brake
Pressure
- Connect a pressure gauge to the trailer brake connector (1).
- Run the engine at 2200 rpm.
- Lock the brake pedals together and apply a progressive force.


The pressure read should increase gradually until it reaches P2 = 130 - 150 bar maximum.
Flow rate
- Connect a flowmeter to the trailer brake connector (1).
Connect the return directly to the housing via the transmission filler port.
- Run the engine at 2200 rpm.
- Activate the coupled brake pedals.
- Check Q6 = 24 - 31 l/min.

Testing the linkage security valve (1) 


- Disconnect the supply hose pipes on the rams and connect them to a manual pump.
- With the engine stopped and the linkage valve in neutral position, inject pressure into the system.
- Check the valve opening pressure: P3 = 200 - 210 bar