jcb ROBOT 150, Service Manual

Page: 174 / 254

10 - 11
Hydrostatic Pump
from machine no. 676355
Pump Neutral Adjustment
This procedure may be carried out if the machine creeps
when the drive joystick is in the neutral position. This fault
may be due to an incorrect neutral setting of the servo piston.
1
Identify which pump section requires adjustment.
If the machine veers to the left this could be caused by
either the right hand wheels moving forward or the left
hand wheels moving in reverse. Remember that pump
P1 drives the right hand motor and pump P2 drives the
left hand motor.
If the machine moves either straight ahead or behind
then both pump servos must be adjusted equally.
2 Stop the engine.
3 Remove the floor plates.
4 Loosen locknut A and turn the ‘neutral’ adjusting screw B
1/10 of a turn in the required direction then re-tighten the
locknut.
If the wheels are creeping forward, turn the adjusting
screw in a clockwise direction (looking underneath the
pump). If the wheels are creeping in reverse, turn the
screw anti-clockwise.
Note: This adjustment is very sensitive . Turn the adjusting
screw 1/10 of a turn at a time and re-check. A slight
movement when the wheels are raised is acceptable
provided that no movement occurs when the machine is
resting on the ground.
5 Start the engine and check that the wheels are
stationary.
6 Finally tighten locknut A to 23 Nm (17 lbf ft), taking care
to retain the set position of adjusting screw B .
7 Re-check for wheel movement.
Section E
Hydraulics
9803/8500
Section E
*10 - 11
Issue 2*
Pumps
S244940
A
B
P1
P2
*