JCB JZ70 tracking issues

[honey_badger]

Hi all -
I've got a JCB JZ70 and the two speed tracking isn't working. The tracking button on the floor is working alright, it's changing the speed displayed on the digital display, but whether there is a Hare or Tortoise displayed on the monitor, the tracking is always on the slower of the two speeds.
Looking through the fault finding section on the workshop manual these are the possible faults listed after 'Does not change from low speed to high speed':

A) - Faulty operation of high pressure selection check valve
B) - Faulty operation of switching valve
C) - Low pilot pressure
D) - Faulty operation of 2-speed switching piston

Can anyone shine any light on where might be the place to start/what to check first? And whereabouts in the machine it is located?

Thanks all.

 

[V8Druid]

Hi all -
I've got a JCB JZ70 and the two speed tracking isn't working. The tracking button on the floor is working alright, it's changing the speed displayed on the digital display, but whether there is a Hare or Tortoise displayed on the monitor, the tracking is always on the slower of the two speeds.
Looking through the fault finding section on the workshop manual these are the possible faults listed after 'Does not change from low speed to high speed':

A) - Faulty operation of high pressure selection check valve
B) - Faulty operation of switching valve
C) - Low pilot pressure
D) - Faulty operation of 2-speed switching piston

Can anyone shine any light on where might be the place to start/what to check first? And whereabouts in the machine it is located?

Thanks all.

dead solenoid on the valve - or a relay if there's one that operates it?

 

[honey_badger]

dead solenoid on the valve - or a relay if there's one that operates it?

yes solenoid was what I was thinking. Any idea where the valve might be located or ought I just study the workshop book properly to find it?

 

[V8Druid]

yes solenoid was what I was thinking. Any idea where the valve might be located or ought I just study the workshop book properly to find it?

'Fraid i can't help you ..... never seen one ...... Aiden'll know though, I'd have thought ... @CPS

 

[honey_badger]

'Fraid i can't help you ..... never seen one ...... Aiden'll know though, I'd have thought ... @CPS

That'd be great, thanks. I'll send him a message.

 

[CPS]

That'd be great, thanks. I'll send him a message.

Just seen your message, il have a look for a manual over the weekend