JCB 540 seeking info

[Madcapmagician]

Hi there I'm working with a 2003 model JCB 540-70 telehandler. It's a good machine but it is missing the operators manual. Does anyone know a reliable source other than the dealership? I have the service manual.. go figure.. failing a manual, can anyone give me the re-phasing instructions for the steering? I've just finished adjusting the sensors and it is pretty good but it still never feels like it's going in a straight line.

 

[jcb jeff]

Should just put into 2ws mode and turn steering full left and right and that should phase the steering.
How it works is the front switch operates the rear and rear the fronts when it comes to locking out the steering between modes so if you go to two wheel steer and this should lock out the rear wheels once the switch is aligned depends on air gap between the washer and bottom of the blue sensor. so get the back wheels straight and the same with front by adjusting the brackets slightly until you feel its straight .
The main cause of switch failures are external force to the switch damaging the blue part of the sensor or the wiring damaged in the plug normal to rip the wires out .
There is a relay box / relay ecu i think its under the seat box on some models and under the dash on others .
If you find whilst traveling in 2ws and the back wheels keep coming out of line suspect ram seals allowing oil to bypass on some pre 530/70 the anti cavitation valve would play up and introduce air to the steering circuit causing the rear to wander .
It always seems as its the rear wheels to go out of align but you are always correcting the steering and wanting to point the front wheels straight so always have a good look first.

 

[Madcapmagician]

Thanks for the info jcb Jeff. The machine is in the workshop right now having the front steering ram resealed as it was leaking. None of the sensor wires are damaged thankfully. The machine was working for quite a few years with no rear sensor. When we acquired the machine we fixed that straight away but ever since then it always feels like the back end wants to pass the front down the right hand side. We use it in 4WS mode 99% of the time on a paved flat site so it really doesn't get to travel far. When we do however, it is a bit freaky to see a big machine driving in a straight line but sort of offset to the left. Soon as it comes back I'll try your suggestions. Thanks again.

 

[jcb jeff]

They say you should go through the 4ws into 2ws at least once a day to re phase the alignment but like I said you only ever think its the back as most of the time you drive up the road try to keep the fronts pointing straight .
They say you should road the machine in 2ws only but who does but might be a good test to drive it about up and down the road and see if the back creeps out of line.