The Classic Machinery Network

have 2 problems with my old jcb 3cmk3 powertrain when rear end is in a hole with front higher the hydraulics only work slow or not at all but its ok on level ground or with back higher than front looks like not getting oil to the pump? what does anyone think it could be can leave bucket in the air all night no movement
the other problem i have is the steering sometimes wont work it takes a while to turn any ideas please

I know it sounds stupid but is it low on hydraulic oil ? I would start there first maybe give it a hydraulic fluid and filter change also clean the strainer out too, With the steering quite often on 3cmk2 and mk3 machines it could be the orbital steering valve its a common fault, They quite often leak. Simon Vicary will probably have parts to fix the problems for you.

Definitely check oil level. Huge capacity and if really low will require quite a lot. Sounds like the pick up is coming out of the oil with the rear down.

topkit wrote:I know it sounds stupid but is it low on hydraulic oil ? I would start there first maybe give it a hydraulic fluid and filter change also clean the strainer out too, With the steering quite often on 3cmk2 and mk3 machines it could be the orbital steering valve its a common fault, They quite often leak. Simon Vicary will probably have parts to fix the problems for you.

thanks for all the advice how do i get to the orbital steering valve any pictures anywhere theres none in the manual

Its the hydraulic control the steering wheel attaches directly to. If you remove the covers, you can see the pipework leading to it.
When my hydraulic oil is really low, I have difficulty getting the steering to respond, and I add oil and it cures itself.
So perhaps it might be a idea to verify the hydraulic oil levels are where they should be before tearing into it.

thanks will try anything had loads of problems in passed trying to work through them but taking ages

Hi,
Just a thought.
If the oil level, filter and suction strainer are OK it might be worth checking the suction hose which feeds the pump.
I have known these collapse internally and restrict the oil supply.
Layers in the hose can de-laminate and close, block, the pipe internally cutting off the oil supply. The pipe can still look OK externally.

Fred

thanks is the suction strainer the one under the thick plate near the step ,
the rubber hose that feeds the pump will any hose the same diameter work

are jcb 3cmk 3 steering valves easy to repair or do i look for a s/h one thanks