jd 155r steering went hard

[paul&mandy]

Hi, just been carting, coming down the road the steering went hard almost impossible to control it. limped it back carefully and turned it off for 5 mins and all is fine, just did another load before the rain and all is fine
Any ideas why it done that?

 

[Mouser]

Dirt in backend oil gets stuck in steering valve. Unbelievable in this day and age but apparently a well known fault with jd since the 20 series at least.
A direct drive one at work had gearbox work done and when came back was like this. Dealer has home made contraption for pumping oil out spools through a series of filters and back in clean. Done 3/4 times over a week to cure it.

 

[paul&mandy]

Dirt in backend oil gets stuck in steering valve. Unbelievable in this day and age but apparently a well known fault with jd since the 20 series at least.
A direct drive one at work had gearbox work done and when came back was like this. Dealer has home made contraption for pumping oil out spools through a series of filters and back in clean. Done 3/4 times over a week to cure it.

Not long had the filters changed, im very fussy with keeping fittings clean etc. Bit scary loosing steering on a bend on the road....

 

[Flat 10]

If you touch the brake will it come back? One I know has similar problems to that and dabbing the brake cures it..
An older model but I think that the brake and steering circuits should all have priority....
@Phil P will know more...

 

[Phil P]

If you touch the brake will it come back? One I know has similar problems to that and dabbing the brake cures it..
An older model but I think that the brake and steering circuits should all have priority....
@Phil P will know more...

I’d have to check the hydraulic diagram as I’m not 100% sure what’s changed between a 30 and an R.
However I’d need a little more detailed to try and narrow it down, where all the other hydraulic functions still work ok? Brakes scv’s etc. Did the steering go any easier when the brakes are pressed or a scv operated?

In reality it can only be one of 3 things, the pump, the priority valve or the steering orbital. Only trouble is it’s very hard to diagnose unless it’s an active fault!

 

[paul&mandy]

I’d have to check the hydraulic diagram as I’m not 100% sure what’s changed between a 30 and an R.
However I’d need a little more detailed to try and narrow it down, where all the other hydraulic functions still work ok? Brakes scv’s etc. Did the steering go any easier when the brakes are pressed or a scv operated?

In reality it can only be one of 3 things, the pump, the priority valve or the steering orbital. Only trouble is it’s very hard to diagnose unless it’s an active fault!

When i pressed the brakes the steering come back fine, soon as i released the brakes the steering went hard again.
The scvs all worked fine.
We got going again chopping and it was on a trailer and done this afternoon without a problem.

 

[Phil P]

When i pressed the brakes the steering come back fine, soon as i released the brakes the steering went hard again.
The scvs all worked fine.
We got going again chopping and it was on a trailer and done this afternoon without a problem.

I’ll have to double check but if it’s still the same setup as a 30 series that will rule out the priority valve as steering and brakes are both on priority 1. I would say the steering load sense check valve is sticking on its seat, still don’t rule out the orbital but it’s rare they fail unless the oil is countermined.