Ford 555 steering problem

[agrimax]

Steering working to the right but not always to the left but now it's intermittent both ways. Steering wheel will turn free but not move the rams and then it'll work ok again briefly. Always works ok with the wheels off the ground.
Have resealed and tested both steering rams. No leakage internally or externally. Have blanked both fittings from steering motor to rams and the wheel is solid both ways,which I'd expect eliminates the motor? Haven't got round to pressure testing the pump yet but would expect hard steering rather than a free turning wheel if the pressure was down. Anyone know if a weak relief valve in the pump would cause this problem?
@Bury the Trash ...Remember you were looking at buying a 550 with a similar problem years ago. Perhaps you didn't buy it or if you did,how did you fix it?

 

[Bury the Trash]

No i didn't buy it, not a huge negative i dont think but simply i too much work on at the time to take on any more repairs
if i remember correctly i had it down as a problem with the orbital.

 

[agrimax]

Thanks. I'm leaning towards that myself...

 

[essexpete]

Probably a daft question but is this a 2wd and could it be possible for worn kingpins to be jamming up?

 

[agrimax]

It is 2wd pete.Everything's free to turn on the steering. Changed the relief valve too but it made no difference. Have decided something has gone wonky in the orbital unit. Must be oil bypassing in it somewhere...intermittently.
Looks a lovely job to remove and replace...not!

 

[essexpete]

Like not exactly appropriate.