9540 steering problem

9540 with 5000 hours has a problem with power steering. It occasionally locks when turning left or right. Turning slightly the opposite direction immediately clears blockage, or you can force the wheel round if in a field and not panicking.
Have changed the oil and filter with no improvement, any help appreciated.

Hi Zed, i never had a 9540, but we had a 12145 at home and the ram on the front axle for the steering would only stay working for about 3 months at a time before needing new seals. and when they were about to go the steering would be just like you describe.the problem a previous driver have managed to sprain the chrome part of the ram and was ruining every set of seals.

if its the other style steering system with the big lump under the rad, there's a lot of ball bearing in the distributor.could be a place to look.

Hi,

Check the front hub swivel bearings.

Mike

Check the front hub swivel bearings.

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indeed sounds like a jamming bearing... This size of bearing only breaks down due to moisture and rust because the very same size kingpin wheel bearing is used in the UR2, i drilled a grease zerk to it on our 5245 so i can push dirt and moist out with new grease.

Thanks for the advice folks.
Re grease, did you drill the hole with out dismantling the hub, a I know from experience with UR2 this is a heavy job.

a badly pitted, jamming bearing doesnt revive with grease....

No i drilled it horizontally into the side of the plate that bolts under the mudguard support, which has the shaft end to it on which the bearing mounts.

Removing the bearing isnt that much of a job if you know the trick: Its a bitch if you try with a bearing puller, but if you weld a piece of steel in the bearing race and pry on it, its easy: When they are heated the steel becomes plastic, when it cools again while being compressed (due to being pressed in the housing) the clamping force is mostly gone. It also works on the inner race on the shaft end, though i mostly grind them away untill the surface of the shaft end to relieve the pressfit pressure.

Do not think bearing can be pitted as I had tractor from new and it is housed 95% of the time. Will look at the plate you mention an see if I am brave enough to drill it in situ. Thanks.

i drilled perpendicular to get around the mudguard mounting plate underneath, and when the mudgiard mounting plate was removed i drilled through the center of the shaft end to get the grease to the top of the bearing chamber, then tapped and plugged the end of the grease channel with an M8 bolt, then cut it flush and remounted the mudguard mounting plate.


Anyways i would expect the problem in the orbitrol to be honest...

Those plates have grease nipples from new on the 9540.
Steering is sticking in same place each time, just right of straight, even though the steering wheel may be in a different position. Would this indicate it is an axle problem, not the orbital?