Jd400 power steering failure

[Orjd400]

Jd400 recently put in new seal kit in the steering wheel body because it was leaking at the top and it was working good, no issues other than chasing leaks, first in the nylon return line then side cover with the bushing below steering wheel.

Yesterday the left tire went up slight incline and cocked hard left and I lost 99% steering.

Looking for opinions, I think i blew a seal in the steering wheel body when the tire went hard left and the pressure was too much for the seals.



Update: Shaft broke off 2" above the pin. Not sure if I could weld it back together or if I need find new assembly.

 

[Tx Jim]

I suppose opposite ear is intact. I think successfully welding ear back in place will require removal of shaft(part # T36482). There is very limited space to "V" then weld area of ear furthest from view. I think tractor salvage yards would have a more than ample supply of the used shafts.

 

[Orjd400]

I found the replacement part. Thankfully I won't need to try repair it.

 

[Tx Jim]

Congratulations & thanks for updating your thread

 

[Orjd400]

Here's the finished repair. Ended up breaking the pin pressing it out so I had to turn a new one. The pin is 1.75 x .621.

 

[Tx Jim]

Are you replacing the 6 large o-rings that fit in seperate grooves in steering valve housing?

 

[Orjd400]

Are you replacing the 6 large o-rings that fit in seperate grooves in steering valve housing?

I replaced those seals a few months ago. Do you know if its normal for the wheels to turn without steering input? (Example) one wheels goes over a rock and causes wheels to turn max steering angle. I think that's what contributed to the shaft breaking.

 

[Tx Jim]

Frt wheels aren't supposed change angle without moving steering wheel. Steering on 400 is mechanical with hyd assistance.

 

[jonsstihl]

in the offroading world of lifted 4X4's they call that bump steer. But I'm sorry I don't know much about it and how to solve it but it seems to have something to do with linkages and angles that are changed when lifting a vehicle. maybe something in the steering linkage got put back in upside down after the rebuild.

 

[rScotty]

Frt wheels aren't supposed change angle without moving steering wheel. Steering on 400 is mechanical with hyd assistance.

Hydraulic assist grafted by the factory onto manual steering was popular back in the 60s and 70s - but had lots of problems. Operators needed to be careful about over-stressing it. Basically the designers should have bulked up the entire steering linkage to handle hydraulic forces, but didn't. Deadheading and the leaks that caused were common. Then before the hydraulic/manual technology had a chance to mature, along came better hydrostatic steering and simply ran away with the game.

Not saying what your problem was caused by, but consider that crack may have been there from ages ago and your bringing the system up to specs was the last straw.

But you could certainly rebuild one and use it reasonably and expect it to last. Just don't be trying to scoot rocks to the side with the front tires...& stuff like that.

rScotty