John Deere 2450 steering unit overhaul?

[Rannsachair]

Probably nothing to lose stripping the steering valve, that is a lot of rubbish going through your hydraulics, could just be some crud behind anti cavitation or in cylinder relief valves, the fine tolerances in a steering valve do not cope well with contamination.

 

[reb78]

Probably nothing to lose stripping the steering valve, that is a lot of rubbish going through your hydraulics, could just be some crud behind anti cavitation or in cylinder relief valves, the fine tolerances in a steering valve do not cope well with contamination.

Thanks for that.

On those relief valves... I don't have the kit to reset them. If I measure depths and count turns etc, will this get me close enough do you think? I don't know how fine the adjustments are.

There is rubbish everywhere in the system from these brakes and I caught them before any serious metal got ground. By the date on the transmission filter it was last changed 16 years ago!!

 

[Rannsachair]

Thanks for that.

On those relief valves... I don't have the kit to reset them. If I measure depths and count turns etc, will this get me close enough do you think? I don't know how fine the adjustments are.

There is rubbish everywhere in the system from these brakes and I caught them before any serious metal got ground. By the date on the transmission filter it was last changed 16 years ago!!

You will likely get them close enough if you just measure or count the turns unscrewing them, if they end up too low they may blow of when steering, so just tighten a little. the anti cavitation valves are just ball bearings and a spacer, I would give the balls a light peen in the housing to ensure they do not leak.

 

[reb78]

You will likely get them close enough if you just measure or count the turns unscrewing them, if they end up too low they may blow of when steering, so just tighten a little. the anti cavitation valves are just ball bearings and a spacer, I would give the balls a light peen in the housing to ensure they do not leak.

Excellent. Thanks!! I will order a seal kit and get on it. I will try and flush the ram and lines at the same time.

 

[reb78]

So. Started taking the valve apart. It's a bit grubby inside but not as bad as I was expecting. That's not to say I won't find more more filth in there as I go though as I haven't started cleaning yet.

Odd thing so far - the spool valve and sleeve were an absolute sod to remove from the body. At their normal resting position it was the whole lot would turn but not easily. Pushing to get it out and it jammed up and wouldn't turn at all. Rightly or wrongly I gently tapped it out from the steering wheel side. When out, it appeared to me that the six flat springs may not be sat as they should have been. Pic below. Is this my problem and they have somehow come dislodged? I don't think I damaged the inner face of the body forcing this out but it's possible as what I think is misalignment of these springs was what I think was causing the spool valve and sleeve to bind.

 

[reb78]

Some pics of the inside. Hard to tell if any damage. The tolerances are so tight I am not sure me not feeling anything with my finger tells us much!

 

[Rannsachair]

So. Started taking the valve apart. It's a bit grubby inside but not as bad as I was expecting. That's not to say I won't find more more filth in there as I go though as I haven't started cleaning yet.

Odd thing so far - the spool valve and sleeve were an absolute sod to remove from the body. At their normal resting position it was the whole lot would turn but not easily. Pushing to get it out and it jammed up and wouldn't turn at all. Rightly or wrongly I gently tapped it out from the steering wheel side. When out, it appeared to me that the six flat springs may not be sat as they should have been. Pic below. Is this my problem and they have somehow come dislodged? I don't think I damaged the inner face of the body forcing this out but it's possible as what I think is misalignment of these springs was what I think was causing the spool valve and sleeve to bind.
View attachment 462935

for assembling and removing the spool and sleeve, best to rotate the parts at the same time to prevent jamming. The centering springs shown have moved best disassemble and reassemble.


Difficult to put the springs in with your fingers best gest some bar the same section as the slot and mill and file out as sketch and use the tool by pushing through the slot, hold the front of the springs in the slot and compress the springs with your fingers as you push the springs into position, using the tool as a guide.

Tool like this, best bending the unslotted end 90 degrees to use as a handle.

Check the housing for galling marks.

 

[Rannsachair]

Some pics of the inside. Hard to tell if any damage. The tolerances are so tight I am not sure me not feeling anything with my finger tells us much!

View attachment 462936View attachment 462937View attachment 462938

If there is any damage the sleeve will feel stiff in the housing, it should rotate without any effort, just do not hold the sleeve in your hand too long or hold it in a rag, so you do not heat it up enough to expand - tolerances are that tight.

 

[reb78]

Thanks for that. If they are centering springs I am guessing they won't be the cause of issues?

I will look more tomorrow and report any other findings. I will give everything a good clean and blow through.

 

[Rannsachair]

Thanks for that. If they are centering springs I am guessing they won't be the cause of issues?

I will look more tomorrow and report any other findings. I will give everything a good clean and blow through.

yes, the springs control the deflection between the spool and sleeve and therefore the opening of the valve for steering, the valve will not assemble unless the centering springs are in their correct position.

 

[reb78]

yes, the springs control the deflection between the spool and sleeve and therefore the opening of the valve for steering, the valve will not assemble unless the centering springs are in their correct position.

Just a thought, but if the springs aren't centering could they be leaving the steering partially open to the left side and explain why the machine wants constant correction to the right?

 

[Rannsachair]

Just a thought, but if the springs aren't centering could they be leaving the steering partially open to the left side and explain why the machine wants constant correction to the right?

If that is happening, first thing to check is that the sleeve and spool are free to rotate.

 

[reb78]

If that is happening, first thing to check is that the sleeve and spool are free to rotate.

Going out now. The seal kit has arrived so will continue carefully dismantling and see if I can find anything odd!

 

[reb78]

The spool will move longitudinally in and out of the sleeve but I cannot rotate it within it at all!

 

[Rannsachair]

The spool will move longitudinally in and out of the sleeve but I cannot rotate it within it at all!

that sounds strange, assume springs are out?
Best slide them apart, just need to push out the gerotor drive pin and hold a rag round the springs, so you do not lose any.

 

[reb78]

Got them apart. There must have been some muck in there as they will rotate now. I don't think this was an o ring that's disintegrated but horrible grime that shouldn't be there.

 

[Rannsachair]

Got them apart. There must have been some muck in there as they will rotate now. I don't think this was an o ring that's disintegrated but horrible grime that shouldn't be there.

View attachment 462991 View attachment 462992

The close tolerances do not like contamination, likely that was your problem, the sleeve not centering, so a clean and new seals and you should be good.

 

[reb78]

I hope so!! Reassembling now!

 

[Rannsachair]

There are a few videos on YouTube showing rebuilding an orbital valve, some units can be mistimed with the gerotor which makes them act as a motor.

 

[Jan-DIY]

Fascinating units.
But a bit complex .

Made some hydrostatic steering kits for small traktors long ago.