630 Steering

[zilla24]

Im working through a complete steering system overhaul on my 630. So far I have removed and re-sealed the pedestal, power steering pump and relief valve.

The pedestal is installed and I'm working through the components. As I'm reassembling I have a question on the steering shaft housing and the required shim thickness. I did a quick read through the PS manual and did not find what I'm looking for, I have the old shim which measured .008". Is there a procedure for checking backlash or method for calculating the shim thickness? I don't necessarily want to trust what was in there incase it was wrong.

Item 32 is the shim I'm refrencing:

 

[Paul_IN]

Use the old shim thickness as the starting point.

Did you install the steering gear at top of the pedestal shaft in the same orientation as removed or did you rotate it on the splines during reassembly to expose unworn teeth? Either way you want to ensure checking lash of worm and gear in the tightest (unworn gear teeth) spot. This might not occur in the straight ahead steering position.

I don’t have the power steering service manual handy to review at present. My model 50 tractor service manual say 1/2 to 1” free play at rim of steering wheel. This was easy to check on manual steering. It’s not so clean on power steering tractors because movement in the steering valve actuating mechanism also gives steering wheel rim free play. I would have thought the factory JD power steering service manual would address this.

Here are my thoughts if the power steering service manual is lacking on directions.

Rather than put all the components back together to check at steering wheel I would ensure very free rotation of the worm shaft back and forth a tiny bit by hand at all points. Only
use your fingers to turn to avoid confusing lash from actuating the mechanism. Adjust shim pack as needed then make the final check with steering wheel.