Steering box gears (1 Viewer)

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Joined
Aug 15, 2019
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Location
New Zealand
Has any had any luck filing or grinding the teeth on the sector shaft and/or power piston teeth to make gears mesh smoothly and take any play out? Especially removing any burs or ridges which can cause binding.

I have a few spare boxes and they all have play where the teeth mesh, but bind if the adjuster screw is done up to remove this play (specifically when not centered)

I’m certain this is what 99% of people’s steering play problems are in these types of steering boxes

I’m going to experiment with some files and a angle grinder with sandpaper disc.

It seems the sector shaft has a variable slope, but the power piston has straight edges on the teeth.

Any advise from anyone that’s had a go at this?

Cheers
 
Our shop has resealed/rebuilt a couple dozen of these boxes and we have never really had any binding from tooth interference. That includes upgrading several 80 series boxes with the 105 sector shaft.
 
I’m going to experiment with some files and a angle grinder with sandpaper disc.

That sounds like a really bad idea. They're probably hardened surfaces, too, so if you manage to cut into them they'll subsequently wear out quickly.

After rebuilding my steering gear, I adjusted the screw *while moving the steering column shaft back and forth* using Vise Grips near the steering gear input shaft. Tightening it to the point that I just barely felt binding at the steering wheel (front wheels off the ground, ignition in the on position, engine not running) at the center resulted in much better steering.
 
Then how to you get it meshing flush with wear and burs on the teeth that causes the binding?
 
Then how to you get it meshing flush with wear and burs on the teeth that causes the binding?

Why do you have burrs on the teeth? Mine didn't at something like 260k miles, and that was with abuse from the previous owner running with a badly leaking pump and gear.

Also, what do you mean by meshing flush?

As for binding, the teeth are designed so that they mesh more tightly near the mid-point. When I say binding, I'm referring to *very slight* binding felt at the center point with no power steering assistance.
 
Because it was wearing in a certain part of the teeth, between that wear and the original/untouched surface there is a lip or bur. Run your fingernail over the teeth and you'll see what I mean. All 3 spare boxes I had have this.

When you add a new sector shaft to a worn power piston the metal surface in the teeth doesn't contact each other the same as it did with the original sector shaft (it wears together).

Also refer to Parts for steering box rebuild - https://forum.ih8mud.com/threads/parts-for-steering-box-rebuild.1254109/post-13890553 which might help explain what I'm talking about.

No amount of tightening the adjuster screw will help unless both sector shaft, and the power piston teeth are smooth and contact each other well. Only then can you tighten the adjuster screw to set the preload WITHOUT any binding.

I've already started experimenting and having good results, much smoother now and I can tighten down the adjuster a little more now that it doesn't bind therefore creating a much tighter steering feel.

Obviously my method is not as good as a machine shop lathes and I'm not sure I'm getting the gradient quite right of the taper - but I'm seeing results.
I'm using an angle grinder with sandpaper disc, then some really fine wet hand sanding, then some emery cloth. I'm reassembling with some wheel bearing grease in the teeth. Perfectly smooth.

Surely someone has given this a go ?
 
I love the enthusiasm to bring parts back into service.

However, this isn't a grinder-suited job if you want the box to function properly when reassembled. Those teeth are hobbed to a very specific shape to maintain tight steering throughout steering travel. Sometimes parts are too far gone to fix in the shop, and new ones need to come into the fold. For as-new steering, the box will need parts that fit together truly as-new. Anything is a balance of compromises.
 
I love the enthusiasm to bring parts back into service.

However, this isn't a grinder-suited job if you want the box to function properly when reassembled. Those teeth are hobbed to a very specific shape to maintain tight steering throughout steering travel. Sometimes parts are too far gone to fix in the shop, and new ones need to come into the fold. For as-new steering, the box will need parts that fit together truly as-new. Anything is a balance of compromises.
That is what I was worried about. Thank you for that.
Unfortunately Toyota discontinued the power piston/valve assembly so buying that part new isn't an option anymore.
 
Like stated in post #7 the piston teeth are rack cut while the involute sector teeth are hobbed. Both are cut with a small incline so they can be run at zero lash.

Gears are surprisingly complex.



That's a good video explaining what it takes to grind a spur or helical gear. Pay attention around the 1:35 mark in the video as it shows exactly how the grinding wheel generates the involute shape of the gear tooth.

Pfauter and Liebherr are kind of the leaders in gearmaking. Pfauter invented hobbing.
 
Like stated in post #7 the piston teeth are rack cut while the involute sector teeth are hobbed. Both are cut with a small incline so they can be run at zero lash.

Gears are surprisingly complex.



That's a good video explaining what it takes to grind a spur or helical gear. Pay attention around the 1:35 mark in the video as it shows exactly how the grinding wheel generates the involute shape of the gear tooth.

Pfauter and Liebherr are kind of the leaders in gearmaking. Pfauter invented hobbing.

I need a cigarette
 

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