1 Ton Rack and Pinion Steering on a SFA rig...

[Deuling]

I was under the impression that for full hydro you need an orbital valve instead of the stock steering box.

But it works for hydro assist so......

Is it just not enough to supply the power that it takes to run full hydro?? Idk. I need to take some hydraulic classes at school

 

[Stomis]

I was under the impression that for full hydro you need an orbital valve instead of the stock steering box.

But it works for hydro assist so......

Is it just not enough to supply the power that it takes to run full hydro?? Idk. I need to take some hydraulic classes at school

For some reason my brain is tickling about the thought that a standard steering box wont work as an orbital without feedback from the mechanical linkage.

 

[Deuling]

The geometry on the sketch looks like it will bind. And if you have a foot of travel, the middle of the shaft will need at least 6" of clearance.

That was why I would make the yellow/orange colored shaft have a huge slip joint like on a front drive shaft, that could go up and down.

 

[Deuling]

For some reason my brain is tickling about the thought that a standard steering box wont work as an orbital without feedback from the mechanical linkage.

Theres gotta be a reason nobody does it

 

[Stomis]

That was why I would make the yellow/orange colored shaft have a huge slip joint like on a front drive shaft, that could go up and down.

Could also rig up a double cardan, heim support and then another double to get the angle into check pre slip.


I think the thoughts on this are better directed towards figuring out how to hook up an orbital in tandem with a steering box. But its still gonna have the bumper steer on the street driving there.

 

[Deuling]

I think the bump steer on the street would be so minimal it would never be noticed.

When your jumping it though and smashing and extending the suspension to its limits, I feel like thats when I would be the most noticed.

 

[ktmoutfront]

Slow down. I can't keep up.

Full hydro needs a matched orbital valve. For what he wants, a solid link tied system is needed.

A crossover 4 link system should have the engine moved back so the links have room to travel.

 

[Stomis]

I think the bump steer on the street would be so minimal it would never be noticed.

When your jumping it though and smashing and extending the suspension to its limits, I feel like thats when I would be the most noticed.

But isnt the steering wheel honestly going nuts during landings and **** regardless of geometry flaws?

 

[Deuling]

But isnt the steering wheel honestly going nuts during landings and **** regardless of geometry flaws?

I dont know. Never jumped a rig that big before

 

[ktmoutfront]

But isnt the steering wheel honestly going nuts during landings and **** regardless of geometry flaws?

No. I rarely have to correct in a landing. If you go into it sraight, no big deal. The faster you are going, the less correction. If it was on pavement, it might be an issue. But I have not jumped on pavement. My nadds aren't big enough.

 

[Stomis]

I dont know. Never jumped a rig that big before

You should talk him into doing custom TTB up front. Thats jump pimp right there.

 

[Deuling]

You should talk him into doing custom TTB up front. Thats jump pimp right there.

I dont know what this is


Fock. Ill be back in the AM. I gotta be to work in 6 hours

 

[Fordum]

I was not going to jump into this, because I have not looked at enough rack and pinion trucks to visualize what is what.

However, let me drop these two ideas in.

I saw a PTO winch on a truck that had the PTO unit on the passenger side of the TC, and the input to the winch on the driver side of the truck.

The PTO shaft went from the TC, forward, then across the bottom of the truck, then forward again to the winch.

And it worked!

If that can be made to work with multiple pillow blocks and U-Joints, under that much load, then you should be able to route a simple low load steering shaft......

My other idea is wilder, and related to going from full hydro to hydro assist and back.

Why does a steering box output shaft have to move???

When you turn the wheel, the shaft tries to move. If it can't, the spring gives, which causes the spool valve to shift and applies the hydraulic pressure.

If you have hydro assist, the drag link is resisted and it causes pressure to both the ram and the internals.

What if you removed the drag link and locked the output shaft for off road?

The wheel would not turn beyond a certain point, but the truck would.
It would be like the modern fighter jets. The control stick does not move, but the sensors feel the pressure of the pilot's arm and move the control surfaces accordingly.

It might take some getting use do, but would be way cool to drive........

Then, when you got to the highway, just remove whatever you have attached to the output shaft and reattach the drag link....

 

[ktmoutfront]

Go long travel 4wd A-arm up front if money is no object. I designed one for a guy in Ca. Gave him the price to build it. Then he had a heart attack. Not because of the price. He had a bad ticker. So it never got built.

 

[Stomis]

I was not going to jump into this, because I have not looked at enough rack and pinion trucks to visualize what is what.

However, let me drop these two ideas in.

I saw a PTO winch on a truck that had the PTO unit on the passenger side of the TC, and the input to the winch on the driver side of the truck.

The PTO shaft went from the TC, forward, then across the bottom of the truck, then forward again to the winch.

And it worked!

If that can be made to work with multiple pillow blocks and U-Joints, under that much load, then you should be able to route a simple low load steering shaft......

My other idea is wilder, and related to going from full hydro to hydro assist and back.

Why does a steering box output shaft have to move???

When you turn the wheel, the shaft tries to move. If it can't, the spring gives, which causes the spool valve to shift and applies the hydraulic pressure.

If you have hydro assist, the drag link is resisted and it causes pressure to both the ram and the internals.

What if you removed the drag link and locked the output shaft for off road?

The wheel would not turn beyond a certain point, but the truck would.
It would be like the modern fighter jets. The control stick does not move, but the sensors feel the pressure of the pilot's arm and move the control surfaces accordingly.

It might take some getting use do, but would be way cool to drive........

Then, when you got to the highway, just remove whatever you have attached to the output shaft and reattach the drag link....

This was half our thoughts but for some reason I wanna say I remember reading that the steering box doesnt properly supply pressure without the input from the drag link/wheels. Therefore when you got offroad and dropped the draglink off the truck wouldnt move the ram do to no input. But I could be wrong.

 

[ktmoutfront]

Don't know the internal working of the stock box. But a guy was wheeling with us with hydro assist. Broke the drag link. It would not steer. I welded the shaft back together to get him out of there.

 

[Stomis]

Long travel coilover TTB

The wider the truck the more travel you have. its 1000x better than A arm IFS because the pivot point is on the opposite frame rail. Gives you mega droop without having to move the motor.

 

[ktmoutfront]

But I've seen trucks roll when hooking a drooped tire. A arm can be built to move back as well as up, to absorb the landings. And we were running the pivots 4 inches from center of the truck. Used a corvette rear diff with reverse cut gears etc......

 

[Fordum]

This was half our thoughts but for some reason I wanna say I remember reading that the steering box doesnt properly supply pressure without the input from the drag link/wheels. Therefore when you got offroad and dropped the draglink off the truck wouldnt move the ram do to no input. But I could be wrong.

Never fooled with hydro assist with rams, but I did do some work with power steering gear boxes.
On the ones I worked on, there is a torsion spring that keeps the spool valve centered.
Until the valve moves, there is no pressure applied.
The spring is "between" the input shaft and the output shaft. When you turn the wheel, if the output shaft moves easily, no pressure.
Its when the shaft cannot move easily that the spring twists, the spool valve moves off center, pressure develops and assists the output shaft to move.

As soon as the output shaft realigns with the input, the spool centers again and the assist stops.
If you keep turning the wheel, the output shaft "chases" the input until they are aligned again.

So, if the drag link was disconnected on a standard box, you would never see any pressure.

But, if it was locked so that it could not move, then you would see pressure with no feedback.
The ram would just continue to move as long as you held pressure against the wheel in either direction.

The torsion spring would tend to recenter the wheel when you eased off the turn.

Still say it would be cool to play with.

 

[Stomis]

But I've seen trucks roll when hooking a drooped tire. A arm can be built to move back as well as up, to absorb the landings. And we were running the pivots 4 inches from center of the truck. Used a corvette rear diff with reverse cut gears etc......

Yeah but the A arms droop too no? I dont understand how hooking a front tire on one of these kinda trucks when drooped is any different than on an A arm IFS truck. They both get the camber change on droop.