Western model R's, steering assist knuckle

[Full Floater]

On the western model R's.  They seem to have this steering assist cylinder, coupled to the frame with the specific U joint.   

I have 3 of them, all with a fair bit of wear.  Mack has discontinued this part.

What are our options for replacement or re and re?

 

Thanks

[Full Floater]

How about deleting the steering assist cylinder?

[mowerman]

I had a Mack western I don’t remember that thing

[Geoff Weeks]

1 hour ago, mowerman said:

I had a Mack western I don’t remember that thing

Likely a heavy front axle, that looks like the passenger side from the photo.

[Vladislav]

My guess the truck has valve assembly in the drag link and the power cylinder at the right. Doesn't it?

[Geoff Weeks]

Could be Vlad, I just haven't seen it done that way.  I was thinking an assist cyl on the right and a power on the left so the tie rod doesn't take the full force.

[Full Floater]

Yes, it's the passenger side.   I have 3 westerns that range from 12k to 20k front axles and they all have them.  The Easterns don't seem to have them.

Edited November 5 by Full Floater

[The Heinz]

It's really common around here for newer cement mixers and heavy dump trucks to have a second steering gear on the passenger side, but the setup is very different from this.  

[Vladislav]

Easterns usually had integrated steering boxes. That Western setup we talk about was born as an upgrate of mechanical steering. Mechanical gear in its place at the left rail with drag link attached to a Pitman arm. But the link has a valve assembly incorporated in it so when you apply force to it by steering wheel one or another valve opens (depending on the direction) and supplys pressure to a power cylinder which is fitted in parallel to the drag link. It may be fitted at the other side of the chassis (at the right) or right near the drag link.

As soon as the cylinder has made his job moving the wheels the valve closes. If you continue forceing it by your hands cylinder continues turning the wheels further more.

Actually this setup can be hydraulic or air and power cylinder can be attached to a tie rod too since there's no matter which point of the steering system you move. And may be arranged as an add on kit.

[Vladislav]

On 11/4/2024 at 10:32 PM, Geoff Weeks said:

Likely a heavy front axle, that looks like the passenger side from the photo.

I don't know is that an assist cylinder or the only power cylinder. Which I would also call a power assist cylinder. Just depending on what it assists to - to the main cylinder or to a steering system.

[Full Floater]

Yes there is a conventional steering gear box and pitman arm/drag link on the left (drivers) side.   Fluid also leaves the steering box to this assist cylinder on the passenger side.  Which leads me to believe that it cannot be deleted as those ports in the steering box still must flow fluid somewhere

[Mark T]

Might have to retro a different assist cylinder on there. Most I've seen use some form of ball and socket joint.....like on Western Stars. 

[Vladislav]

16 hours ago, Full Floater said:

Yes there is a conventional steering gear box and pitman arm/drag link on the left (drivers) side.   Fluid also leaves the steering box to this assist cylinder on the passenger side.  Which leads me to believe that it cannot be deleted as those ports in the steering box still must flow fluid somewhere

Sounds like the valves are in the steering box with power cylinder put separately. You can only remove the lines from everywhere including steering pump and get a mechanical steering. What is I guess way far from what you want.

The joint can be repaired in a machine shop. But that would be a headach and the truck must be parked for that time.

[Geoff Weeks]

On 11/5/2024 at 3:08 PM, Full Floater said:

Yes there is a conventional steering gear box and pitman arm/drag link on the left (drivers) side.   Fluid also leaves the steering box to this assist cylinder on the passenger side.  Which leads me to believe that it cannot be deleted as those ports in the steering box still must flow fluid somewhere

Picture of the box would help, but if it is like I am thinking, you can delete the cylinder and hose at the box (plug) and it will work. However they are most often used on heavy front axles so the tie rod only has to keep both wheel ends in sync and not transmit the force. When you cut back to just the steering box moving the wheels, the tie rod has to transmit all the force to the passenger side and you can end up bending the tie rod. You would also have less assist if the box is doing it all.

 I wouldn't recommend deleting the assist on the passenger side, and would only do so to move around the shop or for a hobby truck that isn't loaded.

 Some of the early P/S boxes were "low pressure" boxes and run much less pressure and therefore power, so may be that is why an assist cyl is needed. 

 Early Sheppard boxes were low pressure boxes, and the assist hoses on the Sheppard box goes to the bottom (opposite the input shaft), and the other to the top-side of the bolt down cap on the input side if the box.

 Again, pictures and/or steering box model numbers would be of help.

Edited November 7 by Geoff Weeks

[Full Floater]

Well I as able to install 2 shims, 7/8" ID, 1 in either direction of movement in this joint.  And that has taken up a majority of the slop.  I am happy with the turnout.   I would consider this a decent at home fix without having to have anything machined.