4 wheel steering on a deuce?anyone done it?

[Unforgiven]

if money is not an option then two separate rear-steer kits would avoid any articulation problems. The dog bones might allow a small amount of lateral movement between the axles at high articulation.

Since it would have to be pin-locked on the highway to be DOT legal, that would be a viable option. The two rams could be tied together with a proportioning valve to adjust the different radiuseseses.

For serious off road this would be ideal. You could have crab walk or tight radius steering. The bogie axle on the stock suspension might interfere with the front tie rod. But it is a very interesting concept for anyone wanting both a road and an off-road combination vehicle. Offset rims would be needed to clear the rear leaf springs if the stock rear suspension is used.

 

[mudguppy]

... You're absolutely right that it would be possible to use some type of mechanical linkage to connect thew two axles. Just not how I would choose to do it, ...

Jesse,

imagine two front axles configured exactly like they would be in a front configuration, complete with pitman (or 'steering') arms. instead of a drag link connecting the pitman arm to the steering box, you would link the two pitman arms together. this would ensure that the rears stay true to each other.

there will be slight steering differential as the axles articulate, but i think this would be quite minimal, especially when on the road.

then put a steering ram on each axle tie-rod, plumb them as a parrallel circuit, and you're done.

 

[jamesfrom180]

I know I might get really flamed for saying this but don't the lowrider guys have a lot of multiple circuit hydraulics figured out. All of the hoppers have electrical operated valves.

Back to the Hurricane concept you could have each wheel with its own actuator/cylinder. The geometry for more than two axles would mean that variable radii would be needed. But I am envisioning a very sick steer by wire system with unlimited steer axles or even just the wheels themselves. Not unlike the heavy mover already shown here.

I personally am thinking of building a deuce/swamp buddy. It would have two steering axles. The rear as I have seen done on a few rigs would be an electric hydro power pack similar to ones used to power dump beds. Simple toggle on the shifter articulates rear steering. Not that dissimilar to modern monster trucks. If you want to crab: steering wheel left, switch left. For tight turns: steering wheel left, switch right.

As with any modified steering I would not go over 35 mph with it. A deuce has no ROP and would be suicide.

 

[Kohburn]

if you are going full hyrdaulic then there is no need for a mechanical linkage between the two rear's you can link two hydraulic rams with tubing, and one feed tube to each ram. they are forced to move the same ammount (so long as you don't get a leak) and it still only uses the same amount of fluid as a single ram that way.

 

[mudguppy]

... there is no need for a mechanical linkage between the two rear's you can link two hydraulic rams with tubing, and one feed tube to each ram. they are forced to move the same ammount ...

this is not true - there is no way in ensuring that the two circuits stay true to each other without a mechanical linkage.

 

[hndrsonj]

Well I just read 7 pages of this. It went from a conversation of-is this possible to being a girly girl for buying off the shelf parts vice fabbing something whether safe or not. Here's my question-Aren't full hydro steering systems illegal in most states? I KNOW they are in TX where the origional poster is from. Just a thought, would hate for anybody to get sued when something happens and someone is killed........

 

[jesusgatos]

Here's my question-Aren't full hydro steering systems illegal in most states? I KNOW they are in TX where the origional poster is from. Just a thought, would hate for anybody to get sued when something happens and someone is killed........

Nope. This has been discussed at length in several threads recently...

 

[hndrsonj]

Nope. This has been discussed at length in several threads recently...

What are you saying, they aren't anymore? Can you elaborate? Thanks.

 

[jesusgatos]

Saying that it's not illegal in most states. Would post links for you, but I'd have to search.

 

[bratpackdad]

I'm curious to see who is going to try this first..

 

[Kohburn]

this is not true - there is no way in ensuring that the two circuits stay true to each other without a mechanical linkage.

it's not two circuits - it's one circuit with two cylinders in series. They are completely linked unless there is a leak or air int he circuit. the only slop in the system will be at the tie rods and other pivot points. which is no different than with seperate or mechanicly linked systems.

It has to be pinned for highway use anyways so that eliminates potential misalignment at speed.

 

[jamesfrom180]

Adding a cylinder give what advantage. With mechanical linkages one cylinder does all the actuating and the linkages basically provide all links. More cylinders would mean more points of failure.

If you are talking about the tandem axles I still think they will need two separate radii. Which could be accomplished by one circuit with a proportioning valve I believe. Still its a deuce and why are you on a trail or course so tight without ROP.

 

[Kohburn]

I don't see a mechanical linkage working on an articulated deuce tandem. there is too much movement that would misalign the wheels.

if you are worrying about points of failure then adding rear stearing on a tendem is not something you woul want to do because you just tripled the points of failure. for stearing.

 

[mudguppy]

it's not two circuits - it's one circuit with two cylinders in series. They are completely linked unless there is a leak or air int he circuit. the only slop in the system will be at the tie rods and other pivot points. which is no different than with seperate or mechanicly linked systems. ...

that's theory versus practicality - it's different. you'd have to use a dividing valve, which is close, but not absolute.

first of all, you can't do it with cylinders in series. this requires one cylinder to actuate fully before the other actuates, based on pressure differential. this also allows the two cylinders to cross feed based on dynamic pressure changes - this is bad.

secondly, you won't be able to do it with cylinders in parrallel without a dividing valve.

third, you can do it with a dividing valve which will get you close, but not close enough for reliable centering within the amount of error necessary for any kind of on-road driving, let alone centering lockout mechanisms.

you need to re-look hydraulic circuit fundamentals; it can't be done without a complicated electronic monitoring system or mechanical linkage.

 

[jesusgatos]

Geez mudguppy, that's a really good point. I totally over-looked the fact that the two axles would inevitably get out-of-balance if it was a purely hydraulic system. duh.

 

[mudguppy]

... first of all, you can't do it with cylinders in series. ...

actually, this statement is incorrect. it will work for a while - but you inevitably have cylinder creep and will find that your rears are no longer in-line with each other.

you'll have to crack the intermediate line and bleed in either direction to get the rears re-aligned.

 

[Kohburn]

you need to re-look hydraulic circuit fundamentals; it can't be done without a complicated electronic monitoring system or mechanical linkage.

Cylinders in series works but need to be double rod where the rod end flow of one cylinder matched the cap end flow of the next cylinder.

You do have to incorportate a method of being able keep them full plus have a way to resynchronize them when seals start bypassing.

You can handle this by using a small orifice that bleeds oil across the piston seal when the cylinder is fully extended. For a steering application this would resynchronize everything when the steering is turned to full lock.

The modern electronics for synchronizing system is just a refinement of the fundamentals.

 

[Unforgiven]

I looked at the rear suspension better today. The torque rods allow each axle to swing independently of the other axle. The intermediate drive shaft is splined to allow for differing lengths between the two axles.

A mechanical linkage would bind up when under articulation.

I don't see why a parallel hydraulic circuit would not work. It's only used off road at low speed. Like the other poster pointed out, the two axles can be brought into synchronization by turning the wheels full cock either direction & they have to be pinned on the road. I assume this is normally done by springs attached to the tie rod & axle housing?

I really don't think it's a necessity off road to have different turning radii on such a long wheelbase. Using a mechanical linkage, even if it were strong enough, would limit the articulation. Dual hydraulics would allow the suspension to work like stock. A proportioning valve could give differing radii if that is absolutely necessary.

 

[hndrsonj]

Saying that it's not illegal in most states. Would post links for you, but I'd have to search.

Here's the reply I got from PSC about adding full hydro steering on a deuce:
Full hydraulic is not legal or recommended for the street. You may be able to set it up with a Servo instead of an orbital valve and keep it street legal. The servo basically goes inline between the steering gear and the steering wheel and keeps the mechanical linkage thus making it legal. You will have to fabricate brackets for the pump and cylinder mounts.

Kelvin Jackson
PSC Motorsports
817-270-0102

 

[maynard83]

You mean like this?