rear steering

[tory]

so i checked around a bit and saw that several folks had asked about the GVW twords a rear steer and limitations and such...but has anyone with a bobbed duece actualy done it ? if so did they just hack off the front bit of a frame and weld it to the back, did they get really creative, did they use the guts of a big fork lift or some other multi-wheel steer truck to get crab, co-ordinated and other combinations of wheels moving ? i think a great theft deterent, since a lot of these trucks don't have keys, would be to leave them in crab. ha ha ha. pit falls, problems encountered, suggestions, please ?
idle hands are the devil's playthings !

 

[Recovry4x4]

Most folks that use the rear steer use a separate hydraulic control that whereever you release the toggle, it stays in that position. This gives you much flexibility as far as steering all, steering front or rear and crab actions.

 

[bbf]

i just pickup a 4 wheel steer buggy and i am having problems with it the rears are still moving a little when the the switch is off also i went with a hyd pump over the stock p/s pump that was on the truck with a 3 gl tank

 

[mudguppy]

there are several companies that offer full hydraulic steering kits for the rockwell axles because they are so popular in the off-road world. PSC is who i'll be getting my (front) kit from.

since i have a couple front axles already acquired, i was pondering putting one in back after i do the repower (after i get the truck...). it would be a basic bolt-in putting a steer axle out back. you would have to flip the diff chunk 180°, but that's not hard.

there are some companies that use an electrical power unit to drive a separate hydraulic pump, actuated by an electrical joystick or toggle switch. these can be really tricked out to give indication (via staged LEDs on the dash) to wheel position and automatic return-to-center or at the push of a button. other options are to use a separate hydro pump off the engine to power the rear unit. personally, i'm going to go w/ a manual control valve (in the cab) for reliability if i do it.

if you use one hydro pump to power both front and rear units you have to be extremely careful with your set-up, especially if you use a return-to-center system - the rear system may suck the power available from the front system leaving you w/out front steer.

anything can be done, and someone's already done it, too. if i decide to do it, i plan to create some sort of travel lock to ensure that the rear wheels don't/can't turn while traveling on the road.

btw, there is a member on here w/ a bob'd deuce and rear steer - can't remember the name...

 

[mudguppy]

hydraulic rear steer offerings from PSC, POS, Howe, Stazworks - there's plenty of options out there.

 

[IHASFIP]

Its not deuce related but, we are putting rear steer under the rear of our Chevrolet truck with rockwells. My buddy has it figured out. I know we are using a pump and reservoir from a dump bed trailer. Then to some variable switch. You can just bump the switch and move the rear tires any amount you want, and then if you push up on it, it will return to center. I wish I had a better picture of this guys setup but it was nice, and it used a joystick from some industrial crane or something. That was a long time ago when he told me. He owns a large offroad shop in east Texas. He actually made it to Top Truck Challenge. Few pics. White truck is ours. The muddy chevrolet is a buddy of ours.

D

 

[tm america]

rear steer is great but you need to have some way to lock it out if youre gonna run it on the street. its illegal unless you can pin it out.boyce sells a lockout kit .the monster trucks run a self centering setup which is probably best for most situations.just alot more costly .not only does it help you turn faster but you will get through more places .

 

[IHASFIP]

rear steer is great but you need to have some way to lock it out if youre gonna run it on the street. its illegal unless you can pin it out.boyce sells a lockout kit .the monster trucks run a self centering setup which is probably best for most situations.just alot more costly .not only does it help you turn faster but you will get through more places .

Yea, definately not safe for the street with out locking it somehow. We actually will drive ours on the street some but not much. And it definately won't be driven on the street until we change the pinion brakes over to 4 wheel discs.

D

 

[DUG]

rear steer is great but you need to have some way to lock it out if youre gonna run it on the street. its illegal unless you can pin it out.boyce sells a lockout kit .the monster trucks run a self centering setup which is probably best for most situations.just alot more costly .not only does it help you turn faster but you will get through more places .

It's illegal? GMCs and Chevy trucks had it as an option just a few years ago. (remember the commerical of the cowboy backing his horse trailer into a tight spot and the horse with his mouth open in amazment?) Not sure if it's still offered, but I haven't seen the commericals in a long time.

 

[DUECE-COUPE]

the chevrolet denali has the 4 wheel steer, but it is machanical. i have consided 4 wheel steering, but i think it will only be worth the effort if you are going to be rock crawling or extreme trail riding. the average joe needs both hands to steer and shift, so who will be running the rear steering hydrolics????

 

[IHASFIP]

[FONT=Arial, Helvetica, sans-serif]"Quadrasteer operates by sensing the driver’s desired steering input by way of a steering wheel position sensor. This information is fed to a microprocessor that determines the appropriate rear-wheel angles, based on steering input and vehicle speed. The microprocessor feeds its data to an electric motor which, based on algorithms, drives the rear steering rack through a planetary gearset.[/FONT]
[FONT=Arial, Helvetica, sans-serif]If a system failure is detected, Quadrasteer’s failsafe mechanisms revert to normal two-wheel steering."[/FONT]

I guess it is still mechanical...but not really any different than hydraulic. Think if somehow you lost all power for whatever reason. You would then loose all rear steering, that would be horrible if you were in the middle of changing lanes at 70 mph. I don't think that it is much safer being there is no direct mechanical linkage to the rear rack and pinion. I don't know I am just rambling...

D

 

[russ81]

I believe the "illegal" part comes in when your dealing with hydraulic compared to mechanical. Front or rear doesn't matter. I think you have to have a "mechanical" connection from the steering wheel to the wheels. With hydraulics you don't have that. Just fluid pressure.

I think it is the same with wheel breaks compared to pinion breaks. You have to have a direct mechanical connection to the wheels in case you break an axle or something.

 

[SR71BLACKBIRD]

My dad has 2 new steering cylinders off of a oshkosh truck (new) would work well with the heavy rear axle. I will be using one on my bobber and he may sell the other if interested.

 

[Militoy]

I drive my Gama Goat (6WD with 4-wheel steering) on the street - and even though the steering is 100% mechanical, getting a "feel" for steering at road speeds is definitely a learning experience. I have heard that the rare 4-wheel-steer version of the Scorpion rock crawler is the only one that is not street-legal - because it has hydraulic 4-wheel steering. I don't know exactly what federal DOT standard it might violate - but that's what I have heard several times. There are a few street vehicles with 4-wheel steer - but most of them are mechanical. The one quote I have seen repeated describing the non-mechanical systems on a number of sites rings true though - "The 1988-1991 Prelude stands alone as the only automatic stand alone all mechanical four wheel steer system. Everything else is subject to computers and hydraulic pumps, neither of which are known for their bulletproof nature."

<a href="What is Four Wheel Steering? - Four wheel steering</a>

Your life depends on reliable steering and braking. If you are experimenting with an off-road vehicle - have fun with it! If you are driving on the highway, think hard before you mess with your steering.

 

[tm america]

yes a mechanical link is needed to be legal 'i think some gm vehicles run rear steering. some trucks and cars but the amount of movement is really limited .the use and electric servo but as far as what any of us would be using rear steer for the only way to go is hydro with a way to lock it out for street use.

 

[mudguppy]

I believe the "illegal" part comes in when your dealing with hydraulic compared to mechanical. Front or rear doesn't matter. I think you have to have a "mechanical" connection from the steering wheel to the wheels. With hydraulics you don't have that. Just fluid pressure.

I think it is the same with wheel breaks compared to pinion breaks. You have to have a direct mechanical connection to the wheels in case you break an axle or something.

russ' is right on.

the GM quadrasteer set-up has been determined reliable because the failure mode is "straight." not so w/ hydraulic. hydraulic failure mode is.... well, all bets are off, really.

 

[IHASFIP]

russ' is right on.

the GM quadrasteer set-up has been determined reliable because the failure mode is "straight." not so w/ hydraulic. hydraulic failure mode is.... well, all bets are off, really.

Yea, I guess you are right. I just don't understand how in the event of total powerloss the rear could still function. Oh well I doesn't matter. Our truck won't be driven much on the street anyways. But will have fully hydro rear steer and hydro assist in the front. You can already turn the steering wheel with your pinky even with 44" Super Swampers.

D

 

[mudguppy]

... I just don't understand how in the event of total powerloss the rear could still function. ...

well... you can't - that's the "failure mode". since the failure mode will not cause an unsafe situation (wheels default to straight), it is considered reliable.

hydro assist is not illegal (in most places) because it retains a mechanical link. so failure mode of the system allows the mechanical portion to remain functional.

failure mode of a full hydro system results in loss of control. this is why hydro steering is not sanctioned for public road use.

 

[IHASFIP]

well... you can't - that's the "failure mode". since the failure mode will not cause an unsafe situation (wheels default to straight), it is considered reliable.

I wonder how it works being it is electrical. I mean if it loses power I wonder how it can still return to center as a default. I am not arguing. I am just curious. Yea, I know hydro assist is still legal in most places. Thats why we went that way. But even if we put full hydro in the front you still have steering even if the motor isn't running. Its just as hard as our deuce is sitting still though. Our tractors with full hydro steering can still turn if they aren't running, it just takes some serious elbow grease. Definately not the ideal situation, but it can be done.

D

 

[mudguppy]

I wonder how it works being it is electrical. I mean if it loses power I wonder how it can still return to center as a default. ...

ah. springs. the electronic actuator must overcome this to turn the wheels in any direction. remove power, springs push it back to straight.

...Our tractors with full hydro steering can still turn if they aren't running, it just takes some serious elbow grease. Definately not the ideal situation, but it can be done.

D

the steering valve is basically a hydro pump itself. it doesn't open a channel and allow flow like a control valve. rather, it displaces a specific amount of fluid as the input (steering shaft) is turned (which is why valves are differentiated by their displacements). the pressure from the pump allows this action to happen w/ leverage on your side, but in absense of power (i.e. the engine is off), the steering valve will still move fluid if the shaft is turned - you just won't have the leverage from the pump backing you up.

this isn't 100% transfer and different valve types will perform differently. obviously, in an emergency situation this won't cut it. but, you're right - if you could turn the wheel hard and fast enough, you could steer w/out a pump...