4 Wheel Steering ?

[over2land]

So, say I've got a buddy with an M725...

Say he wants to make it 4 wheel steer...

Say he wants to replace the front and rear axles to do this...

What do I need to know?

Is there somewhere to go so I can look at hydraulic setups?

Is there anyone here running 4 wheel steer?

Prolly not going with linkage, and gonna run a shutoff so on the road he can lock the rear out.

So, will Front D60's work ok, or no? It's mainly gonna be an on road vehicle. Some soft wheeling possibly. Say from a Ford or chebby?

Thanks guys.

[Zack172]

If its gonna be an on road vehicle why do you want to do this? Sounds like a total waste of money.

[over2land]

Well, where is the extra cost?

Aside from the hydraulics, which he can get pretty cheap... the front axle will cost me the same as the rear one will.

And, why'd GM come out with their Quadrasteer setup? (which, if you haven't used it, is a sweet setup in certain situations)

[over2land]

Originally posted by Zack172:
If its gonna be an on road vehicle why do you want to do this? Sounds like a total waste of money.BTW, thanks for the response that answers no part of the original question...

[ March 23, 2004, 08:59 AM: Message edited by: over2land ]

[GaWag]

The only way I know to do 4 wheel steering is to get 2 front rockwells.

I don't think 60's would work. If you turned the axle over to get access to the pinion it would run backwards I think.

Just my thoughts. I could be wrong.

Steve

[jode]

Well – I’ll start this off by stating that I have never done rear steer, and I don’t know a whole ton about the way the different hydraulic cylinders work.

Seems to me like as long as you are grabbing front axles for your rearend, any one will do…so grab that Dana 60. I think caster angle will be important, and I think that you may want to run a lot more caster than you would in the front. In the front, the caster has to be balanced so you get “return to center” a little bit, but so that it is also not too hard to turn at speed. In the rear, you won’t ever really want it to turn at speed, and you will want a lot of return to center, so I would think the increased caster would be beneficial.

Also, note that when the 4x4 magazines have done this mod (reference the Chevy Avalanche that fourwheeler did) they set it up so that a solid mechanical linkage could be hooked up for road driving. I think they just used a set of quick connects so they could engage/lockout the rear steer in a relatively short amount of time. If you think about it, having your rear steer go haywire on you (for any reason) would likely lead to a rollover in all but the slowest of speeds. If you are going to use it on the road, I can’t help but think that fourwheeler (or was it Petersons?) hit the nose on the head with their lockout idea.

Back to what I said about not knowing much about the different types of hydraulica valve applications available, I don’t know if there is a valve out there (or a way to combine a few valves) so that you could enable the rear steer to act automatically in conjunction with the front one (for decreased turning radius). Most people that do this on 4x4s do it not only for the increased radius, but also to be able to “crabwalk” the rig by turning both axles to drive the rig sideways. To do this, they set it up so it isn’t automatic and the driver actually “steers” the rearend independently from the steering wheel. I hear this takes some time to get used to and good at. So Zack’s question “why do you want to do this?” is actually quite valid as it will likely determine the way you end up wanting to set up the final system.

GaWag - how are two front rockwells different from two front 60s?

[joe]

Don't(or didn't?) recent Chev trucks have a 4 wheel steer option? Seems I remember some commercial regarding that. You might want to go look at one and see how it's set up. I think supposedly they have a lock-out system for hwy driving. Sure would get exciting though if the lock-out failed on the hwy and you're turning for an offramp. :(

[jode]

Yeah the chevy trucks have it as an option. In fact, Apparently chev just reduced the option price from like $4-5K to like $2K since it isn’t selling that well. Their system only turns the rear wheels a few degrees and is completely automatic. There is no independent operator control (AFAIK)

[Berrett]

Originally posted by GaWag:
The only way I know to do 4 wheel steering is to get 2 front rockwells.

I don't think 60's would work. If you turned the axle over to get access to the pinion it would run backwards I think.

Just my thoughts. I could be wrong.

Stevewhat you do is get a rear 60, then weld on all the outers from a front 60. but like mentioned, if it is not for off-road i wouldnt waste the time or money to do it.

[robselina]

we talked about it a while ago here, may find it if you search. mostly it came down to this:

1- a front axle will work and will rotate in the right dirrection, just gotta deal with the offset pumpkin.

2- you can weld on your outers to a rear axle and go that route

3- find a junked chevy with the rear steer and steal it complete.

as for street, it's going to be very hard to make it usefull. the chevy system is very smart, it turns counter to the front steering at low speed (to make a tight turn for example) and it turns with the front steering at high speed (for increased stability on the highway and towing applications) building in the brains to make a system like that from scratch is not going to be easy.... as was previously mentioned, most of the DIY applications are intended to be locked out for street use, but you may be able to use a self centering ram or something like that and maintain some off road functinality...

[jode]

Here’s another non-traditional idea. Instead of swapping out the rear axle, use a triangulated 4-link on a regular rear axle. Then, instead of hooking the links directly to the frame end, hook them into the ends of hydraulic cylinders. This would give you the option of increasing and reducing the wheelbase a few inches (shorter for better turning, breakover – longer for better climbs/stability), and it would allow you to pump one side out and pull the other side in so that you would be changing the angle of the rear axle to a certain degree. It wouldn’t create a drastic change in the turning radius, but it would definitely give you a bit more maneuverability. I saw some guy in one of the 4x4 mags running a set-up like this. Thought it was really innovative. It would be tricky to maintain the correct geometry of the 4-link though, what with all the angle changing that would be happening when you moved the cylinders. I’d have to give a setup like this a pimp factor of 9 out of 10

[over2land]

Jode- Thanks for all the input.

Yes GM does make it. It's called Quadrasteer. And, IIRC, it's computer controlled. That won't work for this application, nor do I think the axles in those trucks are heavy duty enough for this.

I like the idea of the links... but dunno if that'll be feasible here.

Do you all think that 60's will be strong enough?

[Zack172]

A rear dana 60 is about $150, and a front is about $1000. Then you have to rebuild them. I'd call that extra cost. Just my 2 cents.

[Bob Barry]

There are no "bolt-on" kits of this sort. Everything would be custom. The cylinders are sold through many places, but the plumbing for this setup would be completely fabricated.

Of course, you could drive it into a 4x4 shop and write a big check for them to custom-fabricate all this, but count on writing a REALLY big check ($5k-$10k, depending on what's done).

A front D60 would work just fine in the rear, though it wouldn't be as strong as his current D70.

I do agree with Zack172's first post, however. In response to your question "What do I need to know?", I agree with him that unless your friend has more money than God, this modification will serve no useful purpose for the intended application and hence, would be a waste of money. I think that's the most important thing you need to know.

[Zack172]

Thanks Bob.
Over2land, I wasn't bashing your friend, just saying I don't understand why he'd want to spend so much for something he doesn't really need....

[over2land]

Originally posted by Zack172:
Thanks Bob.
Over2land, I wasn't bashing your friend, just saying I don't understand why he'd want to spend so much for something he doesn't really need....AH, ok then sorry man.

Just kinda thought that it was a smart *** remark.

Just a bit on me, and my bud who's doin this...

he's got a business, and make (yes, fabricates, from the ground up) dirt track racers and carts (brfab.com, IIRC). Me, I've been in this for more than a decade already, and have done all of these things before, in one shape or another.

I can get D60 fronts (or rears) for 200 to 300 bucks each. don't matter if it's front or rear from my source. And then, I whatever is needed to set them up for the truck in question, I can either do, or know a dude to farm it out too...

Is it my way? No. I am going with a 35 spline conversion on the front of my 715, and leavin the rear alone. I don't particularly want the added complexity of the 4 wheel steer, nor to I want to modify the stock appearance that much...

But, for his application, I think it's worth it. That is, if it'll prove durable enough.

[over2land]

Oh yeah, and on the "bolt on" thing...

That's gone the way of Santa Claus, and the Easter Bunny. If I don't have to weld, or drill too much on something, then I still consider it "bolt on". Hell, can't remember the last bolt on thing I did, truth be told.

[Bob Barry]

Well, given the further circumstances you describe, two things:

1. Hook me up with one of those $200 front D60's. Seriously, I can use the entire hubs off a Chevy, or would take a whole axle with a 4.10 ratio for that price. I'd drive to Jersey.

2. If he's got the setup you describe, well then he'd be one of the rare people for whom this might be feasible.

Of course, it's going to involve a COMPLETE top-to-bottom fabrication on your friend's part. His best bet would be to search the General 4x4 Tech forum over on the Pirate 4x4 bulletin board and bone up on 4ws tech with a hydraulic rear cylinder. There are a number of ways to do it, but they all involve getting a 2" hydraulic cylinder, some plate steel, a hydraulic pump and a bunch of hose and a control valve, and then welding and fabricating until you've got an axle in back that can steer its wheels. smile.gif

[waggin'ear]

I call seconds on one of the 200.00 D60 fronts please! I am not kidding either.

[over2land]

Let me see what all he can get me (nother dude, and I'll get back to ya)

Email me what you need, and I'll ask him if he can get it. Need to know what it's out of, or side or pumpkin and WMS to WMS. Or all of the above.

[JEEPPICKUPMAN2]

nor do I think the axles in those trucks are heavy duty enough for this.
iirc they are dana 60 rear end with that rear steer option just like you are thinking of using

[Merc69]

over2land I'll take one of those $200.00 to $300.00 front ends also...I'll make the drive. Last one shipped cost almost $400.00 in shipping. I'll send an e-mail.

[robselina]

sign me up for a D60 for $200-$300 too. I'd prefer a ford drivers drop, but for that price I'll take a chevy or dodge too! road trip time!

[tomd]

Originally posted by JEEPPICKUPMAN2:
</font><blockquote>quote:</font><hr /> nor do I think the axles in those trucks are heavy duty enough for this.
iirc they are dana 60 rear end with that rear steer option just like you are thinking of using</font>[/QUOTE]On the newer Chevies this is correct, i've seen it, but i'm thinking its electronically activated (like steered) along with being computer controlled... Maybe just grab it, yank the electronics and put a hydro ram on? Centered steering rear diff?

[rockcandy]

If he has he cash flow...just use a front 60 cut down the long side tube and respline the inner axleshaft, then retube the other side and get matching inner-shaft. Weld on outer parts and voila, a rear steer axle. It wouldn't be too expensive if you can source a complete axle for $300. You figure about $100 to have the axleshaft cut/resplined and maybe a couple hundred more for the other inner axle. You can use the same outers, although you would want to upgrade to the 35 spline outers for sure in rear steer applications(more money). If you can source a 60 for $300 I would imagine you could fabricate a rear steer axle and get necessary components to make it work for about $1000....

[over2land]

******, well the price on axles is up now... 700 for one front axle.

Still, not too bad, but not what I was planning on.

And, my bud is gonna prolly ditch the rear steer. He thinks it'll blow the budget he's got for the truck. He'd rather put the money into the engine....

Thanks for the input though guys.