So I was at work today, opperating the tractor/mini-zamboni and i noticed that the little tractor acctually had hydraulic steering, no steering linkage just the hyraulics. So naturally I got to thinking about my truck and started to wonder about full on hydraulic steering for my 75 F250. I know about hydro assist but what about full on hydro steering, anybody got any ideas? My first guess is a HUGE hydraulic ram. Just something fun i was thinking about...

 

Actually the ram used for full hydro steering is not that large at all, it's 8" stroke and typically a 1.5-2" bore. The better systems use a double ended ram mounted to the center of the axle which also functions as the tie rod. In addition, you need a load reactive orbital valve. This is a very common setup on rock crawlers/offroad rigs and the same basic setup that pro monster trucks use only they'll typically use 2 hydro rams. That being said there's always a lot of contreversy about using full hydro on the street. Many claim it's not legal to do but only certain states have laws which require a mechanical steering linkage. The big fear with doing this is that it will "fail" and send you off the road or over a mini-van full of kids. This can be caused by a failing hose or fitting and you have no backup mechanism for steering. Some people are afraid of losing engine power (therefore the steering pump) and not being able to steer. This is really not a concern as orbital valves will function as a pump in themselves. It would be very tough to steer, but would be about like steering your truck as is with no power steering: doable, just not pleasant. In terms of the rest of the system, IMO it's as reliable as you build it. We trust our lives to hydraulic systems every day and if they're properly maintained and inspected they function just fine. I've seen sector shafts break, tie rod ends break, joints in steering shafts come apart, etc. so there's plenty of ways the stock steering setup can fail. But the fact of the matter is that a mechanical steering system will typically start showing signs of wear before it fails whereas a hydraulic system will have no warning.

There's quite a few people who run systems like this on the street but nobody on FTE that I'm aware of. However if you do a search for hydraulic steering or hydro steering in the offroad forum here you'll find a lot more info on it.

 

As far as losing steering if the engine cuts out, you could put in an accumulator to give you a few turns. Aircraft use them all the time for stuff like brakes and steering. It seems to me full hydro would be twitchy at speed.

 

It's only twitcy if you use the wrong kind of steering valve which is why I specifically mentioned a load reactive valve. Steering will self center and you feel resistence on the steering wheel just like with a regular steering setup. The difference is that you don't have the slop that is often felt with the Ford steering boxes. It feels like a rack and pinion steering. The valve must me correct for your setup or it's not road safe. Most steering valves from forklifts, etc will not give you "road feel". You must also make sure that it's valved right for the proper turn to stop distance or it'll be either extra sensetive or you'll have to spin the steering wheel a lot of times to turn the wheels just a little which will make it too slow for the road.

 

That sounds like a ton of work not to mention money. I love the way you have your x-over steering set up Ivan. I think that will probably be a better setup up for my needs. For the x-over do you have to lift the vehicle first then determine the length needed or is it possible to do the x-over first then lift later? As of right now I have, I believe to be 1-2" add-a-leaf's front and rear on my 75 F250. My future plan is to go as high as 8inches, using leafs only.

 

I have heard that pure hydraulic steering is illegal for on-road use. There must be a mechanical connection. I may be wrong on that tho.

 

you are correct . the DOT does not consider hydraulic steering safe and it is not DOT approved.

 

Thanks, I could not remember how that went...

 

This depends on state laws. I have seen a couple states where the law specifically restricts it but a lot of them do not, such as Washington. Also take into account the fact that you already have vehicles that have hydralic steering on the road, like many (though not all) garbage trucks that can be driven from either side. It will be interesting to see what happens with the new sports car technology that is purely electronic and uses no mechanical connection between steering wheel and rack/pinion.

Grey, you can do crossover and then lift it. Your drag link will need to be lengthened when you lift it but if you build one like I show in my gallery you can just adjust it as you go. I've used the same drag link for 6 different changes in height. All I do is break loose the lock nuts and turn it to the appropriate length. Just make sure that it will clear everything under the truck with no lift before you build it. Sometimes the crossmembers can cause interference.

 

Yeah, I was looking at the crossmember issue today, it will definitly be a tight fit, I might just stick with the height for right now and order the springs then do the x-over, obviously i'll have to becasue the stock steering will no longer work. Are 78-79 Steering gear boxes interchangable with 73-77 F250 Frames and steering coloms and such? I can only find a drop pitman arm for 78-79 trucks...anybody know?

 

I got my drop pitman arm from bulletproof steering along with a custom lenth draglink. The pitman arm is not keyed so you can index it to where you need it. Also with no lift and your driverside spring compressed it might hit the bottom of the pitman arm and draglink. I have 4in of lift and bump my pitman arm doing some stuff I shouldn't have been.

 

460 Crew, thanks for the info, looks like a good site. Where did you get that front bumper from though, custom made?

 

NP Grey,Yep custom fabbed up by a shop here in town. Gave the guy a few Ideas and pics of what I wanted along with some requests and thats what he came up with, been pretty happy with it so far Only problem is it loves to eat those orange barrels and just really hard to keep out the back of bad drivers back windows in their SUWV's. LOL

 

Nice, if you don't mind me asking how much did it run you to have it fabbed up, becuase so far I am having NO luck finding a bumper that is built for our trucks!

 

I would also give it a thumbs down for on road use. Crap happens and it's nice to have a direct connection between your brain and the wheels.