Author Topic: Steering Idea: A "Fluid Draglink" (Read 6721 times)

DTB · « **Reply #30 on:** Nov 25, 2006, 01:17:34 PM »

Quote from: FIREBALL on Nov 24, 2006, 09:59:07 PM

Wow, I never thought i'd see this kind of pirate style bashing on this site.

I don't see any bashing going on.....just discussion

FIREBALL · « **Reply #31 on:** Nov 25, 2006, 05:23:06 PM »

"If you want to half ass it and ghetto it because you dont want to build it right thats yer deal.."

southernoffroader · « **Reply #32 on:** Nov 25, 2006, 05:34:19 PM »

I think this is a great idea and I have seen it in either Fourwheeler or Petersen's in the late 90's. I'll look through my old issues as I get the time and see if I can find it. A lot of you guys have your blinders on and can't see a good idea even though it's staring you in the face. Is this the perfect steering cure all, no but it is a good CHEAP alternative. I don't think it would work well for most of you west coasters as I think you would lose some steering force. This would be a perfect mud setup and work ok for most east coast wheelin'. You could always run hydro assist to regain steering force and be cheaper than any of the common alternatives.

79coyotefrg · « **Reply #33 on:** Nov 25, 2006, 06:04:07 PM »

Quote from: FIREBALL on Nov 24, 2006, 09:59:07 PM

Wow, I never thought i'd see this kind of pirate style bashing on this site. It wasn't all that long ago that some crusty old codger said what the hell do you need to go and cut out that perfectly good front end for and put that solid axle under there, or why do you need to do that cross over steering.
Come on guys.....the whole point of a board like this is to bounce ideas and be constructive.

Now...this system does work. I've seen it. Now I can't tell you how it would be on a daily driver but what the hell, give it a try.
Rhino doesn't live in Cali from what I gathered, so maybe it's not legal where he's at or maybe it is. But i'm pretty sure most of you are running rigs that are not really legal to be on the road either. So i'm not so sure why you're so concerned about that. I've seen plenty of rigs with fab work that I would leave the driveway with and those guys drive there trucks like they're sportscars.
Don't get me wrong here, safety is very important. There are some downfalls to this set-up, like losing a line, but with high pressure hydraulic lines the redundancy, pressure wise, would be very high, since the pressure in this system would be relatively low.
Let's not bash someone who wants to try something new, let's try and make it better if we can.
I say build it....let us know how it works.

RRMike · « **Reply #34 on:** Nov 25, 2006, 10:41:04 PM »

Quote from: southernoffroader on Nov 25, 2006, 05:34:19 PM

I think this is a great idea and I have seen it in either Fourwheeler or Petersen's in the late 90's. I'll look through my old issues as I get the time and see if I can find it. A lot of you guys have your blinders on and can't see a good idea even though it's staring you in the face. Is this the perfect steering cure all, no but it is a good CHEAP alternative. I don't think it would work well for most of you west coasters as I think you would lose some steering force. This would be a perfect mud setup and work ok for most east coast wheelin'. You could always run hydro assist to regain steering force and be cheaper than any of the common alternatives.

Not true. By differing the rams you can get as much force as you could reasonably expect by sacraficing travel (or turning radius). Since most rigs have boxes capable of more travel than the steering knuckles/axleshaft components you could lose some and still have full stop to stop travel with greater force then stock.

All you need to do is figure the throw on the pitman arm at it's end and the movement of the tie rod from stop to stop and it'd be a pretty simple formula to figure the two cylinder sizes.

6.72:1 · « **Reply #35 on:** Nov 26, 2006, 05:53:55 PM »

Looks interesting, but it is over my head!

RynothealbinO · « **Reply #36 on:** Nov 26, 2006, 06:35:03 PM »

Yeah, for simplicities sake I would probable get two matchin cylinders and then just mount it so it attached farther down or up on the pitman arm to adjust how much it will travel. I am not too worried about this because just looking at the steering system you can see that the pitman arm and the steering arm turn somewhat close to each other. As I said before just figure out the parnhard bar to steering arm movement ratio and maintain it. For those of you who understand this idea, how much resistance do you think I will encounter? I know it will be quite a bit but the only time that you need really powerful steering is when you are stopped. I have driven quite a few heavy vehicles without power steering and it is really not that bad once you are moving. Also, for those of you who still don't get it what could I do to better explain this idea?

RRMike · « **Reply #37 on:** Nov 26, 2006, 09:01:58 PM »

I would still measure and go with a slightly smaller diameter cylinder on the frame (than what you need with your current pitman throw) to get maximum pressure at the axle ram. Disco your drag link and measure too. I bet you have more throw in the box than you can use. Measure the full front to back throw and then measure the tie rod movement stop to stop.

I would think you will get less resistance with this setup than with your PS. Maybe about the same but I doubt more. Especially if you get a smaller diameter ram up top and just stroke it further.

FIREBALL · « **Reply #38 on:** Nov 27, 2006, 09:04:50 AM »

I agree Mike. It does make sense that you should be able to increase pressure a bit with a smaller ram at the box. Don't the early box's have a built in stop on the steering box bracket? It seems like I remember a couple of ears that stick out that the pitman arm hits at both ends of the stroke.
Rhino, also search steering pump mods. I think there are some fairly easy mods to get a little more pressure.

CTENG in KS · « **Reply #39 on:** Nov 27, 2006, 02:43:13 PM »

You will not be increasing pressure anywhere...pressure remains constant in a closed hydro system. Using a smaller diameter ram up top means you will have to put in greater force from the steering box and you will be outputting less force at the axle. In this situation you want to maximize the diameter of the ram at the frame to have any hope of pushing the tires and not overwerking the box and frame. Opening the fluid flow from the pump to the box will get you no gain in this case because you are still at the mercy of the steering box capability. It only helps for hydro assist because that extra fluid can be forced into the ram in addition to what the box is capable of.

Also, dont forget in your arm displacement calculations, the pitman arm moves in an arc and you will have to set the cylinder up at the frame to pivot with the arm to take advantage of maximun throw. This will require a little geometry.

southernoffroader · « **Reply #40 on:** Nov 27, 2006, 04:18:28 PM »

I don't see why you couldn't tap the steering box and plumb it into the system? I am no hydraulic expert by any means but I would love to hear from one. This thread has played out all of the personal opinions now lets hear a professional opinion. I hope you build it RynothealbinO and prove all these folks wrong. Like I said earlier i have seen this before and it worked, how well it worked I don't know.

RRMike · « **Reply #41 on:** Nov 27, 2006, 09:50:51 PM »

Quote from: CTENG in KS on Nov 27, 2006, 02:43:13 PM

You will not be increasing pressure anywhere...pressure remains constant in a closed hydro system. Using a smaller diameter ram up top means you will have to put in greater force from the steering box and you will be outputting less force at the axle.

Wrong. A lever is the same. You can move the fulcrum to increase power at the expense of distance.

Putting a ram with one square inch of surface area on one end and a ram with 4 inches on the other will result in a 4fold increase in pressure (total not PSI) from what is exerted on the smaller ram to what is put out by the larger ram. The internal pressure is constant, that is true but with 100 pounds of pressure (external pushing pressure) on the smaller ram you would get 100 Psi in the system which would result in 400 pounds of pressure (external pushing pressure[100 psi x 4 square inches) from the other ram with 1/4 the distance traveled compared to the smaller ram.

This is an extreme example to make the point. I know in this application the rams would be much more closely sized but using like a 1.75" and 1.5 inch ram would increase pushing power at the tie rod compared to what is being input by the pitman arm.

CTENG in KS · « **Reply #42 on:** Nov 28, 2006, 09:10:07 AM »

http://www.pirate4x4.com/forum/showthread.php?t=110680&highlight=steering+box+ram

FIREBALL · « **Reply #43 on:** Nov 28, 2006, 09:36:22 AM »

"I don't see why you couldn't tap the steering box and plumb it into the system?"

Good point. Why not?
It would be cheaper than buying two rams. You could use the parts list from the "hydro on the cheap" thread. You would be into it for about $120 or so.
I never tried unhooking my drag link to see if the hydro assist had enough power to work by itself.

CTENG in KS · « **Reply #44 on:** Nov 28, 2006, 12:22:37 PM »

Hydro assist werks on the residual fluid flow in the box. You would be MUCH better boring out the pump thingy and getting a hydro steering valve to run full hydro.

CTENG in KS · « **Reply #45 on:** Nov 28, 2006, 01:25:35 PM »

Sorry about screwing up the ratios earlier...I had to write it down on paper before I could admit that it is indeed a direct proportion between area and force output.

I was wrong.

RynothealbinO · « **Reply #46 on:** Dec 04, 2006, 08:57:15 AM »

The reason that I don't want to go full hydro is because I simply don't need it and don't desire to drive on the highwaw with full hydro steering. I have driven enough tractors with full hydraulic steering to know that it is not fun at 20 mph, so 60 would be downright scary. I just want to eliminate the need to depend on the drag link, which means that the suspension has to be designed around the steering. You guys are right, I could use two different sizes of cylinders to best maximize the full travel of both the steering arm and the panhard bar. Ideally when the steering box ran out of travel the knuckle would also be out of travel. Like I said before, you would just maintain the ratio of drag link to tie rod movement (or get as close as you could). But think about it, how many of you run out of travel at both the steering box AND the knuckle at exactly the same time. You should be able to get the ratio close to the same. I was wondering, what is the length of a cross-over panhard bar form eye to eye measured perpendicular to where the shaft on the steering box would go through? Or in other words what is the radius of the arc that the panhard bar travels on? And also the same question only relating to a crossover steering arm. It would be easier to measure this ratio on a crossover system than on a factory system. Thanks in advance.

RRMike · « **Reply #47 on:** Dec 04, 2006, 09:53:49 AM »

Crossover kits don't have a panhard bar and the ones people put on their rigs are custom so they can be any length they build them.

RynothealbinO · « **Reply #48 on:** Dec 13, 2006, 08:15:22 AM »

Yeah, I meant pitman arm, sorry.

RynothealbinO · « **Reply #49 on:** Apr 05, 2008, 11:01:33 AM »

So over the last year or so I have not managed to do anything with my trucks steering. I decided if the money is available I will be re-doing my truck this spring- new cab, flatbed, exo, rears up front, and rear 4 link or Chevies. I want to put the rear springs up front, but pull some leaves out until I only have about 2" of lift or so, but still have a pretty flexible setup. The problem is that I really cannot do crossover with this amount of lift without having to do alot of surgery and still limit travel. I also cannot leave the J-arm in place because it would have too much travel, even with a ball flip. So that brought me back to this idea after all this time. So I was wondering what the current thoughts on this type of setup are. Maybe somebody new will see this and have a thought or maybe people who had seen this before have had new thoughts on it. So...any thoughts?

93tonkatoy · « **Reply #50 on:** Apr 05, 2008, 12:13:43 PM »

This system would work if designed correctly, but a few things would have to be taken into consideration. First you would HAVE to use rams with IDENTICAL displacement on BOTH sides of the piston. Meaning, double ended rams. Single ended ram displacement is lower on the rod side of the piston than the cylinder side, because of the displacement of the rod itself. different diameters could be used to change the ratio, but the sizes increase/decrease in too large of steps to really tune it in well. The "fluid draglink" would HAVE to remain a CLOSED system, but could be joined with the normal hydro assist setup. The fluid draglink system would nowhere be connected (no hose connections) to the hydro assist ram or to the power steering pump or steering box. The difficult process might be to get the system bled out, but would work.

With this being a CRITICAL piece of the steering, you would also have to protect the shafts and seals on both of the rams from water, rust, mud, and dust. Any wear on the seals or shafts would create leaks, pushing out fluid and drawing in air, resulting in play in the steering feel.

This would be very interesting to see built, and to see how it would work. Along with others, I don't think I would reccommend this setup for the street, but for a trail rig, it should work.

OOPS · « **Reply #51 on:** Apr 06, 2008, 08:37:27 AM »

Quote from: FIREBALL on Nov 28, 2006, 09:36:22 AM

I never tried unhooking my drag link to see if the hydro assist had enough power to work by itself.

It will turn the wheels but only when the steering box is turned all the way to full lock turning one way or the other. Until it reaches lock the ram does nothing on hydro-assist.

RynothealbinO [OP]

RynothealbinO [OP]

RynothealbinO [OP]

RynothealbinO [OP]

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