Rack and Pinion?

Has anyone attempted r&p steering in the XJ/MJ?

I am fixing to attempt this, using front-steer rack (so that I won't have to change spindles) mounted to a custom cross-member / stump-jumper.

I need to completely omit the factory steering, minus the column and shaft. This is so that I can make room for my huge, overbearing, un-relenting diesel engine's front-sump oil pan.

I am going to get the engine in place, mounted where I want it, then worry with the steering. I say this because the diesel engine is so much heavier than the 2.5 gasser that came out of it, that I know I will have to change springs (hoping 4.0 springs will suffice). Once I know where the body sits in relation to the axle when at rest, I will mount the r&p as front-center to the axle as I can (hence why there will be a stump-jumper) so that there will still be room for articulation between compression and decompression of the suspension.

Ouch, I just had a thought, does anyone know how far the axle assembly shifts toward the driver's side under full suspension decompression? I think I just realized why I can't mount the r&p to the body. Maybe I can mount it directly to the axle... no, then stabilizer is in the way.... Brain hurts now, must take nap....

-Steven

Forget it........

Goatman said:

Forget it........

Click to expand...

Well aren't you just a ray of sunshine!
Help me out, be more specific, I am bound and determined to make this work, it's just a matter of how, or in this case, how NOT to do it.

-Steven

Goatman is right....Forget it.

try a hydo assist. much easier to set up, and stronger too.

I had a brief thought about that, but I canned that idea for the same reasons I'm trying to do away with the mj's original steering, interferance with the oil pan. The motor I am trying to fit has a front sump. A very LARGE and obtrusive front sump. I actually bought this mj because they have the solid front axle, and no natural crossmember. Because of the oil pan config, most all other foreign and domestic 2wd trucks are out of the question because the crossmembers are where the sump needs to be.

edit... and on top of that, this diesel is a 5-cyl, and most other trucks only account for four. Since the 4.0 I6 is an inch or two longer than the 5, it seemed the logical choice. Why is this project beating me up so bad?

-Steven

Where are you going to mount your rack? The rack would have to be mounted to the axle housing for it to turn the knuckles and allow the suspension to cycle but then how do you get a steering shaft to the rack that is now mounted to the axle housing?

Its just not worth doing. You will end up spending lots of money for something that can be done much cheaper and stronger the old fasioned way.

AARON

the ram assist will mount directly the the axle housing

NOT spending alot of money is the overall hope and goal of this project. I'm trying to utilize not only existing hardware, but from vehicles I already own. The r&p that I am playing with right now for measurement purposes is from a late model firebird (it was the first front-steer r&p i came across) but I've also been looking at the r&p from the ford mustang. I'm leaning towards the mustang's, because replacement cost for new or rebuilt r&p is much lower than the firebird's.

I've thought about mounting it directly to the axle, even went so far as to work out most of the bugs for the shaft linkage and how to overcome the suspension travel, but decided against it for two reasons:
1. at full decompression, how strong will the shaft actually be (telescopic)?
2. back at square one... the stabilizer bar is in the way

I can't do rear steering, not only because the spindles are backwards (thought about swapping them) but the control arm config interferes.

Has anyone mounted leaves up front? That would solve alot of my problems, but what would I mount them to in the front? The bumper?

Vee Dubb said:

Ouch, I just had a thought, does anyone know how far the axle assembly shifts toward the driver's side under full suspension decompression?
-Steven

Click to expand...

This distance will vary. Primary reasons affecting this dimension will be:

--Length of track bar

--Angle of trackbar at rest/ level ground

--Limiting factors (shocks, straps, dirty windshield,etc.)

Keep in mind that front to back movement occurs at one end of the axle or the other. Or both at the same time.

Good luck with the head scratching, careful not to kill any hair.

But IMHO, what they said.

Hydro

Now with hydro-steering, seeing as though the only setup I have ever actually laid eyes on was on an AG tractor, this is basically just a two-way ram, one side mounted solid to the axle, one end to the spindle, then a solid tierod between the spindles? The pump would be engine mounted, and two lines high pressure lines running to the ram, correct?

The setup seems pretty strait-on and simple, but my question is what activates the directional valving from the pump? I don't want to over-complicate what I'm trying to keep as simple as possible. Not only that, but I don't want to fabricate any more than I have to, so that when (not if) WHEN something breaks, I can buy another one and bolt it up, instead of starting again from scratch.

-Steven

can anyone link me to a picture or diagram of hydro steering? Maybe I just need a graphical push in that direction...

edit: I want to stay as mechanical as possible, and as far away from electrical as possible. One of the reasons why I want this diesel engine, battery is there to cycle gp's, start, and from that point on, the engine doesn't even care if it ever sees the battery or alternator again. There's nothing I hate more than an electricity-dependent NON-electric motor.

Since no one has mentioned the magic word yet, I will; "bump steer".

The arc described by the tie-rods of a r&p steering setup would create far more lateral movement than the track bar. You would create the worst possible scenario for bump steer. With the rack, axle mount is mandatory.

Have you thought about moving the existing steering box forward? Maybe doing so, along with a bell crank linkage would get things out of the way.

I actually thought that going to a power rack would eliminate bumpsteer, but now that you have me thinking, you are exactly right, if I do go r&p, it would have to be solid mounted to the axle. Thanks for bringing that to my attention!

As for moving the steering box...... ya know I never put much thought into that. The first reason why I neglected that idea, reading in the tj forums, and listening to some of the old mj folks, is that the factory mounting of the steering box was sorta weak to start with, and I figured the only thing I would be accomplishing by moving it would be to make it even more fragile.

Several reasons for wanting the steering box out of the way:
1. radiator mounting room, I'm not convinced the 4.0's rad would be sufficient
2. belt-driven accessory impedement. If I'm going to run ps and ac, I need that space
3. even with a mild lift, and a dp arm, there's no clearing the oil pan without extreme lift, then I've totally defeated my purpose of making a reliable vehicle.

I'm sure there's more options out there than I can count to do what I'm trying to accomplish (the hard way). I just haven't been introduced to them yet, or simply haven't remembered them.

edit: oh, and what's a bell crank linkage?

-Steven

A bell crank changes the direction of motion. Here's an example of one off an old Jeep:



As an example, you could mount a GM truck style steering box forward or rearward of the orignal mounting point. The GM box has a pitman arm that swings off the side of the box with a fore and aft motion. Run a drag link from the pitman arm to a fabricated bell crank that would change the direction of motion to side-to-side. Then attach a drag link similar to the factory drag link across to the passenger side knuckle

I think there is a chevy van that has a forward swinging pitman arm. That will let you move you entire front axle forward and out of the way.

But I'd look up station on Pirate4x4 and just go full hydro. No mechanincal linkage to worry about.

Ok, I see what you are talking about now. It took me a minute to get all the geometry right in my head.

Wow, just went to pirate4x4 and looked at Station's rig. I'm really impressed.

However, in my situation, anything even close to that would be an amazing case of overkill. Not only that, but I finally realized that I am NOT going to be able to mount the steering, hydro or r&p, to the axle. The rear for obvious reasons (control arms) and the front, well, back to square one. Unless I lift the suspension significantly, anything in front of the axle will interfere with the oil sump. Granted, I can set things in, and get everything working, but even with REAL solid bump stops, I would fear bottoming out into my oil pan. It's a shame this engine is so tall.

I'm going to have to spend a few more days laid out under my jeep. Maybe if I stare at it long enough, think about every configuration I have ever seen, just maybe, it will come to me.

Even if you wanted to install a small block chevy you would have to lift at least 3 inches and they have a rear sump.
Also the front leaf spring conversion has been done by some members here and there are some good write ups on it...... do a search and you will find alot of info.

Just for the record.......

The 80's ford mustang r&p is working wonders.
Welded a custom cross-member to mount it on, heated and bent the stabilizer.

Tie rod ends FIT.

Total investment:
$60 for reman'd r&p
5 hours welding and shaping c'member
5 years off my life for setting toe-in and experiencing death wobble.
my bad, it's now zero'd out and hasn't given me a bit of trouble.