OldIHC

This just came to me...must be a after-lunch blood sugar surge.
Has bolting the steering rack and pinion unit to to the ancient I beam front axle become THE NORM?
I've worked on enough old vehicles with loose shackles to doubt it's a good idea.
Would anyone like to tell me why I'm wrong. I get how much faster the install might be.
I like to learn new things. Tell me why it's OK.

Funny that you mention this.

At the Yellowstone Rod show I noticed a mod made in this manner without any structural additions whatsoever.
I was curious and asked the owner , he had just purchased the vehicle and had no clue.
I wanted to to tell him how flimsy and unsafe it could be, but I am not a mechanical engineer and
kept my trap shut..

It just did not look correct or safe. Is there no requirement to have a modification inspected prior to transfer
Hell , how would DMV know anyway unless it was a ground up build and need new registration, even at that
I wonder how many times the DMV or DOT misses this.
Makes one wonder..

I agree not a good idea.

Harvey, time moves on and takes me with it.
When I was first working at Chevron (1975) , we HAD tire plugs but were not allowed to use them. We PATCHED everything.
And now...just about everything TUBELESS gets plugged...
If rack and pinion turns out to be OK bolted to the old I beam, I'm THERE.
Right now it looks...doubtful.
Better have plenty of stretch in the input shaft splines...better hope main leaves or shackles don't break...
Somebody tell me what extra steps you can take to make it SAFE!

I don't have an answer, or seen anything in writing on subject, but just looking at it, the slipshaft on the column wasn't designed for the that much movement. Even big truck slipshafts, which are built more along the lines of long driveshafts or PTO shafts, aren't used where there is that much movement in the shaft.
Attaching the R&P to the axle could be done with enough strength for the job, afterall, things like fork-lifts and other off road steering system do it that way, but the travel of the shaft is what concerns me. The amount of movement and the continuous movement in the shaft would be a the weak point.

It just looks wrong on a few levels. I would never wait for something like this to become illegal, it will never happen here. In the 1970s Ford had a hydraulic power assist mounted to the axle. The millions of suspension articulations may have contributed to the signature leaking.

So this is what I understand from this thread. I'm getting the message that it's not ok to bolt an R&P to the axle. So does that mean that you bolt the R&P to the frame and run tie rods to the front spindles? Please tell me how that is safer. I'm all ears on that one. The bump steer alone would be impossible to compensate for.

I get it too that a stock steering shaft isn't designed to be a constant slip joint. But I'm sure there are shafts available that are. Further more if the steering shaft was installed close to horizontal there would be a lot less sliding movement than if it was installed vertically.

Hoping to get some constructive discussion out of this.

I am not really understanding the issue. The design and workmanship needs to be good quality. The R&P unit can be mounted to the axle in a secure way and slip joints are available with long travel. Leaf springs shackles can be rebuilt. Like anything it needs to be well done but I am not seeing an issue with the fundamental concept.

Here is a steering shaft slip joint with 3 inches of travel. Because the steering shaft is at an angle U joints would be needed. Between the 3 inches of slip, the U-joints at an angle and the steering shaft being between the leaf springs I am guessing the wheel(tire) could move up and down 5 or 6 inches.

http://www.flamingriver.com/index.php/products/c0008/truckslipshaft/FR1856

If I am wrong please tell me why.

Guys, tell me a stock automotive application that mounts steering box or rack & pinion to UNSPRUNG components. Take all the time you need. Tic toc, tic toc.
You act as though I'm crazy to mention that it might end in disaster.

You're getting your Irish up and I'm just trying to figure out who said this was OK.
As I said earlier, new ideas occasionally show up that are somewhat controversial that finally get ADOPTED. Great.

Is this one of those? I'll go along if everyone agrees.

YES, you COULD surmise that the front I beam/ spring/ shackle/ frame structure on old trucks is WAAAY strong enough to mount the R&P on the axle. It surely LOOKS that way.

I guess the problem is that the (antique) spring/ shackle portion of it is made up of many individual pieces that can break or fall off. The topper is that full travel at the slip joint will change to markedly unsafe with these broken pieces.

Yes, I get the simplicity of it. Eliminating "Bump steer" is NOT a reason to do an unsafe construction.

Believe me, I'll be the first on my block with I beam R&P as soon as I'm convinced.

It looks scary. Is it unsafe?

Monsonmotors; in response to your first question about why we don't see R&P mounted to a solid axle on new OEM applications. If you are build a new vehicle from scratch there a simply better ways to do it. That in itself doesn't mean mounting an R&P to a solid axle on an old truck is bad it just means there are better ways if you are designing a new truck. You could also argue there are better ways to modify an old truck but again that doesn't make different methods bad.

You comment about old truck springs shackles and frames being old, worn out and weak is the same with stock steering. I don't see how R&P makes this any different. If you are going to drive this truck down the freeway then it all needs to be in good condition.

I fully get that the slip joint on the steering shaft will need to be greased and inspected. Depending on how much you drive the truck this may not be much of an issue.

I personally have never done the R&P on an old truck and most likely won't but I sure want to understand the good and bad about it. My current project is most likely getting a Mustang II front suspension. In the end I think this is a better solution for the money I am going to spend. I think by the time I did an R&P on the solid axle, fix the loose shackles, new king pins, disk brake conversion, etc I would will be within $500 of the MII.

Duane said:
"Monsonmotors; in response to your first question about why we don't see R&P mounted to a solid axle on new OEM applications. If you are build a new vehicle from scratch there a simply better ways to do it. That in itself doesn't mean mounting an R&P to a solid axle on an old truck is bad it just means there are better ways if you are designing a new truck. You could also argue there are better ways to modify an old truck but again that doesn't make different methods bad."

Duane, it's like building your house on the shifting sands. It's more like riding a galloping horse than steering a car.
THAT'S why manufacturers don't do it.