Technical Rack & Pinion Technical Question

My daughter and I are building a ’58 Ford F100 and our goal is to have it generally look like a 60’s poor man’s hot rod. My daughter is going to drive this so I am doing a power disc brake upgrade and a power steering upgrade. Most of my posts are in Ford truck specific pages and pages specific to the question but I was unable to find any forums that specifically deal with rack & pinion (R&P) steering. I hope someone knowledgeable with Ackerman steering geometry and radius might be able to help me with what I thought was a simple steering solution. It still may be but maybe I have thought about it too much. Attached is a picture of the front axle setup. The only difference of when this was taken and now is a disc brake conversion and shock mounts and it is on the truck.

So in a nutshell, I stuffed a big block FE Ford in the engine bay which left me no room to do the traditional manual steering box/power steering box swap that is common on these trucks. My options realistically (available room and available budget) are to leave the old sloppy manual steering or do an R&P conversion. They make bolt in systems but they will not work for me because I also did an axle over spring swap to lower the front stance. So I’m on my own to find a suitable R&P and make my own mounts. Not a problem for me. My issues are in the setup to make sure the Ackerman and toe in not affected when turning.

What I intend to do is replace the long tie rod that currently parallels the axle in a straight line from steering arm to steering arm with a rear steer R&P bolted to the axle. That way it moves up and down with the suspension eliminating any bumpsteer or toe in/toe out issues based on suspension travel up and down. I will use the stock steering arms mounted to the spindles and hopefully have enough room to mount the R&P so it is in a straight line between the two tie rod mounting holes. If there is not room, I will make sure the unit is parallel to the axle and the angles of the tie rods are the same.

With the stock suspension, when the wheels are turned full left then full right, the steering arms move in an arc and the tie rod stays parallel to the axle but moves closer to the axle as the turn becomes sharper keeping the distance between the steering arms constant. For example’s sake, let’s say it moves 2” closer to the axle.

My concern is when there is a full turn left or right, the R&P does not move but instead the outside ends of the tie rods on each side move forward towards the axle 2” while the inner end stays 2” away. This would mean the overall distance is no longer constant but is shortened during turns creating negative toe. I understand the length of the tie rods, the degree of arc created at the steering arms, and the distance they travel towards the axle will determine how much negative toe in is created.

So I think I have 2 questions. Any answers might create more though.

With a 51” overall length, is there going to be enough of a change to even notice or effect anything since sharp turns will be few and at slow speed compared to the majority of driving?

Is there a way to counteract this with vertical or horizontal angling of the tie rods (mounting the R&P higher and lower than the axle or closer to or farther from the axle)?

Any help would be greatly appreciated.

 

I'd like to see a picture.

 

Rack and pinion on a solid axle are not a good idea unless you use one made specifically for that application like the one Unisteer sells. I would use a new Borgeson cross steer box and adapt it.

 

I refuse to believe that a conventional steering box, especially a cross steer setup, is incompatible with an FE engine in your F-100 chassis. If that is the only reason you are trying to adapt an R&P unit, it is not a good one. The complications of the R&P with a straight axle create more problems than it solves.

Ray

 

292 until 1965.

Ray

 

I'm with Hnstray, I can't believe a conventional box can't fit with a FE. Millions of Ford trucks came from the factory with FE's and power steering. Sure, they were newer but the basic frame isn't much different. Why do you feel the conventional box won't work? I've never have seen a rack on a solid axle I ever thought was a good setup.

 

Rack and pinion on a straight axle is a can of worms. As the axle moves up and down, the steering shaft needs to telescope. And, they aren't made to do that. I have installed a Unisteer unit and it worked great. But they are frame mounted and cross steer.

 

Long post, comments in red.
I believe the stock style steering will fit with some modifications.

So in a nutshell, I stuffed a big block FE Ford in the engine bay which left me no room to do the traditional manual steering box/power steering box swap that is common on these trucks. My options realistically (available room and available budget) are to leave the old sloppy manual steering or do an R&P conversion. Rebuildable box ? They make bolt in systems but they will not work for me because I also did an axle over spring swap to lower the front stance. So I’m on my own to find a suitable R&P and make my own mounts. Not a problem for me. My issues are in the setup to make sure the Ackerman and toe in not affected when turning. The steering arms should accomplish Ackerman

What I intend to do is replace the long tie rod that currently parallels the axle in a straight line from steering arm to steering arm with a rear steer R&P bolted to the axle. That way it moves up and down with the suspension eliminating any bumpsteer or toe in/toe out issues based on suspension travel up and down. That is correct but the bigger problem comes from moving the steering shaft all over the place with every little bump. I will use the stock steering arms mounted to the spindles and hopefully have enough room to mount the R&P so it is in a straight line between the two tie rod mounting holes. If there is not room, I will make sure the unit is parallel to the axle and the angles of the tie rods are the same.

With the stock suspension, when the wheels are turned full left then full right, the steering arms move in an arc and the tie rod stays parallel to the axle but moves closer to the axle as the turn becomes sharper keeping the distance between the steering arms constant. For example’s sake, let’s say it moves 2” closer to the axle. It should pull one side of the tie rod closer the axle and move the other away.

My concern is when there is a full turn left or right, the R&P does not move but instead the outside ends of the tie rods on each side move forward towards the axle 2” while the inner end stays 2” away. This would mean the overall distance is no longer constant but is shortened during turns creating negative toe. I understand the length of the tie rods, the degree of arc created at the steering arms, and the distance they travel towards the axle will determine how much negative toe in is created. This should not happen. One tie rod will move closer to the axle and one move away.



So I think I have 2 questions. Any answers might create more though.

With a 51” overall length, is there going to be enough of a change to even notice or effect anything since sharp turns will be few and at slow speed compared to the majority of driving? Ackerman is in the steering arms, if it was there before its will be there still. If the steering arms do not have any Ackerman then bending them is the only way to get it.

Is there a way to counteract this with vertical or horizontal angling of the tie rods (mounting the R&P higher and lower than the axle or closer to or farther from the axle)?
Your biggest issue will be the steering shafts movement & it's a big one.

Any help would be greatly appreciated

 

Toyota 4x4 steering box fits unless you put the motor in some way that makes it in the way. Fit fine in my 60 F100. Need some pictures. What sort of caster numbers do you have with that axle over spring set up.

 

Wow, tough crowd here. Think I’ll hang out elsewhere where people want to help, 31 Vicky excluded. I appreciate the straight up answers with no opinions or a better than though attitude. I pulled the cab tonight and ran the steering full cycle. I see how the shape of the steering arms address Ackerman like your drawings. Your post answers all my questions and I appreciate it. This ain’t my first rodeo and I ain’t a snot nosed kid. 28 years in law enforcement and one thing I learned is when people are critical of a topic with people they don’t know it usually means they are unsure of themselves. So with that good luck with your forum. I won’t be back and I’ll make sure I pass on your sentiments in all the other forums.....

 

Cops never like being on the business end of a lecture......lol.

 

Can't handle criticism.
Easily triggered.
Fears superior intellect and knowledge.

Never would have guessed you were a cop.

Oh wait....


Sent from my SM-G900T using The H.A.M.B. mobile app

 

So with pictures...we see there is a clutch issue.

Personally, I prioritize steering and work out the exhaust/pedals/clutch mech next. Of course there are several balls being juggled so they all have to be kept in mind. I'm sure the clutch and exhaust can be reworked, but it's hard to guess exactly how much space will be available from pix.

 

Well I'd say on the rack mounted on the axle thing, Many of us have seen at least one solid axle rig with a rack cobbled onto it. There was a 39? Chevy gasser coupe that ran around the PNW with one for years on end. that was back in the 80's and early 90's. Looked terrible with all that hanging on an axle that was down in plain sight under the car that was jacked up enough to intimidate 4x4 Toyotas with lift kits. The owner said it drove great though. The steering shaft being able to slip to allow for the length changes with suspension travel is a real issue It has to move without binding but not have any slack in it.

I doubt the ackerman would be off anymore than on any independent front end with a rack. That brings up the question of how it is dealt with when using a rack with independent suspension? Is it even an issue? or just a pondering point?
Still Ford didn't change the frame on their trucks very much over the years and did run FE engines by the bunch. I think they went with cross steer when they went to twin I beam but that same cross steer box should work on a leaf spring truck with maybe some artful steering linkage. Or look at the 4x4 Ford steering with cross steer.

 

74 frame with twin I beam that was stuck under a 48 F1 but you are only looking at the steering box and where it sets.

 

did you read the OP's second post?

no more answers needed in this thread, methinks.

 

Cool your daughter is in on the build. she young or a bit older out on her own?
I got my missus helping with my current project getting dirty and hands on.
Much more fun with a bird by your side than another dude with opinions on every bleeping thing.
Hope you stick around even if its just for reading up and not posting. Some knowledgeable guys here but also a good sprinkling of old dudes who are totally one eyes traditional HAMBers.
Cant help or offer any advice on your build but best of luck all the same.

 

see ya ! you got some good info here ...and all the other forums already know about us...

 

Wow thanks (usually I'm the asshole.)
Just in case you glance back ,,,
In that great big post you forgot to mention the clutch issue.
There's a few ways to get the slave and that big old bracket out of there. Hydraulic throw out bearing would The first one that pops into my head

 

Simple solution to your clutch slave issue . Just convert to a pull cylinder and put it behind the throwout fork. Since it is not your first rodeo, a man of your obvious ability should be able to figure it out without any advice from a bunch of old smartasses.
My brother is an ex-cop and I don't like him either. I only talk to him when I have no other choice like once every 10 years. He knows everything too.

 

GM Chev's used steering shaft slip joints that worked, make sure it is the recall- replacement (on a model I found) if appropriate for 'length change w/susp. travel.' Jag made racks for heavier platforms. Your mounting considerations sound good, Level/parallel. Rough it in, mount a pair of rims, crank it end to end, and have a look at Mr Ackerman. IE; rear axle line, front axle, wheelbase separating, chalk & string, on ~ 2-bay open garage floor. Figure the Ackerman needed.

 

If there's any fairness in this world then we should expect an incoming ton of tech questions from users of 'other' forums which haven't been successfully resolved on other said forums . I didn't see any responses that could reasonably be taken as grounds to take offence, but what do I know? I do know there was a good thread on here using a cable as a puller on the clutch fork and that freed up a ton of useable room.

https://www.jalopyjournal.com/forum/threads/tech-clutch-cable-installation-w-pics.210569/page-3

Chris

 

https://www.jalopyjournal.com/forum...-older-only-please.236178/reply?quote=3717556
Take a look at Rootie's posts.

 

It's not the steering box getting in the way of the motor mounts. It's the reverse. There is no need to reinvent the wheel. It would be far easier to devise a different method of motor mounts than going so far out into left field. K.I.S.S. --- The most basic rule of rodding.

 

He appears to have a connection to “all the other forums”. A sobering threat indeed!