Does anyone have pictures of how they converted to a rack and pinion setup with a stock axle? I`m going to try it myself and would like to see some brackets made to fit to the frame and not the axle. I`m trying to do it myself with off the shelf parts and not have to purchase an expensive kit.

Thanks,

Oscar

 

I think you'd have pretty bad bump steer with it mounted to the frame, but i could be wrong.

 

The Toyota conversion is the cheapest and most logical way to go.

 

Just my 2cents but I would NOT consider that option. It would require a slip joint on the steering column and the suspension seems to bounce up and down a lot. If any other system was done it would have bump steer as Gicknordon suggested. I know they sell this kit but the roads in WA state are to rough and I could not do it. Why do you want to do it??? for power steering?? Toyota system would be much safer I think, That's what I'm going to do till the IFS swap.

 

I think one of the best ways to go is get a toyota steering box and put it in place of the original manual box along with a modified pitman arm. I have herd of the rack and pinion conversions being dangerous...that's just what Ive herd over the years on here but if someone were to setup one up the right way I don't see why it wouldn't work good. "Doc" on here bought his truck with a rack and pinion setup on a straight axle but he didn't like the way it drove and it wasn't setup very well. Him and I both went with a chassis engineering MII bolt in setup. I have seen many guys go with the toyota setup and been very happy . Sorry for the rambling

 

I too agree on Toyota box. I found a box on CL for $35 from wrecked truck only need a couple hundred in adapters and I'll be good. Many on here a better at fabbing things than I am I imagine they have less to buy.

 

How is your rack mounted? It looks like it is fastened to the frame. Do you get bumpsteer? I thought if I attached it to the axle I would be more likely to get bumpsteer. I assumed the frame would stiffen everything for better steering. I was going to fabricate something similar to the kit below.


http://www.unisteer.com/search_by_pr...rsion_kit.html

 

Mounting a R&P to the frame is a SERIOUSLY bad idea! It will hop around more than a frog on a hot expressway, and there is no advantage over the Toyota conversion to mounting it to the axle. Go with what works.

The instructions on the unisteer link aren't even for a solid axle vehicle.

 

Mine is mounted on the frame but i have an ifs so that would be the only way to mount the rack.
That kit is for a ford car i beleive which i think has ifs so thats why it mounts to the frame. I might be wrong though.

 

I saw that you have IFS , but where the rack mounts is to the crossmember which after welding is now part of the frame. That is what I dont understand. If I mount to the frame , it shouldn`t move around any more than one mounted to a welded in crossmember would. Some kits show them mounting to the solid axle, which would seem to be more prone to movement. The Toyota`s that some the steering gearboxes are removed from are to install a rack and pinion to the frame for better steering and handling. The picture below links to one that bolts to the axle. The suspension is going to move no matter what you have, IFS or solid axle. Still not understanding why I would get bumpsteer.

Thanks,
Oscar

http://www.google.com/imgres?hl=en&b...&tx=136&ty=102

 

The fact that you don't understand why you would get bumpsteer with a mis-engineered steering system tells me you don't understand the highly critical role that geometry and engineering plays into a steering and suspension system. No offense, just a fact. The pieces must be matched together with the correct angles, arm lengths, and move together. It would take way too much typing to even attempt to explain it all here. These links below might be some interesting and enlightening reading for you.

Start with this one...
Longacre Racing Online -- Tech Article "Bump Steer "

http://en.wikipedia.org/wiki/Ackermann_steering_geometry
http://en.wikipedia.org/wiki/Steering
http://en.wikipedia.org/wiki/Bump_steer
At any rate, your plan is incredibly ill-advised, and I hope you do your research before going forward.

 

52 Merc, I`m not trying to be argumentative but everything I`ve read except here is telling me that what I want to do will greatly improve my steering and control. I am a pretty accomplished fabricator and will ensure all my measurements and angles are correct. I just wanted to see how some of the other guys on here mounted the racks on their trucks. Two of the articles you linked to said ......Solid axles generally have zero bump steer. I wanted to see if the members had better results mounting to the axle or to the frame. I have already installed all new front and rear suspension. 4 wheel discs etc..This will be my daily driver so I wanted to go with a more modern steering setup without resorting to an expensive kit that I am capable of fabricating myself.

Thanks,

Oscar

Bump steer

From Wikipedia, the free encyclopedia


Bump steer or roll steer is the term for the tendency of the wheel of a car to steer as it moves upwards. It is typically measured in degrees of steer per metre of upwards motion or degrees per foot.
On modern cars the front of the tire moves outwards as the suspension is raised, a process known as the front wheels "toeing out". This gives roll http://en.wikipedia.org/wiki/Understeer The rear suspension is usually set up to minimise bump steer, where possible.
Typical values are from two to ten degrees per metre, for the front wheels.
Excessive bump steer increases tire wear and makes the vehicle more difficult to handle on rough roads.
Solid axles generally have zero bump steer, but still have roll steer, in most cases. That is, if the wheels move upwards by the same amount, they tend not to steer. I have already installed all new front and rear suspension.

 

Every member on here with an IFS has the rack mounted to the frame. The crossmember is welded to the frame. I can purchase a new rack for about a hundred dollars and fabricate everything else at work much cheaper than the Toyota conversion. Why would it hop all over? I`m just trying to see if the members had better results with the rack mounted to the axle or the frame. This will be my daily driver so I wanted to go with a more modern steering setup without resorting to an expensive kit that I am capable of fabricating myself.

Thanks,

Oscar

 

Again, Oscar, with all due respect and not trying to discount your abilities, you missed the most important part of the first article I asked you to read. Here's the excerpt...

In order to accomplish zero bump the tie rod must fall between an imaginary line that runs from the upper ball joint through the lower ball joint and an imaginary line that runs through the upper a-arm pivot and the lower control arm pivot. In addition, the centerline of the tie rod must intersect with the instant center created by the upper a-arm and the lower control arm (See diagram below).

The instant center is an imaginary point that is created by drawing a line from the upper a-arm ball joint through the a-arm pivot where it is intersected by an imaginary line that extends from the lower ball joint through the inner control arm pivot. Where the two imaginary lines intersect is the instant center.

Sounds complicated? Really it is very simple. To achieve zero bump the front end must be designed correctly. The tie rod must travel on the same arc as the suspension when the car goes through travel. Simply matching lengths and arcs to prevent any unwanted steering of the front tires.

To exaggerate, if the tie rod were only 10" long and the suspension were 20" long then when the suspension traveled the tie rod angle would shorten much quicker than the suspension arc. In this scenario the tie rod would shorten much quicker through travel than the suspension and the car would toe in drastically over bumps. The shorter arc of the tie rod would pull on the spindle and toe it in through travel.

Adding a rack and pinion to the frame and hooking it up to a straight axle is the exact example discussed in the last paragraph. Please think this through carefully. If not for your own safety, for that of the others on the road around you. You are treading dangerous waters. With a straight axle, the tie rod must be one piece from side to side.

 

This is exactly why a straight axle has zero bump steer. The solid tie rod does not change effective length as the suspension moves. It is not possible to maintain the effective length equal thru the suspension travel since the solid tie rod moves towards and away from the axle as the truck steers, a motion you cannot duplicate with a rack mounted to the axle or to the frame. You can fabricate the few necessary parts (mount, pitman arm) for the Toyota conversion if that's what is important to you. The Toyota maintains the stock steering geometry and gives you a high quality modern box with an ideal steering ratio for your truck with minimal installation effort and expense. Why reinvent the wheel by trying to make it square? The advice you have been given is good and "solid" (pun intended).

To give you as a definitive answer to your original question as possible: There are a lot of us on here that have done the Toyota conversion, only one or two that have tried using a rack mounted on the axle (AFAIK none are on the road yet) and no one that I'm aware of using a rack mounted to the frame, so take that for what it is worth. If you are dead set on being the alpha or beta tester, document your efforts and come back after you've put some road miles on it and post a report.