Still working on my front disc brake conversion (73 4x4). The stock 73 steering linkage uses smaller tierod studs than the 77-79s did, so I have to modify something in order to use the 77-79 d44 knuckles. Does anybody know if I'm gonna have a bumpsteer problem using a 77-79 tierod and drag link (due to the drag link not being parallel to the track bar)- or should I try to find someone to machine bushings for the knuckles so that they'll accept the 73-75 linkage? what kind of machine shop does this? I've had a really tough time finding info on this conversion- people do all the time with early broncos, but apparantly not so much with the full size trucks.

 

Is this a half ton truck you are working on ?

 

You will run into a bumpsteer problem if you run any type of inverted 't' or 'y' type steering if the trac bar and the drag link are not parallel.
These two links must run parallel because during normal suspension cycles the archs that they cycle at should be as identical as possible. If they are at different angles or allowed to travel at different archs, the result is movement, or feedback into the component with the least resistance, and this resistance is the steering wheel. This is a short explaination of bumpsteer, and why it works occurs.
Now, even if the tie rod ends are tappered a different size, you need to run the correct size, or you will ruin the tappered hole in the knuckle. Do not run any type of bushings or reducers to take up space. These will crush or wear in a hurry, and will creat an out of round hole in the knuckle and ruin the knuckle.
Fitting the correct ones are easy.
Probably a god idea to figure out why you are running into geometry troubles. WHich steering system design are you using, and is the tappered hole the only thing keeping you from making this right?
Little more information would be helpfull.

 

it is a half ton- f100. The steering geometry will be right if I continue to use the my 73-75 steering linkage. the problem is that my new knuckles for the disc brake conversion (from a '79 bronco) have a larger hole for the tie rod that uses a different taper. I've since checked the 79 bronco steering linkage- it will not work on the 73- drag link is too long and the mounting point for the link is too far over. somebody else has to have done this conversion 73flatrack said he machined bushings- as long as they are made of a similar material, have the correct tapers inside and out, and crush into the hole well, I don't see how it could be a problem. Still if there is another option for getting the right taper tie rod into these knuckles while maintaining correct geometry i'd like to know it.

 

This sounds like you are trying to use an inverted 'Y' style steering system.
The real fix would be to upgrade to the more desireable inverted 'T' style.
Inverted 'T"' will have a straight front tie rod and is not seperated, and connects the two front tires together. This should come from the donor axle that the disc brakes were taken from and then you only have to make up the drag link that also can come from the 79.
Not saying that the bushings would not work, I am saying that this solution brings another error factor, or possibility for failure, and I would not run a bushing that is so thin, especially on something as important as steering.
A failure here could only bring a poor outcome at best, and is just not worth the effort, not when there are other solutions.
I also believe that the bushing would actually crush around the TRE, and this would allow it to eventually work loose since a TRE is mounted in single shear. It will wear out and creat greater clearance from the inside out unlike a TRE by itself.
Just my opinion, but I would feel quite a bit more comfortable with a component that is easily replaced when on the road, even if this is a trail vehicle, than I would with a component that has some small one off pieces that can fail, and have no replacements out in the sticks
Anyway, once the system is converted to inverted 'T', getting the steering geometry is a snap, and will actually drive better by keeping both tires under control, and never allowing the two to run at different "TOE" measurements during suspension cycles like the 'Y' design.
Front tires will thank you for this and your truck will too.

 

There is a company called BC Broncos that offers the bushings you need. They use them for doing tie rod over conversions with F150 tie rods. Go to bcbroncos.com and click on steering.

If I were you though, I would do what it takes to run the 78-79 style steering. It is a WAY better setup for adjustment and steering feel (NO BUMPSTEER!!). You should be able to find a machine shop that can cut your drag link down and thread it. Then you can use a tie rod adjusting sleeve to fine tune it.

Is your 73 an open knuckle 44? What disc conversion are you using?

Jason

 

It's an open knuckle front end. The conversion so far is just taking parts for a '79 bronco and installing- the knuckles bolt up to the d44 housing. I"ve considerding using the 79 housing too- this has a higher trac bar mounting and a different length trac bar- the problem is that I"m pretty sure the mount for trac bar on the frame side is also different on the '79 so I may never be able to make it work without an adjustable trac bar, and even then if the pitman arm is different between 73-75 vs 77-79 the draglink and trac bar STILL might not be parallel. That's why I'm trying to go with the 73 housing, trac bar and steering linkage while using the bushings to compensate for the 73's smaller tie rod studs- this way I can be sure the steering geometry is right.


Now that I think about it I could just use the 79 housing, buy 77-79 steering linkage with a superliftr adjustable trac bar and drag link- then they'd be parallel but it would lots more expensive. Opinions?

 

What is the difference in length between the 73 and the 79 tie rod and drag link?

I don't see any reason to change the complete housing. You can always raise the track bar bracket to accomodate your needs. Once you have it where you want it, then do whatever steering correction you need (adj drag link, drop pitman arm), to get the drag link and track bar parallel.

Jason

 

The 77-79 tie rod and drag link uses a longer drag link that mounts to the tie rod closer to the rh edge. The 77-79 axle housing also uses a longer trac bar that mounts higher on the axle housing to match. Raising the the trac bar mount on the housing is just more fab work than I really want to do. If I had to go that way, the nuts and bolts of swapping the later housing in would be faster than all the cutting and welding of moving the mount. Still it seems like goint with the late linkage will take more custom machining or adjustable parts from super lift. And then after its done, I"ll still have to do a lot of adjusting before all the steeriing geometry is right with no bumpsteer. I know the stock linkage is right right now. I checked out bc bronco's site. I'm emailing them today to make sure that their busing for f150 knuckles with 66-75 eb linkage will work for me. I think it will. I also think that will be the most accurate and inexpensive solution. This truck will always be at stock ride height and only see the mildest kind of four wheeling. I just don't see the point in putting hundreds more into custom linkage for a truck that's not lifted and therefore really doesn't need it. Besides, I have a 76 bronco for the really rough stuff- I probably will do custom linkage for it just to get rid of that dumb inverted y lilnkage that came stock.

 

I did a disk brake conversion on my 75 F-100 4x4 and I used the oringinal knuckles. I bought a older drag link. I just had to drill too different holes for the steering box and install the drag link. It just took a weekend and I didn't even have to align the front end. I drive it everyday in the winter and it drives great. I can get you part numbers and answer any questions if you like. They have the conversion posted on this site. It went well for me. I bought the parts from a bronco site.