Since we are not apparently going to have a winter here on the coast I have had the Bird out for some work including doing my own wheel alignment. (Fastrac gauge and toe bar) Seems I have a fairly unsettling bump steer effect with the Granada spindles and disc brakes. Has anyone used a bump steer tie rod kit to correct or improve it? The kits are available several places.

57 Black Tbird 312/auto

Mark I have not, but I have installed a drop spindle kit (Drop em and Stop em) which I believe is a Granada Spindle. My car (Club Sedan) has yet to hit the road so I would be grateful to learn what you find out about this in the event I need to. I had not heard of Bump Steer kits so I Googled them. There are more images of bump steer kits than cats on the internet.

Mark

1956 Mercury M100
1955 Ford Fairlane Club Sedan
Delta, British Columbia

Isn't bump steer a result of the fact that the Tie rods are not parallel or the same length as the lower control arm? On T birds and 54-56 front ends the inner tie rod ends are line in line with the inner pivot point of the lower A arm but the outer end is somewhat different from the ball joint. Therefore as the wheel goes up and down (bumps) there is a geometric difference with the arcs of the outer tie rod end and the ideal location of the spindle arm to hold the wheel straight ahead and this causes the wheel to turn (steer) without moving the steering wheel. This is true for straight ahead or turning travel. It could be made worse if the Granada spindle puts the outer ball joint even further out of position. But even with the original setup there must be some angular steering of the front wheel on bump and rebound. So what kind of kit could there be that would reduce or eliminate bump steer?

With regards to bump stops they don't come into play with bump steer because they do not affect the geometry of the suspension.

Doug T

The Highlands, Louisville, Ky.

As I remember some of my ages old training and researching on the net here is what I have learned. Bump steer is the amount of toe-in created when the wheel moves up and down due to "bumps" in the road. The geometry for the best or minimal bump steer is engineered into the vehicle suspension by manufacturers design. Messing with the suspension with modifications messes up the geometry. One way it happens is swapping parts (spindles) and the tie-rods are moved off their original positions possibly. Bump steer kits or tie-rod relocaters are available to reposition the tie-rod at or near the original designed geometry. Measuring bump steer is done by cycling the ride height and measuring the degree of toe-in arc from 3 inches below ride height through 3 inches above ride height typically in 1 inch increments. Professional alignment racks have a bar clamp that is attached to the suspension and a crank to pull the suspension down and a gauge to measure the toe-in. I haven't done this in several decades and I don't have the alignment rack. Some of the procedures I found require removing the coil spring, reattaching the spindle to the A arms and cycling the suspension up and down measuring toe with a dial indicator. Going to avoid that if possible. I believe some after market companies make "dropped" spindles to compensate for bump steer by moving the axle spindle up the spindle assembly to lower the ride height but keep the original geometry or research applicable OEM spindles that accomplish the same thing. That is as far as I have gone today. On my car I hit a decent dip on the freeway at speed today and it went right on the rebound enough to get my attention firmly. I remember this kind of thing from the "olden" days of youth with heated/cut coils to lower a car. I need to recheck the alignment (caster/camber and toe) again and figure a way to load the front to bring the ride height down enough to make some measurements and get an idea of what the geometry is now. Also hoping some gearheads here with more smarts and experience can shed some light.

57 Black Tbird 312/auto

You are right Doug. My mental spell correct function changed bump steer to bump stop. I meant to say bump steer.

Mark

1956 Mercury M100
1955 Ford Fairlane Club Sedan
Delta, British Columbia

A friend of mine has some brand of diy home alignment tools. We tried to use them on my car after some suspension work earlier in the year (er last year). We followed the instructions to the T and I could tell just by looking at the wheel that the spec indicated was not the actual spec. I mean it was painfully obvious.

A quick search indicates that the Fastrax is the same idea, if not the same tool we used.

The flaw of the system is that you establish 0 by setting the tool on the floor, near the tire and adjusting everything to 0. Well, on a perfectly level floor, I see no reason it should not work. However, the average garage floor, driveway, road, etc is not level enough for the resolution required for most alignments. So even though the tire may have been aligned correctly relative to the ground directly under it,if the car is tilted even slightly because one tire is at a different height, and therefore each tire is on a different plane, the entire alignment will be incorrect.

Long story short,spend the dough to have it aligned at a shop with the high dollar tools and see if the bump steer goes away. I'd try to get my money back on he caster/camber gauge. The toe bar is useful but not really necessary if alignments are done elsewhere, anyway.

Lawrenceville, GA

I'm in the same boat, with the bump steer a result of relocating the rack to clear the FPA headers. I've seen bump steer kits installed on later model Fairlanes with lowered spindles, and on Charger. The owners seemed to be happy with the improvement. I think the kit came from Alston's Chassis works. There are some other mods going on to the front end, and when they're done, I'm going after the bump steer. I'd be interested in what you come up with.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

After further inspection......I need lower ball joints. Can't get a reliable measurement so that needs to be tackled first. Rockauto doesn't list them but NAPA does for 150 bucks a pop. Yikes. The online catalogue at Thunderbird Headquarters (near me) lists them for 50 bucks a piece. Scratching my head about the price difference. China vs American? The NAPA parts are listed as Rare Parts, no indication of where the Tbird parts house gets theirs. Any advice?

57 Black Tbird 312/auto

I don't know about the ball joints but in my quest to find the best control arm bushings I used moog from rock auto and napa. They were made in mexico but looked a lot better than the ones I got from one of the big name ford resto parts places.

I did some looking around on the Internet and the Rare Parts joints look to be good quality and made here in this country. They are also in Stockton, Ca which is also semi-local. After thinking about this for awhile, I didn't question the ball joints because I had rebuilt the front end when I bought the car maybe 12 years ago. I got the ball joints from a Tbird parts house and most likely they are Chinese in origin and worn out. Maybe 30 thousand miles. I bit the bullet and ordered the Rare Parts ball joints on line at 128 bucks a piece. Shipping is minimal for my location. At least they are bolt-ons and not riveted. Hopefully the steering problem will be corrected with the new joints and another alignment. I went to the MOOG website and they don't make them any longer.

57 Black Tbird 312/auto