falcon alignment problem...

well i've been racking my brain on this one, also nobody around here seems to know whats going on either. heres the situation. ever since i raised the car back up its been doing weird stuff. the toe changes drastically, i mean from 1/8" toe in to about 1" or more toe out upon accelleration! its totally undrivable now. ripped the suspension apart and replaced everything. new ball joints, tie rods, idler arm, springs, shocks, spring saddles, etc. also inspected everywhere looking for cracks or breaks in the towers & frame, cause this thing feels broken. everything there looked fine. the old parts i took out were pretty worn, so was hoping thats all it was but i wasnt. i limped the car to the alignment shop 4 blocks away, alignment guy did his best to align it, but said it needed a bumpsteer corrector kit, to lower the tie rod ends down. did that, but it still is fucked up. the toe changes so damn crazy, also as your driving it seems to raise the front end up pretty crazy, ride height changes at least 3 inches. i'm out of ideas & money, & right now the car is undriveable. anybody ever had this happen on one of these suspensions before?
my car is as follows, 62 ford ranchero, mustang disk brakes, lowered upper a arm (shelby mod) 65 mustang heavy duty springs.
i've seen so many afx comets & falcons raised up with the stock suspension, is there some alignment trick they are using? thanks for any info.

 

Hey Ricky! Chip here. I know that you said that you checked everything but did you check for spot welds broken between the inner fender panels and the shock towers? At rest with no weight on the front end it's hard to see, but you've got all the right symptoms. The other thing that makes me think is you used the term "drop the tie rods down". Shouldn't you need to raise them up to get them to level? You know how low my car is, (ya it's still sitting peacefully in my yard) when I did the drop on that I had to lower the tie rod quite a bit to get my geometry back to snuff. I had the same problems you described with toe changes. I heated and dropped the arms on mine, leads me to think yours should go up. How about some pictures underneath?
By the way your truck looks absolutely bitchin' gassered out, too cool.

 

hey Chip! thanks for the reply. the alignment guy i went said the tie rods needed to run parallel to the lower control arm, or close to it so its traveling in the same arc. it did get slightly better when i did lower them, but its still pretty bad. i'll get some pics up later of the situation.

so you still havent done anything with the falcon huh? hahaha

 

was it originally a six cyl car now running V8 spindles?

 

yeah Don, spindles are 67 mustang disk brake units. car was orignally a 6 cylinder before i converted everything back in 94. i drove this thing forever slammed & had no alignment issues.

 

Can't help but think that the mustang spindles have some sort of geometric difference that is holding this deal up. Steering arms shorter, different height, something. A couple of the bumpsteer corrector kits I have seen I was less than impressed with. Are the tie rods truly following the same arc as the lower arms? I think I would heat and drop the arms so that I could truly control the amount they were moved. Pretty sure those are forgings, shouldn't be a big deal. I think another tact I might take is to pull the spring out and set the height static, and just run the suspension up and doen through it's arc. Sometimes all is revealed just by looking in "real time". My biggest concern though is that you might just be beyond the usable misalignment range that your suspension will allow. Most suspensions have a point in their compression and drop arcs where they just will no longer work, and that point is usually at the ends of it's travel range. Kind of a long winded way to say maybe you went up to far, and maybe an inch lower would bring things closer to usable. That can be tested by doing what I said above.
No, mine still sits exactly where you saw it last. Got a few more parts collected up for it though - mitsubishi turbo, w/c T-5 & bellhousing, late eighties 250 six, etc. The new girlfriend keeps pointing at it and saying when?
Back to your trucklet, there is always straight axles!!!

 

Falcon (and early Mustang) front ends are known for having a huge toe in problem bear the end of their substantial amount of travel, Especially at full droop (which is the same as lifting the front end). jack up a stock one and you will watch the front wheels go crazy on toe when it gets near the top of the travel. If you still have 6 cyl pitman arm and idler arm it makes it worse.

what you will need to do is remove the springs, jack the car to your new ride height and then cycle it up and down from there while measuring toe. For there you can start moving the tie rod ends up and down until you alleviate the problem. The easiest way to do this is to get a rod end (heim joint) that is the same thread as the tie rod adjuster. use a normal bolt through the steering arms and then you can adjust with washers or spacers to get where you need to be. Once you figure that out, you can modify the steering arms to allow you to put the stock tie rod ends in that same position.

 

Mustang spindles from 64-73 have the same geometry as the Falcon V8 spindles.

 

that sure sounds like alot of work don thanks for the info, i have the idler arm, steering box, & linkage from a 66 v8 mustang. so you think the steering linkage needs to be moved up like chip suggested? i'm so damn frustrated with this thing. it used to be so much fun to drive. if i have to pull those coils out again its probably going to get a straight axle. did i mention a spring compressor broke and the spring knocked my ass out while putting it all back together? haha

 

You said that you put in a upper control arm mod simular to a Shelby mod. If I remember correctly this is for lowered cars so the upper control arm stays closer to paralell with the bottom one. If this is the case then when you raised it back up you messed with the Geomitry. Now when you accelerate the upper arm is pulling the top part of the spindle in way to fast and screwing up the toe. I may be wrong but I think this is the problem. Simple fix is to put the upper control arm back in the factory position.

 

You're OK on the linkage then.
It is a lot of work, doing things right usually is
my guess is it will need to go up bu t trial and error will get you there for sure.
OR that straight axle

 

I'm thinking a straight axle would fix things just fine!

 

Actually the Shelby mod had to do with camber curve. To keep the tires from falling over themselves when cornering. Idon't think they are hurting anything here, but not 100% positive.

 

I have about the same front end. How exactly did you raise it? The Shelby trick lowers it a bit.

 

just has heavy duty mustang springs with a 1 inch polyurethane spacer.

 

i wonder what the secret is to making it work!

 

Hotroddon is right as far as the Shelby mod goes. That shouldn't effect toe in at all. He also stated in very clear terms what I was trying to say as far as pulling the spring out and looking at things. Just don't knock yourself out!! I don't think you understood what I was talking about with what to move. The steering arms at the spindles will be the key, not the center link. Don't move that! That would be bad! If memory serves correct, the center link for a mustang is a couple inches wider than an early falcon anyway. I believe things got wider in '64 for the falcon.
I was just looking at the pictures you posted before I hit reply and noticed something. If you look closely at the Mustang in the top photo, you can see the tie rod ffollowing the same slope as the lower control arm. If you look at the picture of the red falcon below it you can see that the control arm and tie rod are not at the same angle. The mustang is what it should look like, theoretically. Might just be the angles they are photographed at,but that's what I see.

 

yeah i understood what you meant by bending the steering arm down, thats what i did yesterday to move it the same distance as the bump steer kits. it made a difference, but still isnt driveable. my suspension looks like the mustang pictured. i think i need to give it more castor somehow. 2-3 degrees positive is whats recommended with the shelby mod, but i only have .8 degrees. not sure how this affects toe though.

 

Don, I just reread this post and saw something that I didn't before. I didn't know think there was a difference in the the 6 cyl pitman arm and idler arm beyond tie rod end holes being different sizes. Can you tell me what the differences are? Thanks, Chip Quinn

 

Pictures?

 

i can't help but keep going back to what the Shelby mod is intended to do, lower the roll center IIRC and by raising the front you're defeating both intents by proxy? the raise is supposed to help transfer weight on takeoff in a straight line, and the Shelby mod is supposed to aid stability in handling? the stock geometry was never intended to do EITHER extreme and it seems that you have to pick your desired result, one or the other, but not both..... limitation of the basic design IMHO.

 

too many years ago i read a hop up book that gave the advice to set up cars that will experience a lot of front end lift under acceleration with up to but not more than 1.5degrees of toe-out to make up for changes in camber angle with the suspension unloaded. i don't pretend to have a perfect memory or completely understand the deal, but the gist of it was that when a car with toe-in lifted, it would pass zero toe and wobble like a grocery cart... how this translates into what you're experiencing i'm not sure of, but it was a big enough problem 30+ years ago to make the pages of something i was reading....
of course, back then it was all about the quarter mile and not the curves beyond them!

 

Chip if memory serves correct they are also a different shape, as were the steering arms at the spindle. That's why it doesn't work to ream the holes out on the idler and pitman when using V8 spindles. Don

 

Are you sure it's not going toe in under acceleration? Also, you might want to make sure the inner lower control arm bolts are tight and not shifting around and if anything, I would have thought moving the upper A arms down as shelby did would help keep toe in check, especially at stock height. The cars you used for examples look like they were at or near the top of their travel at rest and had minimal suspension travel to begin with. Maybe you could try a limiting strap on the upper A arms to help control rise and I can't really tell from the picture, but maybe the steering arms could come down slightly. Just try not to go to far, as shortening their length makes them more sensitive to movement.

 

If you lower the front, you lower the outer tie rods. If you raise the front, you have to raise the outer tie rods.
U sure you don't have a Mustang drag link or something non-Falcon?

Setting bumpsteer without a bumpsteer gauge is like target shooting blindfolded.

Find a dirt modified guy that does alignments.

 

I don't know about that. I'm pretty sure the outer steering link should for the most part follow the angle of the lower control arm, so they move in a similar arc and not fight each other.

 

That's easy.

See the angle of the upper control arm? As the chassis moves up, the upper arm is going to angle down even further, and move in an arc that gives the front suspension positive camber.

It appears at first that this would cause the front end to "toe-in".

But due to the short wheel base, the front steering arms have a great deal of ackerman angle built into them.

Unfortunately this has an adverse effect on bump steer as the lower control arm cycles lower than a level position. This happens because the outer tie rod end is inboard of the lower ball joint. As the tie rod moves in an arc about a shorter radius than the lower control arm, it "pulls" the lower steering arm inward causing a "toe out" condition.

The positive camber situation is also having an adverse effect on your toe-out condition (upon acceleration) because of the position of the outer tie rod in relation to the lower ball joint in a vertical plane. Do you see how it is lower? The lower ball joint is a fulcrum. Imagine the upper portion of the spindle as a long arm of a lever that pivots about that fulcrum. Now imagine the distance from the lower ball to the tie rod end as the short arm of the lever.
It is easiest to "see" this as an imaginary line through the upper and lower ball joints that continues past the lower ball joint (lower leg)...

Now, as you move that line in a positive camber direction, the "lower leg" would move outward of the lower ball joint.

Now, if you turn that imaginary line into a fork, with a tine intersecting the outer tie rod end, and moved the line in that positive camber direction, the tine would be restrained by the tie rod end (and tie rod)

That restraint would cause the fork to pivot about the axis of the imaginary line in a "toe out" direction.

A quick and dirty fix would be to move the outer tie rod/steering arm point up higher than the lower ball joint.

Doing so might fuck up something else... but it would help the toe out situation upon acceleration.

Sam

 

i'd bet all of those cars have even stiffer taller springs so the suspension is locked up against the snubbers.

sam is on the right track, and the shelby mod made the situation worse.

personally i think the car is talking to you, it wants to be low again.

 

I believe you meant to say negative camber and I think you've got something there with the steering arm being below the lower ball joint, since it would tend to cause toe out as the spindle gets into negative camber. Also, I'd think having the tie rod and lower ball joint in line would be better, as moving the tie rod above the ball joint would cause toe in under the same circumstances, but the inner tie rod axis may play a small part as well? I am also not conviced the Shelby mod had any negative effects, as it would tend to lessen the camber extremes that would contribute to this problem. Now my head hurts.