Did I really mess this up? Rough alignment issues (uneven tie rod length) after steering box and spindle replacement

[chrismalish]

Gentlemen (and ladies), I would appreciate any thoughts on my situation. Car is a 1969 Dart Swinger 340.

I Just replaced manual steering box with Peter's BAC Borgeson unit, and the spindles with Cass/Doctor Differential spindles for Stage 2 disc brakes so I could move up to 5x4.5 bolt pattern. These spindles/knuckles have longer steering arms than what was on there, requiring the tie rods to be extended (leaving tie rods unchanged = pronounced toe out). To put everything roughly back together with wheels, car required more extension on driver's side tie rod than passenger side in order to have both tires facing forward or slightly toed in -- by several turns, maybe ½” to ¾” longer. This had to be done with car jacked up, but still looks good now that it is on the ground. I have not driven it yet.

Currently:
-- steering wheel is straight
-- Appears to be same number of turns lock to lock: ~1-1/3 from center to either direction.
-- I believe the stops to either side are the steering stops on the steering arms hitting the control arms, rather than running out of travel inside the steering box.
-- but as I said, tie rods are noticeably uneven....

Not sure how I could have messed this up, but maybe I did. Presumably this needs to be fixed, but not sure this can be fixed by shortening the driver side and lengthening passenger side, as I think this would result in wheels being oriented in a slight left hand turn -- which means to bring it back to center, I would have to take the steering box off-center (or at least where it currently is). Do I understand this correctly?

I understand that if I wanted to redo the whole shebang to double check my work, I could

1. Separate steering box from pitman arm.
2. Turn steering wheel back and forth to verify box is at center of travel. Re-mate to pitman arm.
3. Even the length between the tie rods and reinstall
4. roughly re-center the steering wheel if noticeably off by popping off the coupler, turning as necessary, and reinstalling (Borgeson unit and BAC coupler do not have master splines; steering wheel to steering shaft do...).

Questions before I go down this road:

1. Can one can get enough separation to allow the box to turn freely just by popping the pitman arm at the box without also unbolting the box from the frame, or the pitman arm from the center link? If so, maybe this is the path of least resistance...

2. Is that even necessary though? Hard to believe I stabbed the box in off center. However, Borgeson box is a bit hard to verify TDC (or whatever center is called on a steering box) when not on car, as lock to lock is not a nice round number. Instructions direct:

“Center the new box by turning the steering box from either left or right stop to center by approximately 1 13/16 turns. When the box is on center, turning will become stiff. Since the stiff portion of the sector does not provide exact centering, it is helpful to look underneath the vehicle when the pitman arm is fitted. When centered, the center of the pitman shaft and the grease fitting for the joint to the center link will be in direct line or very close with one another front to rear.”

I got close to center with the box on the bench (with master spline on box ~ fore/aft), then rationalized that installing the box on the pitman arm would force the box to center of travel, as:

• The steering was centered when I drove into the garage
• Pitman arm has master splines, which allow box output shaft installation in only 4 orientations, 90 degrees apart.
• Distance from center link to steering box means Pitman arm can only be stabbed in one position: splined hole pointed to front and as close to box mounting location as possible. This puts master splines in pitman arm roughly fore/aft.

My assumption (and maybe this is wrong) was that if the box output shaft had to be twisted significantly (e.g., up to a quarter turn) mate to the pitman arm, that would translate into something like a full turn at the steering column input shaft, which would have been hard to miscalculate….

Also, after installation, I verified that in fact “the center of the pitman shaft and the grease fitting for the joint to the center link [were] in direct line or very close with one another front to rear.” I suppose that the box could be installed off center of travel and and allow this orientation, but then I would think there would be a huge disparity between turns lock to lock (like one turn to left, three to the right?), and that one would run out of travel inside the box before the steering arm steering stop hit the control arm on the "short" side....

Although I do want to take the car in for professional alignment, I don’t want to take this to the alignment shop if things are seriously out of whack and they can’t fix it by adjusting tie rods/caster/camber at upper control arms. First of all, nobody around me wants to even work on these older cars anymore, and definitely don’t want to mess with if there is something complicated wrong. And I don’t want to have to have it towed to the fancy race shop 25 miles away which will be expensive (tow, plus “specialist race car technician and alignment equipment” BS) and time consuming (for me – and this project has taken 10x longer than expected already….).

Thanks in advance for your thoughts.

Chris

 

[Demonx2]

@72bluNblu is a good resource.

For the avatar car, I had to get the tie rod lengths close as the toe change when the front end lifts is dependent on tie rod length. I used the Direct Connection (Mopar Performance) Chassis Manual book to measure/set mine. It forced me to have to pull and recenter my steering wheel but I have an aftermarket wheel anyway.

If the car is a daily driver or weekend warrior, I don't think I would worry about it.

 

[72bluNblu]

First, thank you for the detailed explanation! Really makes it easier to follow what’s going on. Now, to confirm a few things

-the pitman arm has master splines that only allow 4 possible positions on the steering box (only one of which can be correct for this application)

-the steering coupler has no master splines at all

If that’s all true, the issue is almost certainly that the steering shaft/coupler are not quite center of travel for the steering box. Could be for a lot of reasons but keep in mind that your steering stops, or even the suspension points of the car, may not be perfectly equal side to side. So equal turns on the steering wheel might not be the middle.

what I would do is

1- separate the coupler from the steering box

2- make the tie rods equal length, setting so your wheels are straight ahead. Don’t even worry about the toe in, because it’s gonna be the same side to side and it’s easier to verify the wheels are straight ahead.

3- verify that the steering box is relatively close to middle of range, and proceed if it is

4- put the wheels back to straight ahead, and make the steering wheel straight when you hook up the coupler.

The wildcard in this is #3. If the steering box isn’t in the middle when the tie rods are equal length, you’ve got to figure out why.

Again, my understanding of the Borgeson box is that the pitman only goes on 1 way because 90° off is massive. So if you can’t change the pitman on the box, and the box isn’t centered with the tie rods equal (completely ignoring the steering wheel), the your steering stops aren’t symmetrical. Which means go back to step #2, put the steering box in the middle of it’s travel and your tie rods won’t be equal.

The steering box is right, but the car may not be symmetrical. Remember suspension points on these cars have significant tolerances.

 

[chrismalish]

Thanks guys. I did just drive it for the first time in six weeks (and second time since I bought it and began "working" on a car that was "working" just fine). Drove great for an old car, and much improved from manual steering. Seemed to track just fine.

I may just take it to the alignment shop so they can put finishing touches on it if they can, then if it results in steering wheel cocked a bit, just reset it at the coupler.

New brakes work much better too.

I have had two alignment shops refuse to touch it out of hand ("we don't work on cars that old"); and another whose first opening is November 11(!). I have one more in mind that I might be able to sneak it into if I just show up and they think it is cool.

These pics do nothing to illustrate the problem or the solution but do prove I got it out of the garage, which made me happy.

 

[chrismalish]

Also 72Blu, you are correct in saying:

-the pitman arm has master splines that only allow 4 possible positions on the steering box (only one of which can be correct for this application)

-the steering coupler has no master splines at all

 

[Dave999]

its worthwhile scanning ebay for an alignment kit from the 70s one that uses wheel clamps that only go as big as 15 inch. i.e useless to most workshops these days because cars have bigger wheels

i picked up a set near where i live in the UK for £50
swivel plates
2 wheel clamps
2 long arms with protractors on the end and a long elastic to go between, woks great and avoids the usual beam of light and sight glass style of the old goodyear/Dunlop system which i could never fathom, the mirrors and light box are always too old to be effective.
and some camber castor gauges which i have not found time to work out yet



Churchill wheelforce TI 1900 equipment. no idea if they are british or american..

picture of a tiny Austin mini (not mine,) using the same set up. The rounded front of each arm has a swiveling protractor with a long pointer, that you can see through the window up near the black balance arm. join the two front swivels together with a long elastic and set track rods so that the pointer is a zero on each side. then a little tweak each side to add in required toe in. if you can find something like this you will never have to pay again. you can also stick them both on the same side facing each other to check how straight your wheels are, diff potentially has a slight toe in but its not a waste of time

 

[MoparLeo]

Everything must be as close to equal as possible. Mopars are notorius for bump steer issue going over hiily roads at speed.
The car will want to wander as it goes up and down during suspension travel. This because eneven tie rods will affect the toe-in and toe-out while driving.

 

[72bluNblu]

Everything must be as close to equal as possible. Mopars are notorius for bump steer issue going over hiily roads at speed.
The car will want to wander as it goes up and down during suspension travel. This because eneven tie rods will affect the toe-in and toe-out while driving.

First, Mopars are not "notorius" (sp) for bump steer. Compared to many other muscle cars they have less bump steer. For example, bump steer kits are everywhere for 60's and 70's Mustangs. You don't really see them for Mopars, Hotchkis is the only one that makes something that could be used that way and even they don't advertise it as a "bump steer kit". If it were a big problem you'd better believe someone would be selling a product for it and making a ton of money, because they're a pretty simple thing to make.

Toe change is just a fact of suspension geometry. It's always there. Better suspension designs have less and there is what's considered an acceptable amount (which most Mopars are usually close to or under), but toe change is never zero and making the tie rods perfectly equal doesn't change that. Toe change is generally considered to be acceptable if it’s less than 1/16” per inch of travel. So for the whole range of travel on these cars you’d be looking for less than ~.34” of toe change.

When Bill Reilly did the toe change measurements on an A body for the FMJ spindle swap he was getting less than .1” of toe change for the whole 5.5” range of travel he measured with A-body spindles and less than .2” of toe change with the FMJ spindles. You can see the results he plotted in this article. Either way, it shows A-bodies have pretty decent bump steer with what would be considered fairly normal suspension settings.

https://www.motortrend.com/articles/mopp-0503-swapping-a-and-b-disc-brake-spindles/

As for the uneven tie rods, yes, the length of the tie rod does have an effect on the bump steer, but you have to keep in mind that straight from the factory there is a significant amount of tolerance on the suspension mounts themselves, so depending on the car it may not be possible to have the tie rods equal lengths because the suspension mounts themselves may not be symmetrical.

 

[Demonx2]

First, Mopars are not "notorius" (sp) for bump steer. Compared to many other muscle cars they have less bump steer. For example, bump steer kits are everywhere for 60's and 70's Mustangs. You don't really see them for Mopars, Hotchkis is the only one that makes something that could be used that way and even they don't advertise it as a "bump steer kit". If it were a big problem you'd better believe someone would be selling a product for it and making a ton of money, because they're a pretty simple thing to make.

Toe change is just a fact of suspension geometry. It's always there. Better suspension designs have less and there is what's considered an acceptable amount (which most Mopars are usually close to or under), but toe change is never zero and making the tie rods perfectly equal doesn't change that. Toe change is generally considered to be acceptable if it’s less than 1/16” per inch of travel. So for the whole range of travel on these cars you’d be looking for less than ~.34” of toe change.

When Bill Reilly did the toe change measurements on an A body for the FMJ spindle swap he was getting less than .1” of toe change for the whole 5.5” range of travel he measured with A-body spindles and less than .2” of toe change with the FMJ spindles. You can see the results he plotted in this article. Either way, it shows A-bodies have pretty decent bump steer with what would be considered fairly normal suspension settings.

https://www.motortrend.com/articles/mopp-0503-swapping-a-and-b-disc-brake-spindles/

As for the uneven tie rods, yes, the length of the tie rod does have an effect on the bump steer, but you have to keep in mind that straight from the factory there is a significant amount of tolerance on the suspension mounts themselves, so depending on the car it may not be possible to have the tie rods equal lengths because the suspension mounts themselves may not be symmetrical.

I wasn't even after bump steer concerns as I worked to get my tie rod lengths close to equal. I was trying to prevent one wheel from turning in more than the other as the car lifts on the hit. Between getting them close and adding 3.5 deg of caster with the SPC double adjustable UCA's (using my Joe's Racing bubble gauge and my homemade alignment tools), I went from a car that I swore I would never go down the track with again to one that leaves and goes dead straight. Yippee!

Now if I could just cut me some better lights....