Lean Question

[airbur]

If I place the front of the frame on jack stands, remove the tires, and let the axle down all the way (no support), would that release the pressure that would cause the lean from the radius arms?

 

[airbur]

In other words, if I level the frame in the front with stands, the rear tilt is even more exaggerated.....does that mean twisted frame?

 

[70_Steve]

If I place the front of the frame on jack stands, remove the tires, and let the axle down all the way (no support), would that release the pressure that would cause the lean from the radius arms?

In other words, if I level the frame in the front with stands, the rear tilt is even more exaggerated.....does that mean twisted frame?

The lean induced by the torque from uneven radius arms is created in the suspension only. It will not affect the frame at all.

Level the front of the frame with jackstands, such that you measure the same from the frame to the floor on each side of the frame. Then, at the rear of the frame, measure both sides to the floor. If the measurements at the rear of the frame are the same, the frame is straight. If the measurements are not the same, the frame has a twist. If the frame has a twist, a good frame shop should be able to fix it.

 

[airbur]

The lean induced by the torque from uneven radius arms is created in the suspension only. It will not affect the frame at all.

Level the front of the frame with jackstands, such that you measure the same from the frame to the floor on each side of the frame. Then, at the rear of the frame, measure both sides to the floor. If the measurements at the rear of the frame are the same, the frame is straight. If the measurements are not the same, the frame has a twist. If the frame has a twist, a good frame shop should be able to fix it.

Measurements are different...so I have a bent frame. Taking it in on Wed to a frame shop that can verify for sure. Thanks.

 

[airbur]

Update

Well, to update the question/thread...I took it to a good frame shop that measured the heck out of the frame and it's dead straight. So at this point I have completely removed the front axle to check the alignment of the radius arms....while I thought they may be off, in reality they are about 1/8 of an inch from each other.

Here's the kicker.....with the front axle out and the front of the frame on stands, the rear STILL has the lean. The front does not lean.

Rear frame to axle measurements are about 3/4" shorter on the driver's side.

Any suggestions? Should I try to adjust the driver's side radius arm up and over compensate for the lean on that side? I do notice that when it's on an incline....like on my driveway with the front pointed down, the rear's lean is even more exaggerated.

Also, the rear leafs (11 pack from WH)...I swapped them side to side and that made NO difference.

Tires are the same pressure.
All new bushings.
1" WH body lift with new mounts.
It does have a full AUX tank but I don't think that weight could cause this.
WH 2.5" suspension lift all around

I'm at the end of my rope Here are some pics although I know it's hard to see anything.

 

[DirtDonk]

It does have a full AUX tank but I don't think that weight could cause this.

Why not? It's weight.
Isn't that about 75 lbs or more? Try applying 75 lbs of upward force near the tank and see how high, if at all, the rear lifts.
I agree it's not likely to be responsible for the full 3/4" of drop, but that weight could conceivably have an effect of some kind.
Try sitting in it and having someone measure any additional drop there too, just to see how the springs are reacting to weight balance.
And all that could easily depend on the springs themselves I would think. Some springs have a pretty light initial resistance to moving from their static point.

When it comes right down to it too, if you just can't find the culprit, you can add a 3/4" shim to the driver's side rear. Easy, inexpensive, and it's what the factory might have done back then if they'd thought that the level was unacceptable.

Have you driven it much at all yet, just to see if anything shifts after the suspension has gone through some twists and turns?

Have you measured the spring perches themselves? Maybe one has crushed a little bit over the years? Not likely, but it happens.
And what about the spring hangers and shackles? Have you measured them for exact matching from side to side? Again, not likely to find 3/4" in there, but if there's a little in each area, it could add up.

What about just adding a second battery to the right front? I know that sounds silly at first blush, but if you've ever thought of doing that, now's the time. Just in case there's a slight weight imbalance (there's probably a lot of that going on in a Bronco!) and this leveraged weight can help even a slight amount.

that's about it for now. Just some stuff food for thought.

Paul

 

[DirtDonk]

Have you measured your body cushions and mounts? The body-to-bumper clearance looks off from side to side.
Since you're measuring clearance at the axles, I'll assume this has nothing to do with your concerns, but it would certainly add to the visual problem, making that 3/4" at the axle, look like a bunch at the fenders.
Of course, all sorts of things give you visual problems with a Bronco. Fender flares not even, body not even, body mounts not even, bumpers not straight, all that stuff. Even Ford used shims under certain mounts to even things out on the production line, so it's something that certainly comes up.

Paul

 

[airbur]

Why not? It's weight.
Isn't that about 75 lbs or more? Try applying 75 lbs of upward force near the tank and see how high, if at all, the rear lifts.
I agree it's not likely to be responsible for the full 3/4" of drop, but that weight could conceivably have an effect of some kind.
Try sitting in it and having someone measure any additional drop there too, just to see how the springs are reacting to weight balance.
And all that could easily depend on the springs themselves I would think. Some springs have a pretty light initial resistance to moving from their static point.

When it comes right down to it too, if you just can't find the culprit, you can add a 3/4" shim to the driver's side rear. Easy, inexpensive, and it's what the factory might have done back then if they'd thought that the level was unacceptable.

Have you driven it much at all yet, just to see if anything shifts after the suspension has gone through some twists and turns?

Have you measured the spring perches themselves? Maybe one has crushed a little bit over the years? Not likely, but it happens.
And what about the spring hangers and shackles? Have you measured them for exact matching from side to side? Again, not likely to find 3/4" in there, but if there's a little in each area, it could add up.

What about just adding a second battery to the right front? I know that sounds silly at first blush, but if you've ever thought of doing that, now's the time. Just in case there's a slight weight imbalance (there's probably a lot of that going on in a Bronco!) and this leveraged weight can help even a slight amount.

that's about it for now. Just some stuff food for thought.

Paul

Thanks for the insight Paul. I've driven it quite a bit over the last 6 months and I think any evening-out has already happened. Spring hangers and shackles are all the same.

I will run the aux tank down to almost empty and see if that changes anything. 2nd battery is a good idea but I'm not quite there yet and don't want to add one if not necessary. Body cushions and mounts are all correct. The bumper to body gap is about the same all the way around.

I imagine I'll re-adjust the radius arms to compensate a bit and re-install the front axle as it's obvious that's not the issue now.

Thanks again.

 

[airbur]

Something just hit me....with the front frame up on jackstands as it sits now, I don't think the aux tank would come into play at all to cause the lean. That make sense? If it were down on the floor with all 4 corners of the suspension engaged, then yes...that extra weight might do something.

That's why I'm thinking it's not the AUX tank.

I just had my 109lb wife sit in the passenger seat...then she got out with me watching the lean from the rear....zero difference.

 

[DirtDonk]

Something just hit me too. You're right!;D
Or at least, you're most likely right. At the very least, it would change just how much effect the added weight would have, if not exactly eliminating it.
Good call.

Paul

 

[DirtDonk]

Turn your Bronco upside down and see which wheel is the lowest. Then add extra weight to the others until they match.
Problem solved!

Paul

 

[airbur]

Turn your Bronco upside down and see which wheel is the highest. Then add extra weight to the others until they match.
Problem solved! Paul

Man...why didn't you suggest that earlier?! Would have saved me sooo much time

 

[DirtDonk]

I just wasn't thinking clearly until now. Well, I wasn't thinking clearly just then either. I should have said "lowest" tire (since corrected) instead.
Live and learn.

Oh, and be sure to let us know how it works out. ;D

Paul

PS: If that doesn't do the trick, just sandblast it! That'll fix anything.

 

[akafrankcastle]

Both of my Broncos have suffered from the dreaded lean. The '66 lacked an auxiliary tank, power steering box, and any other driver's side mounted dodads you might imagine would cause the truck to drop on that side. When I picked it up from the PO, it didn't have the lean. Why? The PO had modified the lift blocks used under the rear springs by cutting one down by about 3/4-1" to compensate for this.

I think the best thing you can do to compensate for the lean, if it really bothers you (which I suspect it might seeing as you pulled the front axle!) is to plan your upgrades appropriately to incorporate the passenger side. Location of hi-lift jack mounting, tool box mounting, etc. can add a bit of weight to the passenger side, resulting is a bit of sag and evening things up. Otherwise, I think you're going to wind up going mad trying to solve the mystery of why your well built, well equipped rig appears to have balance issues.

And you know, it could be something very small and inconspicuous that you simply cannot see. Imagine a mattress that has only ever been slept on by one person. There will be a noticeable impression. 40 years of drivers entering, exiting, and driving the truck could have caused slight alignment issues in the mounting points for the suspension. (Imagine a magazine for a weapon only ever being loaded with one round at a time before being fired. Eventually, there will be a slight difference in spring tension.) This repeated use over years might not have caused a shift in the vertical position of your suspension mounting points, but could have caused a horizontal shift (springs hangers shifting 1/8" to the outside of the frame, etc.). These small horizontal shifts could potentially result in a difference in vertical height, I suppose.

But, I'm no engineer.

 

[DirtDonk]

Ahhh, but you could be, grasshoppa. You could be...

Paul

 

[airbur]

.....if it really bothers you (which I suspect it might seeing as you pulled the front axle!).....

That's the thing...it REALLY bothers me. So much so that when I drive it, I feel like I'm on an inclined race track....I know it's all mental....but I can't stand it.

I think my best bet is to go with your idea of future upgrades on the pass side and also consider a 3/4" block under the driver's side leaf spring.

Thanks for all the help (and philosophy) guys....much appreciated! Now who is going to re-install this axle???!!

 

[akafrankcastle]

Now who is going to re-install this axle???!!

Dana 44? I'll do it. Or were you wanting it reinstalled on your truck?

As far as the future upgrades go, I've been planning this myself for some time now. I'm a HUGE prick when it comes to weight distribution, economy of space, and maximizing my load. So much so that when it comes to loading out for a deployment, the guys I work with don't even bother to put anything in to the containers. They simply drop it off outside and let me deal with it.

I think it you play it smart, and anal retentive, with the location and placement of those accessories you install in the future, you'll see this thing level out and be much happier. If that doesn't work, just hack off those spring hangers and mount them 3/4" lower.

 

[airbur]

Anyone have shim vendor suggestions? I'd like to have ones that are designed for the Bronco and don't need to be modified. Thanks.

 

[70_Steve]

OK, so never mind what the frame shop said. While you've still got the front on jack stands, measure from each side of the frame, right next to the jack stands, down to the floor. Then measure from each side of the rear of the frame, just in front of the rear bumper, to the floor.

I suspect that you will have the same measurements from each side in the front, since both sides are on jack stands and the jack stands appear to be set up the same.

If the front measurements are the same, but the rear measurements are not, then the frame is twisted.

 

[airbur]

OK, so never mind what the frame shop said. While you've still got the front on jack stands, measure from each side of the frame, right next to the jack stands, down to the floor. Then measure from each side of the rear of the frame, just in front of the rear bumper, to the floor.

I suspect that you will have the same measurements from each side in the front, since both sides are on jack stands and the jack stands appear to be set up the same.

If the front measurements are the same, but the rear measurements are not, then the frame is twisted.

Yep, the measurements are different in the rear. Would a frame shop not check for "twist" unless specifically asked?