My rear end alignment issues, All fixed! Options

[PanelBilly]

When I originally went in for my alignment I discovered that the rear wheels were toed out and there wasn't any adjustment left in the trailing arms. You can see by the photo,
the arm is nearly up against the frame and it was still toe out -75.



So he fix was going to be modifying the outer mount, so the holes were made larger. Here is a mount before and after.



That helped it move a tiny bit closer, but being that it was already so close to the frame before, moving it right against the frame was all that I could do.

So off came the trailing arm again and it went to the machine shop where I had my engine work done. We bolted it up to the mill and rigged it so it was plumb.



Now we could check the angle of the hub to see what it measured. Should be 12.5, but it was 13.



Now I didn't take a photo of the jig we set up, but using a press and several pieces of steel, we warped the arm so that it was 12.5.

Back to the alignment shop to see if it worked. Now the toe was only out a tiny bit. So I pulled the arms off again and on Saturday we bent them a little more. Tomorrow I go in
for what I hope is the final alignment. My trailing arms had been reinforced with three tubes so I think they could hold up to a bit more stress that an OEM.

[r_towle]

Are those stock trailing arms or did you modify them?

[tomrev]

Are those stock trailing arms or did you modify them?

They were modded by drilling and welding the tubes passing thru, and triangulating the arm. I was wondering when looking at the photo how accurate it would be to measure the hub, without the CV spline bolted tight to load the wheel bearing in the arm. Seems my hubs have always been pretty lousy-goosy when not loaded with the axle/CV assembly bolted and torqued.

[rgalla9146]

Were your inner ears replaced ?
Others here have modified their trailing arms like you did.
Did their arms change shape ?
It might be more effective to slightly move the hole in the inner ear by filing and welding.
I agree that you should have the hub/stub tight.

[PanelBilly]

Inner ears were not replaced

[JFJ914]

When I had that same problem it was a bent arm.

[PanelBilly]

Everything worked out perfect. The car tracks down the road great. Shows that if you don't give up, you eventually figure it out

[ThePaintedMan]

So Billy, given that they were both tweaked, are you guys thinking it was related to the welding done to stiffen the arms?

[Evil Older Brother]

Billy,

Hope all goes well with the proctologist on your "anal"iment..............

[Evil Older Brother]

Billy,

Hope all goes well with the proctologist on your "anal"iment..............

[Elliot Cannon]

So Billy, given that they were both tweaked, are you guys thinking it was related to the welding done to stiffen the arms?

That was my exact thinking. The welding could have warped the trailing arm. Some of my most careful measuring has gone straight to hell after the welded metal cools. (IMG:style_emoticons/default/welder.gif) (IMG:style_emoticons/default/headbang.gif) (IMG:style_emoticons/default/lol-2.gif)

[914_teener]

I have seen this done a couple of different ways.

In my opinion this (rods or tubes) is the only way to really strengthen the trailing arm most effectively.

The add on "box kits" do not approach this method in strengthening the section.

When you weld an assembly like this, the weld shrinkage is in the KIP range of force.

Tons of force in other words. So HOW it is welded is everything to keeping the right angles on the arms.

[76-914]

I have seen this done a couple of different ways.

In my opinion this (rods or tubes) is the only way to really strengthen the trailing arm most effectively.

The add on "box kits" do not approach this method in strengthening the section.

When you weld an assembly like this, the weld shrinkage is in the KIP range of force.

Tons of force in other words. So HOW it is welded is everything to keeping the right angles on the arms.

Good info. Wouldn't pre-heating the arm first alleviate the warping?

[mgp4591]

Were your inner ears replaced ?
Others here have modified their trailing arms like you did.
Did their arms change shape ?
It might be more effective to slightly move the hole in the inner ear by filing and welding.
I agree that you should have the hub/stub tight.

Did you drill and pass the tubes straight through or did you drill and pass at angles? I've seen examples of both and wondered which would work better - I'd bet angles would bear the stresses better. Then comes the question of whether Jamie would have bent his ears when he hit the rail rather than just needing to replace the arm??

[ThePaintedMan]

Or using a jig and distributing the welds evenly an minimizing heat.

[914_teener]

I have seen this done a couple of different ways.

In my opinion this (rods or tubes) is the only way to really strengthen the trailing arm most effectively.

The add on "box kits" do not approach this method in strengthening the section.

When you weld an assembly like this, the weld shrinkage is in the KIP range of force.

Tons of force in other words. So HOW it is welded is everything to keeping the right angles on the arms.

Good info. Wouldn't pre-heating the arm first alleviate the warping?

No....best way is to index the part and fixture it then strategically weld it so that the forces will counteract each other and then mechanically post relieve it if necessary. If done right no post relief would be necessary.

[914_teener]

Were your inner ears replaced ?
Others here have modified their trailing arms like you did.
Did their arms change shape ?
It might be more effective to slightly move the hole in the inner ear by filing and welding.
I agree that you should have the hub/stub tight.

Did you drill and pass the tubes straight through or did you drill and pass at angles? I've seen examples of both and wondered which would work better - I'd bet angles would bear the stresses better. Then comes the question of whether Jamie would have bent his ears when he hit the rail rather than just needing to replace the arm??

Angles. Yes......probably not the best or maybe not needed for a stock four street car. But....I also think that these weldments have stress relieved after the decades and have lost their original spec.

[PanelBilly]

Tubes are not angled. Someone else did the welding The workmanship looks professional I just happy that I knew someone who could bend them and the task is over. I got real fast at removal and installation

[tygaboy]

Great result but I'm curious:
How EXACTLY did you bend the arms back into spec. What "bent" during the correction?
Pics of the "bending jig"?