Rear end alignment issue 1969 cuda

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Mike69cuda

Mike69cuda

Mopar Moron
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Guys, one of my friends was following me and noticed my car was tracking crooked down the road. We looked at the rear wheels and noticed the front of the driver side rear wheel was about 1 inch closer to the front of the wheel opening than the passenger side.

I have been unable to figure out what is going on. Things I have tried so far:

1. I measured from where the front spring bracket attaches to the frame to the front of the spring perch on the 8 3/4 rearend. The measurement on the drivers side is one inch less than the passenger side, which makes sense with the wheel to fender measurement.

2. I took the u bolts loose on the driver side and confirmed that the the peg bolt in the springs was located in the hole in the spring perch on the rear end. Didn’t do the passenger side yet. The spring locating bolts / nuts that stick through the shock mounting plate on the bottom of the housing look centered to the axle housing.

3. I measured the forward spring mounting bracket to the torsion bar crossmember, they were within 1/4 inch. I also did an “x” measurement to determine if the torsion bar crossmember to the front spring mount was square. It was very close.

After all this it looks like the issue is that the center line of the rearend is one inch closer to the forward spring mount on the drivers side, although I don’t know which (or maybe both) are off.

The springs are different fron side to side. They are 6-7 leaf springs, I have attached pictures. I have read here that super stock springs are different from side to side, I don’t know if this is what I have. Could i have mismatched springs? The car was restored 10-15 years ago & looks like drivetrain was swapped out. I have had it about a year.

How could the springs be that far off, or am I missing something? Could difference in spring arches cause this?

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Assuming the hole in the perches are centered, and the front leaf spring perches are square to the body. The only way the rear axle could be 1 inch out would be leaf spring length from front CL mounting bolt to peg bolt.
 
Has the car been converted to disc brakes? The discs on the front will give the illusion of dog tracking due to the wider track on the front. There was a TSB on here that someone posted. The tire being closer to the wheel opening isn’t that uncommon either. There’s variances between the tolerances on these cars. Not saying you are or aren’t dog tracking just trying to throw info out there to help.

TSB mentioned here.
Disc brake conversion question
 
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Yeah, that has been done also. SSBC conversion kit done before I got it. Two different people have told me it tracks crooked. I suppose I should follow it myself to see. That is a good point, I have been assuming the problem is in the rear, not the front. However, I think the rear end is really off by an inch. I had a front end alignment done recently.
 
Dana67, that is the conclusion I have come to as well. I just want to be sure what is going on before I go to all the trouble of changing springs.

Could i shim the front spring bracket back to compensate?
 
Measurement was about 20 inches, but it is hard to make the catalog spring measurement with it installed. Eyeballing it one looked like 19.5 and one looked like 20.5.
 
One of our members had a diff that'd been shortened to A-Body.
His pass side wheel was toed in and thus forward by over 1/2 inch IIRC.
"String" the car, Google it, a quick, accurate trackside form of checking axle/wheel alignment.
Depending on the day of the week your car was put together, could determine how accurately it was assembled. Just saying. lol . Monday morn car ?
 
Mike69cuda said:
Dana67, that is the conclusion I have come to as well. I just want to be sure what is going on before I go to all the trouble of changing springs.

Could i shim the front spring bracket back to compensate?
Click to expand...
You can shim the front spring bracket but... make sure what is needed. Proper tracking has everything to do with relationship to the rotational planes, not the body.
You said you had a front end alignment. Did they not measure the rear? The thrust angle and rear toe need to be measured. Tracking by eyeball can be deceptive.
 
maybe measure with a plumb bob, and make marks on the concrete, which you can measure directly with a scale. Of course, you need to level the car up front to back , and left to right.
I suppose the rear axle housing could be bent. Probably a long shot. I once bought a 70 340 Cuda parts car, which the PO spun out and backed into power pole at speed. The 8-3/4 housing was bent, along with the driveshaft.
 
I had the alignment done at a little shop that my son knows the owner. They were old guys who still knew how to do it. I don’t think they checked the rear. The car actually drives good. The crooked thing bugs me, untreated perfectionist....
 
If you measured and it is off I would take it to a good alignment shop that can do a 4 wheel. You could also go to a body shop with a frame machine.
 
Just speculating at this point. The spring wraps around the front spring bushing. It should wrap around the bushing and almost touch itself. Is it unrolled compared left to right? (bigger gap) I've seen that a lot in collisions.
 
With all of the measurements that you've done, it does sound like the springs. There should be a part number on the top side of the main leaf. Check those to see what you have. Take video with your phone so that you don't have to take anything apart.
 
toolmanmike said:
You could also go to a body shop with a frame machine.
Click to expand...
^^^ There's measurements in the FSM to compare against.

Also beware of being fooled by optical illusion caused when following due to driver's position of following car and the front track being wider than the rear.

While we're suggesting possible causes, wheels with different offset.
 
Mike69cuda said:
Eyeballing it one looked like 19.5 and one looked like 20.5
Click to expand...
I think you have your answer. I would investigate the unrolled front eye of the spring as was suggested.
But my bet is the springs are just mismatched, luckly you would only have to replace one.
 
Check out the front eye bushings, is it my imagination or are they different?
For all the time it takes,I would drop the springs and place them side by side.
As to tracking, the car following has to be positioned such that the driver is dead-center on your car's centerline;otherwise parallax will mess him up.
Back in the 70's A-bodys were like Novas, lots of them were known as dog-trackers.
I agree with those who mentioned a thrust-angle alignment; the sensors will pick it up right away, and the tech will tell you where the issue lies.
 
I measured from the frame rail, where the spring perch mounts, back to the rear axle. I used the axle flange, because there were no brakes, But use a same point on both sides.
 
It was an inch on my car with SS springs , the Chrysler book says it should be 1/2 inch to allow for the different spring rates ,the passenger side is the torque side and compresses more under load , the 1/2 inch disappears and the car launchs straight .There are a number of threads on here regarding this factory offset . I made a spacer to correct mine to 1/2 inch .
 
AJ/FormS said:
Good point
Click to expand...
Mike69cuda said:
Guys, one of my friends was following me and noticed my car was tracking crooked down the road. We looked at the rear wheels and noticed the front of the driver side rear wheel was about 1 inch closer to the front of the wheel opening than the passenger side.

I have been unable to figure out what is going on. Things I have tried so far:

1. I measured from where the front spring bracket attaches to the frame to the front of the spring perch on the 8 3/4 rearend. The measurement on the drivers side is one inch less than the passenger side, which makes sense with the wheel to fender measurement.

2. I took the u bolts loose on the driver side and confirmed that the the peg bolt in the springs was located in the hole in the spring perch on the rear end. Didn’t do the passenger side yet. The spring locating bolts / nuts that stick through the shock mounting plate on the bottom of the housing look centered to the axle housing.

3. I measured the forward spring mounting bracket to the torsion bar crossmember, they were within 1/4 inch. I also did an “x” measurement to determine if the torsion bar crossmember to the front spring mount was square. It was very close.

After all this it looks like the issue is that the center line of the rearend is one inch closer to the forward spring mount on the drivers side, although I don’t know which (or maybe both) are off.

The springs are different fron side to side. They are 6-7 leaf springs, I have attached pictures. I have read here that super stock springs are different from side to side, I don’t know if this is what I have. Could i have mismatched springs? The car was restored 10-15 years ago & looks like drivetrain was swapped out. I have had it about a year.

How could the springs be that far off, or am I missing something? Could difference in spring arches cause this?

View attachment 1715238748

View attachment 1715238749

View attachment 1715238750
Click to expand...
I had the same problem on my b body,my front hangers were not the same.One was from a plymouth the other a dodge (about 1" difference)
 
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