1971 Demon Strange steering problem

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J

Juan Correa

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Hi guys

I have a 71 dodge demon, qa1 k member, qa1 upper and lower arms, magnumforce lower spindels.

i sent the car’s suspension: -.5 camber, 5 caster, 1/8” toe. and as soon as i woll the car forwad the wheels toe out and de cars nose drops 2”, revers and it goes back to normal.

upper arms are tight, tierods are tight and new. Iam super stomped!!!

71C34435-9902-4566-8777-95BC90603BA1.jpeg
 
Random thought, but........

If you reinstall all the stock parts, does the problem go away?
 
AJ/FormS said:
Yur toe is NOT what you think, remeasure it. It may b 1/8 toe out!
If that don't find it, your scrub radius may be too great.

Super nice looking ride!
Click to expand...

hi, well it i leave it toe out the car starts too raise a looot!
 
When you set the ride height of the car did you roll it forward or back at all? If you change the ride height you have to roll the car so it reaches its new height.

The same goes for raising or lowering the car with a jack. If jack the car up and then set it down, you need to roll it forward or back for the suspension to fully settle. Bouncing or jouncing the front end will not fully settle it.
 
72bluNblu said:
When you set the ride height of the car did you roll it forward or back at all? If you change the ride height you have to roll the car so it reaches its new height.

The same goes for raising or lowering the car with a jack. If jack the car up and then set it down, you need to roll it forward or back for the suspension to fully settle. Bouncing or jouncing the front end will not fully settle it.
Click to expand...

yes we rolled the car to adjust ride hight. I think its a toe problem…. but i don’t know
 
72bluNblu said:
Wouldn’t matter for this unless he installed it after he set the alignment and the height changed.




What are you using to set the alignment and toe?
Click to expand...

we are using a tape to be able to get it to the alignment place, i know its not accurate but its just to get it rollong 6 blocks.

If its just a bit off will it do this? its my first mopar and this is sooooo frustrating!!!
 
Just curious... with QA1 k-member and control arms, why do you have MagnumForce lowering spindles? Why not QA1 spindles? The car doesn't appear to be lowered.

Is this a coilover conversion or do you still have the torsion bars. If torsion bars, are the strut rods installed?

Do you have pictures of the suspension?

Could you have it hauled or towed to alignment shop? Maybe they could find the problem.
 
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Poly lower bushings? Adjustable struts? Something is moving. Mine did the same thing. I Put all factory parts and bushings back in.

One car We recently had here the idler hole was wore and moving on the K-member. It could be many things that only hands on will find. But don't thing all those new parts are correct just because they are new.
 
Juan Correa said:
we are using a tape to be able to get it to the alignment place, i know its not accurate but its just to get it rollong 6 blocks.

If its just a bit off will it do this? its my first mopar and this is sooooo frustrating!!!
Click to expand...

No, the toe being “just a bit off” will not cause the ride height to change 2” when the car is moved.

tinman2 said:
Just curious... with QA1 k-member and control arms, why do you have MagnumForce lowering spindles? Why not QA1 spindles? The car doesn't appear to be lowered.

Is this a coilover conversion or do you still have the torsion bars. If torsion bars, are the strut rods installed?

Do you have pictures of the suspension?

Could you have it hauled or towed to alignment shop? Maybe they could find the problem.
Click to expand...

QA1 doesn’t make drop spindles.
 
QA1 doesn’t make drop spindles.[/QUOTE said:
My point was "why dropped spindles" because the car doesn't appear to be lowered. So with dropped spindles, the suspension must be jacked up to sit like in the picture.
Click to expand...
 
tinman2 said:
My point was "why dropped spindles" because the car doesn't appear to be lowered. So with dropped spindles, the suspension must be jacked up to sit like in the picture.
Click to expand...

Clearly there’s still a lot we don’t know about what the OP is after or how the suspension has been assembled.

As a rule, drop spindles are completely unnecessary on these cars. But they’re not likely causing his issue either.
 
Juan, hopefully these guys can help you with your suspension problem.

You have a very nice looking Demon!! I bet you get a lot of looks in Columbia!!
 
I was looking at current QA1suspension on their website and I was just wondering if this is new parts or pieced together odds and ends. Is it front mounted rack & pinion or factory style steering? I have seen a picture of what looked like a modified factory lower control arm with a QA1 sticker on it. Some good pictures couldn't hurt.
 
hello guys, I will try to tow it to an alignment shop and see there.

Ill get you some pictures of the suspension on monday, but its still torsion bars with 2 way adjust qa1 struts.

I agree something’s moving! but cant figure out what, i did stand near the car as it rolled but all i can se is the wheels tow out and the car start to drop
 
Juan Correa said:
i sent the car’s suspension: -.5 camber, 5 caster, 1/8” toe. and as soon as i woll the car forwad the wheels toe out and de cars nose drops 2”, revers and it goes back to normal.
Click to expand...
I think this is real simple; but the cure is not cheap.
I think it could be a combination of too much scrub radius and the lower control arms not set parallel to the ground-plane. Here's my thought;
the scrub radius is causing the tire to pivot and drive away from the centerline of the car. The effective length of the Lower control arm changes, allowing the camber to change, which allows the wheels to toe out, and all this monkey-motion cause the ride-height to change..
I have seen this several times with the powertrain out; when there is no weight to prevent the tiny force generated by the scrub radius to resist this action. Once the engine went in, this action seemed to quit, but that scrub radius problem was still there and could now be felt while driving, as a nervous twitch, and a wander. The only cure was to restore the scrub radius back as close to zero as possible.
If you don't know it, scrub radius is a point in the tires contact patch, created by an imaginary line drawn thru the upper and lower BJs, down to the floor; relative to the centerline of the tire, at the floor.

In the factory suspension engineering, this point is very close to zero, when:
the lower control arm is parallel to the ground,and
the camber is close to zero, and
the wheels have a Zero offset, and
the tire is of a specified height.
Changing any one of those changes the scrub-radius.
You have, I think, changed them all.
 
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67Dart273 said:
Come up here and do that to mine, will ya?
Click to expand...
sure!
AJ/FormS said:
I think this is real simple; but the cure is not cheap.
I think it could be a combination of too much scrub radius and the lower control arms not set parallel to the ground-plane. Here's my thought;
the scrub radius is causing the tire to pivot and drive away from the centerline of the car. The effective length of the Lower control arm changes, allowing the camber to change, which allows the wheels to toe out, and all this monkey-motion cause the ride-height to change..
I have seen this several times with the powertrain out; when there is no weight to prevent the tiny force generated by the scrub radius to resist this action. Once the engine went in, this action seemed to quit, but that scrub radius problem was still there and could now be felt while driving, as a nervous twitch, and a wander. The only cure was to restore the scrub radius back as close to zero as possible.
If you don't know it, scrub radius is a point in the tires contact patch, created by an imaginary line drawn thru the upper and lower BJs, down to the floor; relative to the centerline of the tire, at the floor.

In the factory suspension engineering, this point is very close to zero, when
the lower control arm is parallel to the ground,and
the camber is close to zero, and
the wheels have a Zero offset, and
the tire is of a specified height.
Changing any one of those changes the scrub-radius.
You have, I think, changed them all.
Click to expand...
ok perfect ill see on monday and see that! thankx
 
AJ/FormS said:
I think this is real simple; but the cure is not cheap.
I think it could be a combination of too much scrub radius and the lower control arms not set parallel to the ground-plane. Here's my thought;
the scrub radius is causing the tire to pivot and drive away from the centerline of the car. The effective length of the Lower control arm changes, allowing the camber to change, which allows the wheels to toe out, and all this monkey-motion cause the ride-height to change..
I have seen this several times with the powertrain out; when there is no weight to prevent the tiny force generated by the scrub radius to resist this action. Once the engine went in, this action seemed to quit, but that scrub radius problem was still there and could now be felt while driving, as a nervous twitch, and a wander. The only cure was to restore the scrub radius back as close to zero as possible.
If you don't know it, scrub radius is a point in the tires contact patch, created by an imaginary line drawn thru the upper and lower BJs, down to the floor; relative to the centerline of the tire, at the floor.

In the factory suspension engineering, this point is very close to zero, when:
the lower control arm is parallel to the ground,and
the camber is close to zero, and
the wheels have a Zero offset, and
the tire is of a specified height.
Changing any one of those changes the scrub-radius.
You have, I think, changed them all.
Click to expand...

I simply don’t buy this at all.

First, in the factory geometry the lower control arms are not parallel to the ground. The difference in height between the LCA pivot and the lower ball joint is 1-7/8”, for the LCA to be parallel that number would be 0. While it’s hard to tell from just a picture, it doesn’t appear to me that the OP’s car is higher than factory. With the drop spindles that could be changing the lower control arm angle up from stock, as he doesn’t look 2” lowered, but I’ve run drop spindles without that issue.

Second, the ride height change he’s describing is 2”. Even if there was some validity to that scrub radius effect as you’re describing it, that change would be no where near 2”. The toe change required to do that would be massive. More likely the change in toe is following the change in ride height (not the other way around like you're describing), as the car lowers the LCA's get closer to parallel to the ground, making them effectively longer and because the tie rods stay the same length the rear steer set up causes the wheels toe out.

And finally, I run the same QA1 LCA’s, high offset wheels, more negative camber and more positive caster than the OP does without anything like the issues you describe.
 
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72bluNblu said:
I simply don’t buy this at all.

First, in the factory geometry the lower control arms are not parallel to the ground. The difference in height between the LCA pivot and the lower ball joint is 1-7/8”, for the LCA to be parallel that number would be 0. While it’s hard to tell from just a picture, it doesn’t appear to me that the OP’s car is higher than factory. With the drop spindles that could be changing the lower control arm angle up from stock, as he doesn’t look 2” lowered, but I’ve run drop spindles without that issue.

Second, the ride height change he’s describing is 2”. Even if there was some validity to that scrub radius effect as you’re describing it, that change would be no where near 2”. The toe change required to do that would be massive. More likely the change in toe is following the change in ride height (not the other way around like you're describing), as the car lowers the LCA's get closer to parallel to the ground, making them effectively longer and because the tie rods stay the same length the rear steer set up causes the wheels toe out.

And finally, I run the same QA1 LCA’s, high offset wheels, more negative camber and more positive caster than the OP does without anything like the issues you describe.
Click to expand...

ill get lots ok picture’s tomorrow, there are a lot of mods done to the front, Iam not the mecanic on the suspension part, its a friend form a shop. he does custom frames there and he’s stopped too, but if all else fails i’ll toss the torsion bars an lca and do a coilover setup with rack an pinion
 
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