1971 Demon Strange steering problem

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Juan Correa said:
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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There's no reason to toss what you have, and you will not get better geometry with a coil over set up and rack and pinion. This is likely a simple installation problem that can be easily fixed once it's located.

I seriously doubt this is some kind of inherent geometry issue as my own car runs about half of the parts you have, runs a more aggressive alignment and wheels, and has none of the issues you describe. The scrub radius is not likely the issue, because for this issue to be coming from the scrub radius the force would literally have to be working against the torsion bars to compress the suspension. Even if you have stock torsion bars that would mean ~200 lbs of force to cause a 2" drop. That's not coming from the scrub radius. More than likely there is an issue with the ride height adjustment itself, because that's the only way the 2" drop isn't working against the torsion bar resistance.

If you really want to get rid of something, get rid of the drop spindles. They're not necessary at all at the ride height your car is sitting at in the pictures above. And even if you wanted to lower the car 2", you can do that with the stock spindles by using larger torsion bar diameters and just lowering with the torsion bar adjusters. It does require a little re-working of the bump stops, but that's really minor. I've lowered my car 1 7/8" with factory spindles and 1.12" torsion bars (so the LCA is in fact parallel to the ground and the difference in height between the LCA pivot and lower ball joint is 0)

Do you even have stock torsion bars installed? Or something else?
 
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Another thing I have seen is when almost any part in the steering system is NOT rigidly fixed; as in any item that can allow the steering on one side of the car, to move out of synchronicity with the other. I took it for granted by your statements, that this was NOT happening.
Like if,
the centerlink is NOT held in it's place, say by the idler arm flexing
Or the Tie-rod connecting tubes are loose,
or the UCAs are moving in the saddles.
or the steering box is not fixed.

But the pivoting force has to exist prior to that, and the only force I know of, with the wheels steered ahead and the suspension not cycling, that can do that is Scrub radius.
Excessive; caster/SAI/LCA angle, or broken/missing shocks; can make it worse.
here is a link;
Scrub radius - Wikipedia
What Is Scrub Radius And Why Is It Important?
 
72bluNblu said:
There's no reason to toss what you have, and you will not get better geometry with a coil over set up and rack and pinion. This is likely a simple installation problem that can be easily fixed once it's located.

I seriously doubt this is some kind of inherent geometry issue as my own car runs about half of the parts you have, runs a more aggressive alignment and wheels, and has none of the issues you describe. The scrub radius is not likely the issue, because for this issue to be coming from the scrub radius the force would literally have to be working against the torsion bars to compress the suspension. Even if you have stock torsion bars that would mean ~200 lbs of force to cause a 2" drop. That's not coming from the scrub radius. More than likely there is an issue with the ride height adjustment itself, because that's the only way the 2" drop isn't working against the torsion bar resistance.

If you really want to get rid of something, get rid of the drop spindles. They're not necessary at all at the ride height your car is sitting at in the pictures above. And even if you wanted to lower the car 2", you can do that with the stock spindles by using larger torsion bar diameters and just lowering with the torsion bar adjusters. It does require a little re-working of the bump stops, but that's really minor. I've lowered my car 1 7/8" with factory spindles and 1.12" torsion bars (so the LCA is in fact parallel to the ground and the difference in height between the LCA pivot and lower ball joint is 0)

Do you even have stock torsion bars installed? Or something else?
Click to expand...

i have the stock ones right now, i had the 1,12 ones but they are to stiff for my taste.

ill take pics and videos tomorrow and post them
 
Sounds like a strut rod problem, caster is really high too. I would back it off to 3 degrees. Make sure the strut rods are the correct size. I got a shipment from Hotchkis and the part number on the box was correct but the rods inside were too long.
 
well it looks like the problem was the ball joint arms “ custom built” were installen on the wrong sode of the drag link! ill keep you posted
 
Juan Correa said:
well it looks like the problem was the ball joint arms “ custom built” were installen on the wrong sode of the drag link! ill keep you posted
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OK you need to check this out very carefully. What you just said makes no sense. It is common on disk brake cars to reverse the spindles side to side, which puts the brake calipers on the rear of the spindles instead of the front. If you are talking about the pointed ends (tapered studs) where 4 fittings go through the center link---THAT SETUP CHANGED in 73. 67--72 drag link is DIFFERENT than 73 and later, and the idler arm and pitman arm are also different. You can interchange them AS A GROUP. But they all must "group" in the same years range

This is 67--72. NOTICE that the idler arm and pitman arm studs point UP

old-jpg-jpg.jpg


Below, this is the 73/ later setup. Notice that the idler arm and pitman arm studs point DOWN

new-jpg-jpg.jpg
 
the thing is that my tie rods are made eith Hiem joint, so I can put them in the front or back of the drag link ( drag link has no cone any more on the ends)
 
ultimatejay said:
Sounds like a strut rod problem, caster is really high too. I would back it off to 3 degrees. Make sure the strut rods are the correct size. I got a shipment from Hotchkis and the part number on the box was correct but the rods inside were too long.
Click to expand...

Caster isn’t that high. I run more than that at +6.5*. That’s not the problem.

Juan Correa said:
well it looks like the problem was the ball joint arms “ custom built” were installen on the wrong sode of the drag link! ill keep you posted
Click to expand...

Wait, are you saying they pointed the lower ball joints so the steering arms are to the front? So it was set up to front steer?
 
72bluNblu said:
Caster isn’t that high. I run more than that at +6.5*. That’s not the problem.



Wait, are you saying they pointed the lower ball joints so the steering arms are to the front? So it was set up to front steer?
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sorry for al the confusion! ill post pics in a few
 
Can't tell anything by those terrible pics but one things for sure you need to ditch those heim joints and use factory tie rods inner and outer and factory lenght adjustment rods. Why is he using heim joints for the inners?
 
ultimatejay said:
Can't tell anything by those terrible pics but one things for sure you need to ditch those heim joints and use factory tie rods inner and outer and factory lenght adjustment rods. Why is he using heim joints for the inners?
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ill try to get better pics today, the heime joins came in a bump steer correction kit we are using
 
Juan Correa said:
ill try to get better pics today, the heime joins came in a bump steer correction kit we are using
Click to expand...
Like I said, throw that bump steer kit in the trash can and put an original drag link, inner and outer tie rod and adjustment rod, idler arm and pitman arm and you will be perfect. Qa1 made those upper and lower arms to work with factory parts. I'm not aware of these cars every having issues with bump steer unless you use aftermarket parts and change the geometry. In fact when I bought my 70 Duster it had worn out suspension and steering and it still tracked straight and never had bump steer.
 
ultimatejay said:
Like I said, throw that bump steer kit in the trash can and put an original drag link, inner and outer tie rod and adjustment rod, idler arm and pitman arm and you will be perfect. Qa1 made those upper and lower arms to work with factory parts. I'm not aware of these cars every having issues with bump steer unless you use aftermarket parts and change the geometry. In fact when I bought my 70 Duster it had worn out suspension and steering and it still tracked straight and never had bump steer.
Click to expand...
we made all these mods because the car developed horrible bump steer ill send you a pic with all the qa1 and stock parts
 
Juan Correa said:
we made all these mods because the car developed horrible bump steer ill send you a pic with all the qa1 and stock parts
Click to expand...
Ok, then there is something wrong with the parts you put on or they were put on incorrectly. Theres thousands of cars on the road with Qa1 upper and lower arms with stock steering with no problems
 
If you're not aligning the car with slip/turn plates under the front tires, you will end up with way to much toe and that will cause what you describe.
 
ok guys, so we removed the unnecessary mods, and it looks like it’s working!! ill take it for alignment tomorro and take it for a ride and let you know. thank you all so much for the help and ideas
 
are you sure you didn't just need to jounce it bounce it and run it back and forth a few times between each adjustment.
if the tyres can't move In out or left and right as you make the big changes that you need to make as you set it up into good ballpark before you start your tacking and alignment everything is all over the place and you just fight friction between tyre and floor.
this is usually to do with wildy wrong toe in/out
roll a car back and forth in this state and you get the same symptoms
1 tyre patch rolled 1 way the other fighting it, wheels splayed front of car rises or lowers as you move back and forth.

it needs to be a ride height first, then it needs to be ball park driveable and going straight before you start with the alignment guages and messing with camber and castor.

if you put back the standard less adjustabe stuff and it now works the standard setup and the toe in or out you ended up with may well have just been closer to correct.

there may have been nothing wrong with the aftermarket set up you had...just you had not moved the car enough when setting it up. when you thought it was right your tyre contact patch was twisted and fighting your last adjustment


[AH already been said......] I'll read everything next time :)
Dave
 
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