Instability Question

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Dust1

Dust1

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I recently replaced all suspension components on my 71 Duster and got a front end alignment from a reputable shop in the area. I have a serious issue. Whenever I hit a rise in the road, go over a bump or a bridge the car gets real unstable and wants to veer to the right ditch! It is very dangerous and with the 440 Super Commando very fast making it very deadly. What could be causing this instability? Thanks for any knowledge on this issue.
 
................Post ur align specs................probably more than 1 spec out of wack.......well get u on the right track.......................kim..........
 
Get the front end jacked up and check your torsion bars.Look at them front to back it sounds like one of them may be loose.This usually happens right around the lower control arm.Its easy for it to get wallowed out and that will make the car do what you are desribing
 
Since it happens on a rise in the road when your suspension is unloading I would jack the front end up and see if anything goes into a bind in the steering. Does your steering go between the header pipes? Maybe they touch when your tie rod ends move down with your spindles? Just a couple thoughts.....
 
It really is not likely that the alignment is not correct. I got the very best shop in the area to do it. They are good. They told me to bring it back and they will check it out. I forgot to mention I replaced all steering components too, except pitman and idler arms. All new. Hooker fenderwells. I will jack it up and recheck everything and the torsion bars at the lca's. You are correct michformulaS. It only happens on the rise.
 
Dust1 said:
It really is not likely that the alignment is not correct. I got the very best shop in the area to do it. They are good. They told me to bring it back and they will check it out. I forgot to mention I replaced all steering components too, except pitman and idler arms. All new. Hooker fenderwells. I will jack it up and recheck everything and the torsion bars at the lca's. You are correct michformulaS. It only happens on the rise.
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They can be the best in the country, but if they are using the wrong spec's, it will drive like $h!t.

Most shops try and use the spec's that these cars were designed for back in the day, the problem is the roads are not built the same as they were back then and the original spec's are set up with different numbers for both sides to accommodate the extreme crowns that use to be put in the roads back then. Both sides should be the same for the roads we drive on today and you should have more caster than they originally called for and less camber (if any).
 
Y ou have a very valid point there Blownfish. I will take it back to the alignment shop with my concerns. Thanks all!
 
You didn't replace idler and pittman arms? Why not? A very small amount of wear can cause all sorts of slop and bump steer.

The Mopar chassis book has some great info on bump steer and how to get rid of it.
 
We have had MANY people on here take their car to the "VERY BEST" alignment shop and end up with a bad alignment.

This is often related to the alignment shop using the factory alignment specs (designed around a bias ply tire).


Oh… And what Blownfish said (I just saw his post).
 
placing my quarter bet on worn out idler arm. if you told them you replaced everything they wouldn't have checked anything. Good luck
 
..............Also the K frame wears badly where the lower control bolts thru.......post ur specs, so we can help u out b4 u take it back again and again, u say u want help , so let us help u....lots of times ppl ask questions then dont listen anyways, dont b1 of them......kim........
 
Always replace the pitman and idler when you rebuild the front end the parts are cheap and you cant aling the car if either are even close to worn.When you have the car jacked up pull on the idler arm if the suspension moves at all its shot.If your k-frame or lower control arms are wallowed out you can just weld them up,I have done this before and never had a problem again.
 
I have aften wondered how alignment shops can do alignment on muscle cars with fatties on the back and skinnies on the front using factory specs?

Do they have a general set up for these types of cars with lotsa mods and different sized wheels?

I really, really lucked out and did my own alignment in my garage using my eyeballs and measuring tape.
My car tracks straight and the tires are not showing any strange wear.
I guess I lucked out, but I used to do alignments at the dealership on factory cars only.

I would like to know where to go so I can get my car professionally dialed in.
 
I found a guy that can do the alignment to the specs I wanted and where I could be there while he was doing it.

Another issue with some shops is they are taught to get it within the specs in their computer, unfortunately within specs doesn't necessarily mean aligned. They can have one side at +2% and the other side at -2% and their computer will say it's done, unfortunately that is not aligned, it may be within specs but it will pull and drive like $h!t. Having both sides exactly the same is the key and will make a world of difference.

Having big tires in the rear don't really effect the alignment, having the rear jacked up can effect the caster if there isn't enough adjustment to make up for the rake of the car. They use to make offset upper control are bushings to give you more adjustment but you had to know what adjustments you need before you install them since they get pressed in.
 
See my post on alignment procedure. So many just don't take the time to examine/correct all angles. Then again, how many of you would pay 200-250 for a real alignment anyway?
 
oldkimmer said:
..............Also the K frame wears badly where the lower control bolts thru.......post ur specs, so we can help u out b4 u take it back again and again, u say u want help , so let us help u....lots of times ppl ask questions then dont listen anyways, dont b1 of them......kim........[/QUOT Oldkimmer I trust what u are sayin is true but I don't know the specs the alignment shop used. The K frame is a DC big block A body unit used 1 month when I bought it. The car is Texas vintage with no rust and original spare tire when I bought it. The pitman and idler arms show no looseness that would cause such a dangerous condition. I would've replaced them if so. This car is in the best condition u could immagine. I don't know much about alignment but am learning. This is not my 1st rebuild. It appears when I jack the car up the left side [drivers side] is pushing to the right and too much negative camber while the right side stays pretty straight. Can you tell me what the correct specs should be so I can relate this to Ron, the alignment guy?
I am prettygood with my rides. I think I could have got it as close as the shop. I will take it back but I need some specs from u guys to work with. Thanks again from all of you!
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The best thing to do is get the car up in the air and go over it front to back.That way you can check the torsion bars, lower control arms and k-frame.It is gonna be hard to do on jacks.It could be alingment but most likely it is something else.
 
Caster will make it pull on any road. When you say hit a rise, what kind? how steep? It sounds like you have a bind. Check for wear marks on your linkage and headers. And research "bump steer". Call Bill.
 
Ok forum friends, now I think we are getting somewhere on this problem I am having with Mean Green. I researched "Bump Steer" like Green1 suggested. While I was looking the Duster over yesterday, checking all the components for looseness, I didn't find any looseness. I did notice that when jacking the car under the K member in the center the left front wheel developes a severe toe in which would cause the condition I am experiencing. Bump Steer.
I just changed over to BBP last fall, {73-76} parts on this 71. The lower balljoint arm is configured a little differently than the one I took off. Is it possible this difference has changed the dynamics at the outer tie rod enough to cause the toe-in to cause the Bump-Steer condition. I never had this problem to this extreme until I changed over to BBP. The definition of Bump Steer as described in my research pretty much nails it.
If this is the problem, how do I correct it? Thanks friends, with your help I'll get this solved yet and it'll be safe to drive soon!:read2:
 
Dust1 said:
It really is not likely that the alignment is not correct. I got the very best shop in the area to do it. They are good. They told me to bring it back and they will check it out. I forgot to mention I replaced all steering components too, except pitman and idler arms. All new. Hooker fenderwells. I will jack it up and recheck everything and the torsion bars at the lca's. You are correct michformulaS. It only happens on the rise.
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what did they alighn it to? the 1970 specs in the computer? they are no good. you need a guy that knows what he is doing and not just a guy that puts the lights in the green section.
 
abodyjoe said:
what did they alighn it to? the 1970 specs in the computer? they are no good. you need a guy that knows what he is doing and not just a guy that puts the lights in the green section.
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The only way I can reply to that Joe. Grilliot's Alignment shop. It is their specialty. They have been in business since the Model T. Probably 3rd generation. Ron Grilliot, the current owner is older than I. He aligned it himself. Every hotrodder and musclecar owner in the area take it to Ron.
Ron told me to bring it back. I am just getting some education before I do so I know what questions to ask and be able to talk on his level. Maybe there is something I need to change before I take it back.
I just wonder why he didn't notice the condition when he test drove it??
 
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