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Front End Issues Continue to Haunt Me
#232188
02/22/09 12:13 AM
02/22/09 12:13 AM
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Joined: Apr 2007
Posts: 3,746
Riverside, California
Lil Demon
OP
master
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OP
master
Joined: Apr 2007
Posts: 3,746
Riverside, California
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I am getting so sick of this front end that I cannot stand it. To fix my previous bump steer issues, I spent money and bought new steering arms from LRT, adjustable tie rod ends, factory spindles, and put coil overs on it.
The car aligned great for the first time since I've owned with no issues going forward or backward - woohoo - problem solved and money well spent. Not so fast...........
Today - the car goes straight as an arrow down the track, I cross the stripe and let off and hit the brake - vicious - and I mean vicious front end shake. So bad that I couldn't see - I wanted to pull the parachute handle but was afraid to let go of steering wheel - it was that bad.
I went back to Les Schwab where we aligned it last night. The caster is at +8 (as much as it can get), the camber is at -1.8, and it was neutral on the toe.
Guys with fast(I know that is relative) back half-4 link cars - what are your front settings? Others - any recommendations?
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Re: Front End Issues Continue to Haunt Me
[Re: Lil Demon]
#232189
02/22/09 12:23 AM
02/22/09 12:23 AM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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I run about 10* caster, 0 camber and 0 toe in. It sounds like you have something flexing.... were your wheel bearings tight/snug EDIT Also Bill was the front alignment done with the body up 1"... check your toe in at 1" up... it could be going toe out and thats not good 
Last edited by MR_P_BODY; 02/22/09 12:27 AM.
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Re: Front End Issues Continue to Haunt Me
[Re: dthemi]
#232192
02/22/09 12:36 AM
02/22/09 12:36 AM
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Joined: Jan 2003
Posts: 19,382
Las Vegas
Al_Alguire
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 19,382
Las Vegas
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I agree..For me 1/16"+- has always worked well in a back half car. You might also just give the front a once over, always a good idea. Never checked that driver side bearing at the track.
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
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Re: Front End Issues Continue to Haunt Me
[Re: Chuck@Best_Machine]
#232198
02/22/09 12:59 AM
02/22/09 12:59 AM
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Joined: Feb 2006
Posts: 698
Alberta Canada
Edge
mopar
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mopar
Joined: Feb 2006
Posts: 698
Alberta Canada
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Had the same problem with the LRT front end on the duster. Also found some cracks in the lower arm. Repaired arm and it is now acceptable.
76 Duster
work in progress
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Re: Front End Issues Continue to Haunt Me
[Re: Edge]
#232199
02/22/09 01:12 AM
02/22/09 01:12 AM
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Joined: Apr 2007
Posts: 3,746
Riverside, California
Lil Demon
OP
master
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OP
master
Joined: Apr 2007
Posts: 3,746
Riverside, California
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My front end is very bastardized. Stock front clip, DARE K-Frame (on it when I bought it - I didn't know), Magnum Force tubular uppers (non-adjustable), Stock LCAs, LRT steering arms, Flaming River Pinto R/P, Aldan coil overs. Looking at the vids - the wheels are definitely toeing out when it lifts them in the air. So - if I set the toe at ride height +1" - do I set it at 1/16" in? The negative caster I think may be the best it can get - not sure. I may need adjustable UCAs 
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Re: Front End Issues Continue to Haunt Me
[Re: Lil Demon]
#232201
02/22/09 01:22 AM
02/22/09 01:22 AM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
My front end is very bastardized. Stock front clip, DARE K-Frame (on it when I bought it - I didn't know), Magnum Force tubular uppers (non-adjustable), Stock LCAs, LRT steering arms, Flaming River Pinto R/P, Aldan coil overs.
Looking at the vids - the wheels are definitely toeing out when it lifts them in the air.
So - if I set the toe at ride height +1" - do I set it at 1/16" in?
The negative caster I think may be the best it can get - not sure. I may need adjustable UCAs
Yes set the toe at 1/16 in at 1" up on the body. I
assume you just made a error in saying caster instead
of camber but you would be better off with adjustable
UCA's
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Re: Front End Issues Continue to Haunt Me
[Re: Lil Demon]
#232206
02/22/09 02:24 AM
02/22/09 02:24 AM
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Joined: Jul 2008
Posts: 610
Boise
Moparteacher
mopar
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mopar
Joined: Jul 2008
Posts: 610
Boise
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The length of the inner-to-outer tie rod must be equal to the length of the lower control arm (pivot to pivot). They must also rise and drop in a parallel plain. Anything different and you get a change in toe as the suspension goes through jounce and rebound, in other words "bump steer".
The outer tie rod can be shimmed toward or away from the knuckle to obtain the parallel travel, but a rack-n-pinion (inner/outer tie rod) that doesn't match the length of the lower control arms gets a little more complicated.
You can heat and bend the lower ball joint arm up and down or inward or outward to help achieve the equal length and parallel, but only so far.
The Mopar chassis book shows you how to graph changes in toe throughout jounce and rebound and how to correct it. It works for any LSA suspension, but with miss-matched parts there may be only one solution and that's to purchase parts that are engineered to work together.
When it's all said and done camber should be at or near zero regardless. Cross-camber and cross-caster should be less than .5 degree. Preferably zero for a flat track. Excessive positive caster will cause rapid wheel shimmy. You need only enough positive caster to maintain directional stability.
One last thing. Excessive positive scrub radius will put an excessive load on the suspension components and could be a cause for flexing and cracking.
Positive scrub radius occurs when the alignment of the upper and lower ball joints meets the road inside of the point at which the center of the tire meets the road.
Positive scrub radius results from using smaller diameter wheels and tires and/or using a wheel that has little or no offset (common with front runners).
Some positive scrub radius is OK; it's the excessive that causes problems.
Good luck
Last edited by Moparteacher; 02/22/09 02:28 AM.
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Re: Front End Issues Continue to Haunt Me
[Re: Moparteacher]
#232207
02/22/09 02:31 AM
02/22/09 02:31 AM
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Joined: Apr 2007
Posts: 3,746
Riverside, California
Lil Demon
OP
master
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OP
master
Joined: Apr 2007
Posts: 3,746
Riverside, California
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Quote:
The length of the inner-to-outer tie rod must be equal to the length of the lower control arm (pivot to pivot). They must also rise and drop in a parallel plain. Anything different and you get a change in toe as the suspension goes through jounce and rebound, in other words "bump steer".
The outer tie rod can be shimmed toward or away from the knuckle to obtain the parallel travel, but a rack-n-pinion (inner/outer tie rod) that doesn't match the length of the lower control arms gets a little more complicated.
You can heat and bend the lower ball joint arm up and down or inward or outward to help achieve the equal length and parallel, but only so far.
The Mopar chassis book shows you how to graph changes in toe throughout jounce and rebound and how to correct it. It works for any LSA suspension, but with miss-matched parts there may be only one solution and that's to purchase parts that are engineered to work together.
When it's all said and done camber should be at or near zero regardless. Cross-camber and cross-caster should be less than .5 degree. Preferably zero for a flat track. Excessive positive caster will cause rapid wheel shimmy. You need only enough positive caster to maintain directional stability.
One last thing. Excessive positive scrub radius will put an excessive load on the suspension components and could be a cause for flexing and cracking.
Positive scrub radius occurs when the alignment of the upper and lower ball joints meets the road inside of the point at which the center of the tire meets the road.
Positive scrub radius results from using smaller diameter wheels and tires and/or using a wheel that has little or no offset (common with front runners).
Some positive scrub radius is OK; it's the excessive that causes problems.
Good luck
You know your stuff - now - how close to Rocklin, CA are you?
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