Strut rods and caster

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gliderider06

gliderider06

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Hi guys have a few questions... 71 Charger that I have replaced everything on the suspension/drivetrain. Converted it to power disk brakes, 6 leaf rear springs, hemi torsion bars, all moog steering components. I had taken it to be aligned today and my alignment guy could not get me any positive caster on it. The best he could get was -1.6*(L) and -1.3(R). When I rebuilt the front end I used the improved design moog strut rod bushings, which he thinks it could be pushing the LCA back and not allowing me to get any + caster. Also he said with the car sitting high in the back due to the leaf springs is also adding to the -caster. I ordered new front spring hangers to lower it 1.5" and removed 1 leaf to help lower the car in the rear.
Now, I am thinking of buying some adjustable strut rods to help me pull in some + caster. Any thoughts on this? I was looking at the ones from reilly motorsports, or the ones from Mancini.
Thanks!
 
The April 2012 issue of Mopar Action has a very good article by Richard Ehrenberg, SAE. It is entitled "UPCHUCK! Steering chuck and alignment angles upgrades for precise control." It should be on news stands now, but might not yet be on their website.
 
Did your front end guy first set correct front ride height? If this procedure is not done first, you will never get a proper adjustment.

I have had problems with front end technicians failing to follow the three simple steps to align a Chrysler torsion bar suspension outlined in the FSM. They don’t understand how the geometry works, and the importance ride height contributes to the outcome.

Crawl under the car, measure and calculate the existing ride height, and compare to factory spec. If it is correct, than Moog correcting bushings can be installed.

Due to some frame rail sag, and upper control arm deformation, Moog offset bushings can help to gain back 2 or so degrees of positive caster. You will need to purchase two sets of two bushings to re-bush both front and rear bushings of each UCA.
 
Yes, the ride height was set when I brought it to him. The springs I have on the rear had the car jacked up pretty high, so I removed 1 leaf, and put a set of the 2 position front spring hangers on it and it lowered the car 2" in the rear. I used all Moog components on it, but not the off set bushings for the upper control arms. I did talk to another front end guy today and he told me that the Moog "improved design" strut rod bushings will cause the LCA's to be pushed back and will give me the -caster. He told me the first thing I should do is put in the stock rubber bushings that Moog makes and that most likely will fix the caster issue. He said that he hs always had issues with alignment when those bushings are used on Mopars.
 
You don't want the strut rods to be pulling or pushing excessivly against the LCA's and force more or less caster. The LCA-bushings will wear out pretty fast this way.
The LCAs should be at 90° to the centerline of the car all the time.
Camber & Caster is set with the UCAs. Nothing else.
 
Gliderider06:
Yes, the ride height was set when I brought it to him
Click to expand...

Check your ride height again. I have got the car back after an alignment, and found one side 1.5 inches higher than the other. Some of these guys don’t have a clue. You have to check their work.

Hopefully, your guy followed directions, and did not try to reinvent the wheel…

Moog problem solver upper control arm bushings will fix your caster problem, and most likely enable a +2 degree final setting or close to it.
 
I changed the strut rod bushings today for the standard Moog's. Just changing them from the "improved design" bushings, pulled my lower control arms forward a little over 1/2 inch. The other bushings were pushing the LCA's back and I could see it in the LCA bushings. It rides a whole lot better and It has not been aligned yet. Something you should look for if using the improved design bushings.
 
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