Modify stock A arms for caster

[RJ Squirrel]

Well I do love the *** end high with fat tires look, even though doing this robbed me of most of my caster. I have offset bushings installed, but still I can only get one degree. I did the smaller diameter bolts trick on my Polara and it worked, but just seems like a hoaky way to do it.
So now I am considering modifying the A arms by cutting off the rear bushing sockets and welding them back on a little shorter. How much shorter? I was hoping somebody might have done something similar. I would just draw an outline of the arm first, then cut it, lay it on the outline with the ball joint moved back about 3/16 to 1/4 or so?
I know I could just buy the right aftermarket A arms made for this but hey I am a dirt poor cheap *** country boy with a welder.
So any good intel out there?

 

[Kern Dog]

I had a thread about this very thing at FABO a few months back.

The man wants MORE caster. How about this idea?

Some states that have annual vehicle inspections frown upon welded suspension or steering components.
I still think that this modification can be successful. I considered the idea of taking 1/4" out of the rear section and adding 1/4" to the front.
If you have some spare parts and time to kill, you might be able to make it work. The integrity of your welds will determine the durability.
Aftermarket UCAs are $450 and up. This mod would cost next to nothing.
I was able to get 6 degrees of caster with stock UCAs and offset bushings in Jigsaw so I saw no need for surgery. I got these numbers from a 72 Duster with stock UCAs and offset bushings:

Yeah, 3/4 degree negative camber and 5 1/2 degrees positive caster.
There could be a couple of reasons why you have such little caster. I got 4 degrees with stock UCAs and stock bushings so you have something weird going on. Your strut rod bushings could be too thick. Your UCA bushings could be in wrong. You may have the ride height too high.
Just so you know, these cars gain caster as you lower them. The taller they sit, the less caster you will have.
See this chart below. It shows the numbers recorded on an A body front disc knuckle but the other knuckles are not that much different. The chart shows how caster is great at "dive" and terrible at rise. The A body setup has almost 5 degrees positive caster at 2 1/4" below stock and 3.3 degrees negative at 2 1/4" above stock height.

 

[62 Dart Convertible]

I have offset bushings installed, but still I can only get one degree.

Something is seriously awry. Did you install them? Are they installed the right way around? Did you install 1 or 2 offset bushings in each upper arm?

 

[BeepBeepRR]

Look up Junkerup on Youtube. He has some good videos on making your Mopar drive great. Ahh screw it i'll link them.

 

[RJ Squirrel]

Thanks for the tips guys, I believe my aftermarket knuckles for the disc conversion along with the obvious rake, and the fact the car was beat all to hell and had a bent frame rail, LCA, and strut rod is why I have the caster problem. I am going to fab up a jig to hold the bushings in place, calculate how much I have to move the ball joint to get 6 degrees, cut the arms to necessitate hitting the sweet spot, and weld them back up with doubler plates.

 

[RJ Squirrel]

Thanks KD for that thread link, some good info and arguments in there.

 

[RJ Squirrel]

Look up Junkerup on Youtube. He has some good videos on making your Mopar drive great. Ahh screw it i'll link them.

Watching that vid right now- better than Dr Phil
I like that dropping the lower ball joint idea, makes sense.

 

[RJ Squirrel]

Oh boy there is something very wrong here. My degree of caster is actually a degree negative. With A arms adjusted for full positive caster it is still in the negative. Took the driver side arm out, the offset bushings are in right, and the arms appear to be correct. The car had some shoddy 70's used car lot work done after one of its benders, so who knows. I know the K frame is not a 69, the sway bar runs through it, I thought it was from a 70, but maybe it is a newer year or not even a B body? Guess I should find some part numbers.
Well anyhoo I know why it drives like **** no matter how much I try to align it.
EDIT Found the date stamp 1340- May 1970. Should still work.

 

[RJ Squirrel]

Plumb line for reference, the car is on the lift at approx the right rake angle.
The ball joint would need to be moved rearward 1 1/4" to give me 5 degrees positive caster. It is at full droop in this picture, the sway bar links are off and I had the arms at ride height position when I took the measurement.

 

[BeepBeepRR]

Here is the Ebay link to those drop brackets. I think Chris needs to edit his listing.. lol It says 3500.00 But the price is 350.00 for the set including the hardware.

 

[autoxcuda]

Here is the Ebay link to those drop brackets. I think Chris needs to edit his listing.. lol It says 3500.00 But the price is 350.00 for the set including the hardware.

FYI, those are setup to only use on B/E 10-11" drum knuckles.

And maybe 10 large bolt pattern 73-76 A-body since they take the same Lower Ball Joint as the B/E knuckle. Just would need to verify the upper two backing plate bolt size and position.

 

[Kern Dog]

If your steering knuckle/spindle looks like this:

...Then those brackets from Birdsong will not fit.

Here is a tip: The front section of the UCA needs to be adjusted OUT as far as you can go and the rear goes IN as far as you can go to get maximum caster.
You may already know that but it is worth a mention just in case.
A 1970 K member will not pose an alignment problem, in fact you could use even a 1971 or 1972 K member but the mounting pad for the steering box is at a slightly different angle. Otherwise, the suspension points are the same.
I had a 73 Dart that had a negative caster condition on the right side. On closer inspection, the K member was bent quite a bit at the strut rod mount. This pushed the whole LCA rearward at the ball joint end. I could have fixed the K member but I instead just pulled it and used another one.

 

[RJ Squirrel]

I am still stumped trying to figure out how/why it is so far off. LCA's are parallel and square with the torsion bars, and UCA's adjusted all the way back are still over an inch too far forward. Is it even possible I have the wrong UCA's?

 

[RemCharger]

From all I'm reading, the car was in a front-ender and it's crunched. So yes, making a control arm fit the bill would be the custom fix. As far as sectioning an uca, yes that's an old S/S racer trick. They basically make a pie cut and squeeze it together iirc

 

[Kern Dog]

I am still stumped trying to figure out how/why it is so far off. LCA's are parallel and square with the torsion bars, and UCA's adjusted all the way back are still over an inch too far forward. Is it even possible I have the wrong UCA's?

The 1962-72 B body uses the same UCA. The 70-74 E Body uses the same arm. Nothing else fits.
To add:
The QA 1 UCAs I installed added 2 degrees of caster over my stock arms with offset bushings. Total stock UCAs, I was able to get 4 degrees of caster, the offset bushings got me 6, the QA 1s got me to 8.

 

[RemCharger]

The 1962-72 B body uses the same UCA. The 70-74 E Body uses the same arm. Nothing else fits.
To add:
The QA 1 UCAs I installed added 2 degrees of caster over my stock arms with offset bushings. Total stock UCAs, I was able to get 4 degrees of caster, the offset bushings got me 6, the QA 1s got me to 8.

Could an A body arm go in there?

 

[RJ Squirrel]

From all I'm reading, the car was in a front-ender and it's crunched. So yes, making a control arm fit the bill would be the custom fix. As far as sectioning an uca, yes that's an old S/S racer trick. They basically make a pie cut and squeeze it together iirc

Yup that seems to be the answer, the parts are correct, the car itself was just bent too many times in the past. Hell the rear axle housing was even bent, springs too! So custom built UCA's it is. Was just looking at the QA1 arms, but I dont think they would work well in this case.

 

[RemCharger]

Yup that seems to be the answer, the parts are correct, the car itself was just bent too many times in the past. Hell the rear axle housing was even bent, springs too! So custom built UCA's it is. Was just looking at the QA1 arms, but I dont think they would work well in this case.

The other option I was thinking was to put it in the back- cracker ( frame machine)

 

[autoxcuda]

Could an A body arm go in there?

A-body UCA’s are different length and spacing between upper bushings

 

[RJ Squirrel]

So I rigged up a simple fixture, cut it, and moved the ball joint to the new location