caster mod in a CPP lower control arm

[dmboshkov]

Hello, could you please tell me if anyone has done the caster modification in a CPP lower control arms, I need caster, and I thought that these control arms would add it but nothing, zero nada.
Now I am thinkig to add the mod holes 1/2" behind the current ones, if anyone has done this in a CPP LCA, please let me know how much caster this mod adds or any information would be greatly appreciated.
Thank you.

 

[Ricko1966]

Hello, could you please tell me if anyone has done the caster modification in a CPP lower control arms, I need caster, and I thought that these control arms would add it but nothing, zero nada.
Now I am thinkig to add the mod holes 1/2" behind the current ones, if anyone has done this in a CPP LCA, please let me know how much caster this mod adds or any information would be greatly appreciated.
Thank you.

If you are just needing caster why can't you just add or subtract shim from the upper?

 

[ali_c20]

If you are just needing caster why can't you just add or subtract shim from the upper?

As it was done from the factory. Lower control arm is fixed, upper control arm is adjusted with shims.

https://www.gmsquarebody.com/threads/camber-adjustments.19597/post-362202

Welcome to the forum post some pics so that we can see what's going on.

 

[Radiohead]

If you are just needing caster why can't you just add or subtract shim from the upper?

My guess is that the aftermarket lower control arm geometry is incompatible with what the stock upper control arm can compensate for. If I'm reading the first post right. If thats the case, maybe it requires a CPP upper control arm kit to get the alignment specs back?

Is there a printout from an alignment machine to look at?

 

[Ricko1966]

My guess is that the aftermarket lower control arm geometry is incompatible with what the stock upper control arm can compensate for. If I'm reading the first post right. If thats the case, maybe it requires a CPP upper control arm kit to get the alignment specs back?

Is there a printout from an alignment machine to look at?

If that's the case use problem solver offset shafts to get a bigger range of adjustment. Anyways that would be my 1st approach.

 

[xm20k]

If that's the case use problem solved offset shafts to get a bigger range of adjustment. Anyways that would be my 1st approach.

The CPP control arms won't take a stock type cross shaft.

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[bluex]

Some like to do this mod to reduce the overall shim stack by starting out with more caster than stock. I've never had it happen but have heard of people having issues with the shims popping out an this could help reduce the number needed overall an combat that issue.

 

[Ricko1966]

Some like to do this mod to reduce the overall shim stack by starting out with more caster than stock. I've never had it happen but have heard of people having issues with the shims popping out an this could help reduce the number needed overall an combat that issue.

O.P. if this was/is an issue. Personally I'd measure my shim stack and make a solid bushing,or use washers. Yes a little more PITA but it would solve the problem. Or even make a semi fit bushing,a little undersizedbut set final setting with 1 final shim

 

[idahovette]

Never in my years of Alignment did I have a problem with shims "popping" out. Of course I tightened the sh!t out of the upper control arm attaching nuts. I had a special 3/14 box end(1/2 ton) and a 7/8 box end(3/4 ton), both bent in a couple of places to facilitate the job? I used to be stronger, too

 

[Radiohead]

Alignment was the operation I enjoyed most. So much so, I spent way too much time in tire shops as an alignment tech. But, that was way back in the 20th century.

 

[xm20k]

I'm still curious as to what this mod is he's on about never hear of it and can't find it based on the info he posted.

Also wasn't the alignment/suspension guy but if you needed an engine, trans or rearend swapped or rebuilt, I got you.

 

[Rustisbest]

My caster mod (with pictures) - The 1947 - Present Chevrolet & GMC Truck Message Board Network

My caster mod (with pictures) Suspension

67-72chevytrucks.com

I didn't know you could adjust CASTER on these with shims. I thought that was camber only?

 

[xm20k]

My caster mod (with pictures) - The 1947 - Present Chevrolet & GMC Truck Message Board Network

My caster mod (with pictures) Suspension

67-72chevytrucks.com

I didn't know you could adjust CASTER on these with shims. I thought that was camber only?

Interesting, they are modding the mounting of the lower control arm in the frame to gain more caster than you could with shimming, however the CPP arms (I know I run them) do not use a stock type bushing set so the offset shafts are out, unless you drill a second set of dimples so they sit farther forward in the frame, which appears to be maybe what the OP is talking about. I have no idea if this a good idea on these.

 

[idahovette]

Ya gotta move the lower arms forward to get more positive Caster. All of the adjustment on the original C 10s, C20s, and C30s was shims on the upper control arms.....more shims on the front equals more Camber, more Caster, more on the rear equals less Caster, more camber and so on. After you have done a few, you get to know how many and what thickness shim you need to get what you want. Probably a hundred or so...lol.....became 2nd nature to me in a farming community with a LOT of Chevy/GMC pickups.

 

[Fat 454]

Ya gotta move the lower arms forward to get more positive Caster. All of the adjustment on the original C 10s, C20s, and C30s was shims on the upper control arms.....more shims on the front equals more Camber, more Caster, more on the rear equals less Caster, more camber and so on. After you have done a few, you get to know how many and what thickness shim you need to get what you want. Probably a hundred or so...lol.....became 2nd nature to me in a farming community with a LOT of Chevy/GMC pickups.

Any chance of you posting a seperate thread on this to explain with some examples? I'm sure it would help a lot of people, and just like carb adjustments, modern shops don't seem to understand shim pack adjustment anymore.