My caster mod (with pictures)

[Walkersan]

I performed this mod tonight on my 72 C10. I was able to move the lower arm forward 1 inch with minimal trimming on the lower arm and cross member, as to not remove too much material from either.

My question now is, it appears the shock is going to contact the cross member. Even if it clears, this mod moves the lower shock mount forward with the lower arm and increases the angle of the shock more than stock, which is not a good thing. What have any of you done to correct this?

Side note, I already have the heavy duty upper front shock re-locators from CPP since my upper front shock mounts have already been ripped out and poorly welded by the previous owner. My plan was to mount them in a position to eliminate some of the angle inherent in the front shocks, but I fear with this mod I will limit my options there. I may end up fabbing some customer lower mounts that give me more room to work off of the lower arm... more work... sigh. the things I do for fun.

Thanks

Walker

[chevyrestoguy]

Walker-
If you can, try to get a front shock angle measurement from a stock truck, or do some math and figure out what yours was in the original configuration. I think that if you take your CPP bracket and slide it forward the same amount you moved the lower arm, you should be just fine. You could extend the lower mount out a little, but I would prefer keeping the lower eyelet of the shock as close to control arm as possible, like the factory did. In your case, I would just mock up the CPP bracket and slide it to where you like it, and drill it up.

[Snailed]

What are the compromises of forcing the spring to be 1" out of alignment when you move the lower arm forward?

[chevyrestoguy]

I'm only .75" forward, and I figured that it wouldn't be an issue. The coil spring is approx. 11" tall when under compression, and as long as the pigtails of the spring are locked in the stops, I think it'll be fine.

That is a very good question, though. My truck isn't on the road yet, so I can't give you any "dynamic" feedback.

[mac808]

Wow! Awesome write up on a ingenious DIY mod! A nice alternative to inch forward arms to alleviate the same issue.

[hgs_notes]

I've been working on this mod over the past couple weeks as part of a front end rebuild. I moved the LCA's fwd 5/8" ans still had to do some grinding on the U-bolt saddles and on the inside radius of the LCA near rhe saddle for full up travel. No big deal. But I am having issues with the shocks. I still have the stock shock mounts on my 71 and the angle on the bottom is too much to get the bolt in.

Have you installed shocks on yours yet? Are they the same mounting style as the 67-72? I have been considering getting the CPP mounts or the kind ORD sells for extending the upper mounting on 4x4's, or just making my own upper mount. The simplest fix would be to just open the hole up a bit to get the bolt to slide in. I like the idea of the higher mount point in any case since my truck is lowered with shorter coils about 3.5".

Here's where I'm at now...

[RexDodge]

I did this mod last year. My truck drives absolutely awesome around town or on the freeway. We got similar results (+7* caster). I've done some "testing " and have not noticed/had any bump steer issues. I do remember having to clearance some spots to have full travel. I have notes in my build thread. Good luck all, great mod!

[chevyrestoguy]

I haven't installed my shocks yet, but it looks like they should work. I even bought the upper shock mounts from CPP, but I couldn't use them because I did all of the work on my inner fenders and they wouldn't clear. I Z'd my chassis 2" and did a bunch of work on the inner fenders to make it all look factory. On a stock chassis with stock inner fenders, the mounts would have worked just fine. Once I get all of my rear suspension work completed, I'll install the front shocks and see if everything is going to be OK.

[chevyrestoguy]

Originally Posted by RexDodge

I did this mod last year. My truck drives absolutely awesome around town or on the freeway. We got similar results (+7* caster). I've done some "testing " and have not noticed/had any bump steer issues. I do remember having to clearance some spots to have full travel. I have notes in my build thread. Good luck all, great mod!

That's great news and I'm really stoked that you got the results you were hoping for. Seven degrees of caster is outstanding, and that will make a huge difference on the freeway. I'll bet you can drive your truck with 1 finger at 70mph. Vehicles with limited caster will wear you out because you're constantly "chasing" the steering to keep it tracking straight. Have you ever drove an old Ford truck with the Twin I Beam suspension? It's awful.

[RexDodge]

Originally Posted by chevyrestoguy

That's great news and I'm really stoked that you got the results you were hoping for. Seven degrees of caster is outstanding, and that will make a huge difference on the freeway. I'll bet you can drive your truck with 1 finger at 70mph. Vehicles with limited caster will wear you out because you're constantly "chasing" the steering to keep it tracking straight. Have you ever drove an old Ford truck with the Twin I Beam suspension? It's awful.

Worn out king pins = chasing it between the white lines!

[hgs_notes]

Heres my new upper shock mount.


Mounts up like this...

[69gmcc10]

nice fix!

[solidaxel]

I just changed engine and trans (LQ4/4L60E) on my 78 and drove it around the block. everything works great but the steering feels like super power steering, very light feeling.
The pump on the new engine is a 2003 5.3 so is there any difference in pressure to make the steering feel so "light".
I need to replace the bushings on the LCA so this thread is right on time!
When complete with this mod and gaining more castor is that going to change the feeling of the light steering?
The truck already has 2" spindles and springs have a coil cut, but I don't remember it feeling this "light"
I did not read any more about this mod changing the Ackerman or the steering links, is that going to be a concern by moving the shaft .75"?

Thanks for all the great wright ups and pics.

[ChrisDollins]

Thanks for the awesome write up! Like everyone I can't leave well enough alone and have been thinking about doing this. But has anyone done this with the nonrubber bushing a arms? I just changed the ball joints and spindle to a '79 suburban for disc. Is there an advantage with the new arms with bushings?

Chris

[chevyrestoguy]

Originally Posted by ChrisDollins

Thanks for the awesome write up! Like everyone I can't leave well enough alone and have been thinking about doing this. But has anyone done this with the nonrubber bushing a arms? I just changed the ball joints and spindle to a '79 suburban for disc. Is there an advantage with the new arms with bushings?

Chris

Chris-
Not sure what you mean by non-rubber, but I'm thinking you're meaning polyurethane? I used Energy Suspension bushings on my lower control arms, and it went together just fine. I've had good success with their products in the past, so I used them again.

I used all 1979 suspension components for my truck as well. I got a 1/2 ton Suburban and swapped out the entire front suspension and the 12-bolt rear end.

[SCOTI]

Originally Posted by chevyrestoguy

Chris-
Not sure what you mean by non-rubber, but I'm thinking you're meaning polyurethane? I used Energy Suspension bushings on my lower control arms, and it went together just fine. I've had good success with their products in the past, so I used them again.

I used all 1979 suspension components for my truck as well. I got a 1/2 ton Suburban and swapped out the entire front suspension and the 12-bolt rear end.

Did he (ChrisDollins) mean poly bushings or the pre-73 rubber lined steel sleeves that HD trucks got through 91? Either choice would have less deflection vs 73-87 C10 rubber bushings. Both will transmit more road vibration too.

Which is better depends on what you seek (performance or cushy ride quality).

[chevyrestoguy]

Originally Posted by solidaxel

I just changed engine and trans (LQ4/4L60E) on my 78 and drove it around the block. everything works great but the steering feels like super power steering, very light feeling.
The pump on the new engine is a 2003 5.3 so is there any difference in pressure to make the steering feel so "light".
I need to replace the bushings on the LCA so this thread is right on time!
When complete with this mod and gaining more castor is that going to change the feeling of the light steering?
The truck already has 2" spindles and springs have a coil cut, but I don't remember it feeling this "light"
I did not read any more about this mod changing the Ackerman or the steering links, is that going to be a concern by moving the shaft .75"?

Thanks for all the great wright ups and pics.

The caster mod may tighten up the steering feel ever so slightly, but I think the culprit for your light steering could be your pump, which was designed for a different type of power steering (rack and pinion). You might want to call one of the steering places like Flaming River or Borgeson and run your symptoms by them and see what they say. They might recommend installing a restrictor in line with the pressure hose to slow the fluid down.

Not sure about the Ackerman change, but the movement of the LCA .75" forward is not going to move the tie rod attach point on the spindle hardly at all. If anything, it'll roll the attach point to a very slightly rearward angle, but will be compensated by the tie rod adjustment and have no affect.

[chevyrestoguy]

Originally Posted by SCOTI

Did he (ChrisDollins) mean poly bushings or the pre-73 rubber lined steel sleeves that HD trucks got through 91? Either choice would have less deflection vs 73-87 C10 rubber bushings. Both will transmit more road vibration too.

Which is better depends on what you seek (performance or cushy ride quality).

Good catch. I forgot that he had a '66 and just did a spindle and brake swap and probably kept the original '66 control arms. Makes sense now!

[ChrisDollins]

Sorry guys yea. Still original '66 a arms. I kinda thought they might have a little less deflection, but didn't know if I was missing something. I've always been a fan of a stiff suspension unless its a drag car. Would like to go a more pt route with this truck.

Chris

[Paul Y]

Gentlemen,

Thank you for a very informative post.

I wonder if you could clarify one point for me. Would this same modification work on 66 LCA's? Or is something else required?

Many thanks.

P.

[bdiamond]

Originally Posted by INSIDIOUS '86

INSIDIOUS: Did those balljoints come with those boots?

[SCOTI]

Originally Posted by INSIDIOUS '86

I have pics of mine located 3 forward

Curious.....

Everyone has commented about the need to measure as it seems some can't even move the LCA's .75" forward w/o interference. How did you move yours 3"?

[jjzepplin]

May be a typo. 3/4" may be what he meant. 3" would be way too much.

[SCOTI]

Originally Posted by jjzepplin

May be a typo. 3/4" may be what he meant. 3" would be way too much.

That's my guess as well....

[picklito]

Originally Posted by Custom 68

This looks good, I was only able to move mine forward 3/8 inch without modifying my perches or the mount. Until I started I didn't know that there was additional mods needed to move the thing forward. I was not ready to cut into my cross member since I was ready to get back on the road so I only moved it a little. I figured anything would help.

Custom 68,
Did you ever get alignment specs? I'd like to know how much caster increase you got with the 3/8" movement. Thanks!