My caster mod (with pictures)

[ranger2339]

Originally Posted by jjzepplin

Just trying to save a life here. Sorry I was dramatic. I meant no harm. Just doesn't look safe. If you moved the arm forward by the mod method, and then moved the ball joint mounting then didn't you basically just move the place where the spring sits? I just don't follow what you've done here. I am a little slow today. Again, I mean no harm just trying to figure this out. As I understand the MOD it moves the whole arm and that is what it is intended to do. Or did you move the ball joint in the same direction creating even more caster?

Yea no worries, I didn't mod the cross shaft, just the ball joint mounting location so the spring pocket stays the same.

Originally Posted by tinydb84

I did my first set of arms in a similar way.

The plating is more important on the sides than top and bottom. You lost the strength of the arms when you cut through the sides. Think of bending a ruler when it is flat vs standing on its side.

I totally missed that you shortened the arm a bit in order to keep it alignment with one of the sides there, ah damn. Any pics of the final outcome of your arms?

Might just do the cross shaft mod on another set of arms if I messed these up too much.


I do appreciate all the feedback, as Im not the best at this.

[tinydb84]

I dont have any pics of them done. You could easily weld a piece of steel to connect the sides.

Here is a pic of how I did a second set

[crakarjax]

Originally Posted by tinydb84

I dont have any pics of them done. You could easily weld a piece of steel to connect the sides.

Here is a pic of how I did a second set

You've got that album set to private

[ranger2339]

I will probably do my next set like that, just tight on funds and wanted to take a stab at it with the resources I had. Will be a long winter so I have time.

Still would have to figure out the other side with some bracing.

[crakarjax]

It'll be really hard to get your camber right unless you also take in the upper arm, and then you'll need to think about wheel backspacing (which you'd already have to do anyway most likely.

[ranger2339]

Yea I did not shorten the arm much so camber should be ok. Just made some relief cuts and bent the arms u bend side supports in and welded them up. In the end should work, seems strong, but will probably be doing the BJ cup replacement mod as it seems the strongest and leaves the spring pocket and integrity of the arm in place?!

Sorry to hijack the thread, I just value the opinions here. I'm done now.

[tinydb84]

I don't have my album set to private. Im not logged in and can see the pics. Maybe photobucket was down for a bit.

Anyway. The relief cut should work. I put ball joint cuts in my first set of arms and welded a tab to the airbag cup. Probably overkill.

I shortened the lowers 7/8'' and the uppers 1/2''. Camber was fine with one shim. I know it would reduce camber gain but I was more concerned with fender clearance.

[69gmcc10]

ranger2339,

No apologies needed this is not high-jacking. You brought a new idea to the table and with some adjustments to your idea we all learned something and that is what we are here for.

I like your modifications especially with the recent adjustments. I would plate both the inside and outside of both the leading side and trailing side with some rosette welds and a good perimeter weld all around. also run a "skid plate across the bottom that strattles the welded joint to prevent any outward deflection of the sides.

Let us know how it ends up!

[HO455]

I thought I would add some additional information to this thread. I went this route on my Burban by obtaining an extra set of used control arms and rebuilding them. By the time I was done I had four used control arm shafts off of three trucks. The measurements I show in the photos below. All of the used ones were 3" plus or minus a 1/16". The two new Moogs (K6147) I used were at 2 15/16". The measurements are from the end of the shaft to the center of the index hole. I did this to avoid the differences in the machined areas for the seals between old and new shafts as previously discussed. (Second photo) After much measuring and double checking I milled a 3/4" index hole (and finished it off with an 5/8 drill bit just in case the rivet was taller than I expected) at 3 3/4" from the end of the shaft.
I haven't got the truck on the alignment rack yet. (Still waiting for a tie rod end). But I will post the spec's when I get them. A couple of things I noticed when doing this. One is as the lower control arm moves forward it changes how the brake hoses flex and I had to tweek the brackets on the cross member to keep the hoses from rubbing when the wheels are hard over. In addition I had to move my sway bar frame mounts forward 3/4" to keep the ends of the factory sway bar from rubbing on the airbags.
The factory index holes measured 11/16" and the Moogs were 23/32". The index rivets were 19/32" in diameter. That means with the replacement shafts there is 1/8" of slop forward and back. As both of my shafts had been knocked back and had damaged the rivets, I had to drill them out and replace them with 1/2" socket head cap screws as the OP did. The old rivet holes had to be drilled out to half inch. As I didn't machine the index holes deep enough I had to grind a 1/16" off the top of the cap screws to keep them from holding the shaft away from the saddles.

[HO455]

Also when doing this modification on a bagged truck you will have an additional shock issue. The shock will contact the brake line bracket or the cross member at full drop. To solve the problem I removed the stock shock mounts and made new ones that hold the shock away from the control arm farther and about an inch closer to the frame. I apologize for the poor photos.

[crakarjax]

Thanks for the heads up on that, nice to know what I'll be running into

[HO455]

You're welcome. I posted some more photos of the shock mount project and a little more information on "The WMB" thread on page 11 (I think its page 11)

[HO455]

Got a short window on the alignment rack this afternoon so I got a set of initial readings. This is with the shim sets that the PO had installed and I just reused as a base line. My first impression was "Yikes I went too far!". I may have to pull the lower arms and mill a third location if I can't remove some of the caster!!!

[HO455]

After going through it all this is what I came up with. The Burban is bagged so to get the camber where it is I did go with a one inch higher ride height. The biggest driver of this was to reduce the number of shims so now I have full thread contact on the upper control arm bolts. I will drive it this way for a while and see what I decide what to change next.

[Slowguy]

Originally Posted by crakarjax

I got my bag mocked up, but it looks like it'll have stress in bad places. Then again, I've never run bags. Anyone know if the offset pictured will cause more than a marginal decrease in bag life? I also have no idea what the internal bumpstops on these bags look like. I'm a little worried that they aren't making solid contact as pictured.

I didn’t even know about this mod until reading a build thread on “green Gus” since I have everything apart for my nut and bolt build I figured I had better do this now or I may regret it.

Anyway, you were one of the only ones to mention bags. I too am using air and wondered how well you solved the issue of the crooked bag? Did you just relocate the mount holes in the top bag bracket? I actually cut out the lower indent section of my lca and welded in pockets to the entire bag will now sit in the pocket when completely deflated. This also allows me to run with more air in the bags at a lowered ride height. I’m wondering if this is going to affect or alter my attempt at this modification?

[HO455]

Here is a link to my Burban thread page on my front bag installation. I did have to reposition the bag on the upper plate to get the bag to sit straighter.
You didn't mention what make and model of bags your installing. If your using the SS7 bags I used, your plan with the control arms should work well. I haven't done it yet but I am planning to cut my lower cups down to get a higher pressure at ride height.

http://67-72chevytrucks.com/vboard/s...698377&page=10

[Slowguy]

All I have are the cheap 2600# airbags that came with the truck. I assume they are mostly the same? If not, it's not a big deal for me to change to a different brand right now.

[HO455]

Those bags are what I replaced. They gave me the same ride height but required higher air pressure to do it on my Burban. I can't really give you a good ride comparison between the two as the entire suspension was worn out with the old bags and the new bags are part of the total suspension rebuild. They are also smaller in diameter so you will have more room for misalignments in the top and bottom mounts as the suspension moves.

[crakarjax]

Originally Posted by Slowguy

I didn’t even know about this mod until reading a build thread on “green Gus” since I have everything apart for my nut and bolt build I figured I had better do this now or I may regret it.

Anyway, you were one of the only ones to mention bags. I too am using air and wondered how well you solved the issue of the crooked bag?

Did you purchase those cups somewhere? I think I'm going to want to cup my LCAs also.

Anyway for posterity here, it's best to keep the bag centered on the LCA to evenly distribute load to the LCA bushings.

[Slowguy]

Originally Posted by crakarjax

Did you purchase those cups somewhere? I think I'm going to want to cup my LCAs also.

Anyway for posterity here, it's best to keep the bag centered on the LCA to evenly distribute load to the LCA bushings.

Yeah. It took me a bit to find these just because of the name needed to search for. I kept looking for “cups” and even if you search their website you can’t find them with that search term. It wasn’t until I used “pocket” that I actually found what is was looking for.

I bought them here : http://www.bcfab.com/Front-Drop-Pock...10_p_1263.html

I could have fabbed something myself but I figured for the amount of time saved searching for the correct sized steel, cutting and welding, etc...I’d be better off just spending the money on these. They went in pretty easy and I think I’ll be glad I did it once everything is all back together. It will allow the front to drop quite a bit more.

[HO455]

For what it is worth from what I have done on mine I would recommend going with a smaller diameter bag like the 2600 as opposed to the Slam SS7 that I used. It will be easier to set up the bag at ride height so it won't touch the pocket.

[Slowguy]

I think I’m about done with the front end. I think it’s working out pretty good but we’ll see when it’s actually back together and has some weight on it. Have to do some research to see how the caps are supposed to be (properly) threaded onto the upper a arm bars. I can see now, how those bars are used for alignment purposes depending upon if the rear or the front caps are threaded more or less.

I think the bags are set as straight as I can get them. The caster mod really seemed to have set the lower ball joint pretty far forward but I guess that’s a good thing (especially since I’ll be using an ls ps pump - plenty of hydraulic assist). Also it’s nice to be able to get all the air line fittings tight, properly assembled, and routed the way I want. The last guy did a real hack job with multiple things.

[HO455]

Nice work. I like the bump stops. What are they off of?

[Slowguy]

I can look it up if you want. Thy were cheap. I just ordered them online somewhere. Don’t know yet, they are fairly soft rubber but pretty tall. I may end up cutting it down a rib or two. We’ll see how it sits when back together.

[HO455]

[QUOTE=HO455;7998948 In addition I had to move my sway bar frame mounts forward 3/4" to keep the ends of the factory sway bar from rubbing on the airbags.
.[/QUOTE]

Just a note on this quote. If you need to reposition the sway mounts for clearance try to keep the bar as close as possible to the control arm. The theory is the shorter the distance between the mount on the arm and the front of the bar the stiffer the bar will be. As little as 1/2 " either way will be noticeable.
In the photo the shiny spots near the ends of the bar shows the location of the end mounts as the factory installed them. If the bar is repositioned in the direction of the arrow the mounts can now ride where the blue line is. Basically instead of 1/2" of bar sticking past the mount there will be one inch sticking past.

Cheap sway bar upgrade!