My caster mod (with pictures)

[BMERDOC]

Originally Posted by picklito

Not sure I'm following this. 1/8" (where?) equals .5"(where?).

Uppers back is a good idea, too. Before I found these threads I was only thinking of lowers forward cuz I also wanted to move the wheel forward in the well, mainly for cosmetics. Obviously, uppers back would negate a little of this, but I'd take 6 degrees over a perfectly centered wheel!

I probably shouldn't include myself in the conversations while I'm half asleep on the couch. Now I need to go back and re-read everything I wrote.

I have been thinking about elongating the upper cross shaft locating holes for finer adjustments, leaving the shims only for camber adjustments (1/8" of motion would equal .5 degrees of movement). I need to go back and look over your math and Scoti's alignment numbers.

[69gmcc10]

I have become quite fond of this thread as of late, probably because I am at this point in my build and I wanted to say thank you all for being a part of this growth and development to improve our vehicles.

I know there is some discrepancy in the OE and aftermarket lower shaft index holes and I Just wanted to share what I removed from my truck last night. As far as I can tell from the amount of play on the ball joints and the shaft bearings coupled with speaking to the brother and mechanic of the long term owner of the truck my lower shafts on my 72 are original. The hole is indexed 1 1/2" back from where the shaft decreases in diameter to accept the arm (photo may be deceiving). I will post numbers on what my moog replacement shafts come indexed to and then have them re-indexed with 2 or 3 longer indexed hole locations for adjustment at a machine shop.

[picklito]

Originally Posted by 69gmcc10

I have become quite fond of this thread as of late, probably because I am at this point in my build and I wanted to say thank you all for being a part of this growth and development to improve our vehicles.

You, too! Thanks! Good pic.

[jnickell41]

The pictures below are of my recently delivered CPP lower shafts. As you can see the indexing holes are already at 2" from where the shaft drops in diameter.

These will be going on an '87 2wd, should I bother getting holes drilled at 2.25"?

[Domer]

What is the distance from hole to hole center? The factory ones are around 8.xx inches. Where as the pins are 9"

[jnickell41]

I'll check when I get home. Does this influence anything, I thought only one end indexed in the the frame member?

[BMERDOC]

Only one does from the factory. What box did those shafts come in?

[Johnny_Lamebridge]

Originally Posted by jnickell41

As you can see the indexing holes are already at 2" from where the shaft drops in diameter.

Just my opinion... but I don't think you can compare the steel bushing and rubber bushing type shafts with one another. Who's to say that the shoulder you're measuring from is the same on both types of shafts?

I think all of these measurements would be best taken from the centre of the LCA shaft. That way, we could accurately compare any type of LCA shaft. Like this...

[crakarjax]

Originally Posted by Johnny_Lamebridge

Just my opinion... but I don't think you can compare the steel bushing and rubber bushing type shafts with one another. Who's to say that the shoulder you're measuring from is the same on both types of shafts?

I think all of these measurements would be best taken from the centre of the LCA shaft. That way, we could accurately compare any type of LCA shaft. Like this...

Very good point, iff the shoulders are indeed different. Anyone have two types of shafts that they can compare?

[jnickell41]

So these will be going on a 1/2 ton '87 R10 so will have the rubber bushings.

The holes are 8.75 inches apart, 4.375 inches from the centerline of the shaft. I have included a picture of the box they came in.

I checked the shafts that came out of these lower control arms and they appear to be the exact same measurements, distance from the ends as well as distance from each other.

Am I missing something here, are the majority of the 1.5 inch measurements I've seen on this site from 72 and older trucks, or 3/4 ton trucks with steel bushings?

Any insight would be greatly appreciated.

[The Rocknrod]

I have a 64 with Steel Bushings, here are my measurements before drilling on a stock unit:

[69gmcc10]

Originally Posted by jnickell41

So these will be going on a 1/2 ton '87 R10 so will have the rubber bushings.

The holes are 8.75 inches apart, 4.375 inches from the centerline of the shaft. I have included a picture of the box they came in.

I checked the shafts that came out of these lower control arms and they appear to be the exact same measurements, distance from the ends as well as distance from each other.

Am I missing something here, are the majority of the 1.5 inch measurements I've seen on this site from 72 and older trucks, or 3/4 ton trucks with steel bushings?

Any insight would be greatly appreciated.

That is one of the things we are trying to figure out right now and why everyone is trying to add as much info as possible. Thanks for adding your information to the thread. Hopefully, with guidance from BMERDOC and others of his caliber on this thread, we can make some sense of things.

[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.

[BMERDOC]

Have you put air in them (cycled them) to see if they settled out correctly?

[SCOTI]

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 made my own upper plates & shifted the mounting holes forward when I did the caster mod for my lowers. I then had to shift them back (drill more holes) when I swapped in the PB lowers.

I would make new uppers or re-drill the holes accordingly to keep the bag as straight as possible @ ride height.

[crakarjax]

Originally Posted by BMERDOC

Have you put air in them (cycled them) to see if they settled out correctly?

No, my crossmember isn't installed yet so I'm just mocking things up. I contoured my lower cups though and they're inthe spot where they are going to land.

Yeah, shifting them forward seems like the best option at this point -- I should have waited on painting the plates! I wish I had just fabbed up some plates for the lower control arms now though, because then I could put the bags wherever I wanted them. I did find a cutaway of the SS bags though and the bumpstop looks like it covers the entirety of the bag top/bottom, being a non-issue.

[69gmcc10]

got myself my new Moog (part# k6147) lower shafts in the mail today! When I set them up against the old shafts I noticed something was not right!

The old shafts are longer than the new shafts!

[69gmcc10]

New shafts

[69gmcc10]

Old Shafts

[69gmcc10]

And side by side...

[69gmcc10]

In the photos yo will notice the overall length of the shafts themselves are the same, bot with and without the caps on. When comparing the end of just the shafts, not the knurling or lip but over all length of the entire rod, the index hole on both shafts are the same. It appears that there was a redesign to the new shafts at some point and they decreased the length of the large diameter (by 3/8" on each end to be exact) and used a longer rubber grommet to cover the distance. This is why we are getting different dimensions when comparing old shafts to new shafts, they are designed slightly differently, but keep and maintain the same geometry as the old shafts.

One of the biggest telling factors are the rubber seals/grommets used, there is a large difference between the old and new.

[The Rocknrod]

Can you just buy those new grommets somewhere?

[69gmcc10]

I don't know, I haven't looked, sorry.

[Ezzz]

About to give this mod a go this weekend. One thing I'm wondering is why it's necessary to remove and replace the original riveted stud on the saddle that serves to locate the shaft? If we're drilling the same size locating hole on the shaft won't the same locator work?

[jjzepplin]

I reused it.