I’ve done the caster mod should I also get upper control arms?

[Slowguy]

I did the caster mod early on. I also cupped the lower control arms and did lower spindles with bags. Needless to say it’s much lower than stock. I’m guessing at least 5-6” inches at ride height.

I also assume I’ll need to space out the upper ca’s quite a bit even at ride height to get a good camber adjustment. Been researching and it’s not a good idea to stack many shims? If not, and I need aftermarket longer upper control arms for a lowered ride, will this mess with the caster since I already did the caster mod?

[HO455]

Which style of caster modification did you do? As far as your upper control arm questions they can only be answered by the manufacturer of the arm. Each company has a different take on what they want to accomplish with their control arm.
This link will take you to the front suspension part of my Burban project. There is more information on the next page as well. For even more information try posting your question on the suspension part of the forum.
Good luck.

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

[Slowguy]

I don't recall the exact thread but it is basically the most common caster mod listed somewhere here on the forum. I think I did it exactly as you described in post 248 of your thread. I don't assume I will have any caster issues provided I keep the stock upper control arms. But, as things go, I did more reading and see that many say it's almost mandatory to go with a longer, aftermarket upper control arm when lowering with bags. That said, however, it doesn't appear you did on your build? If that is correct, how did you compensate for camber when going to bags and lower ca cups while still keeping the stock upper ca?

[HO455]

You are correct I am using factory upper control arms. To do so all depends on how low you want to go. The lowered ride height (not aired out) is the important part.
After I modified the lower control arms, did the caster modification to the lower control arm shaft, and installed all the new components I reassembled the front end I put the truck up on the alignment rack and started playing with the alignment. As I am bagged I decided on a ride height on all four corners and tried to bring the alignment in to the specifications I wanted. After several attempts and slightly raising the ride height in the front I was able to get a satisfactory alignment. I used some thick washers to replace some of the shims. There are plenty of threads for the nuts to secure the upper control arm and the amount of shims on top of the washers I made is acceptable.
The other benefit that I didn't realize at the time but it came to light not long afterwards is I have very little bump steer. If I were to lower the front end ride height another 1 inch (or more) and lower the bump stops correspondingly I would experience bump steer. And the upper control arm shaft bolts would be then be too short.
I don't have an actual measurement of how much my Burban has been dropped as it was bagged when I got it. (It was worn out and hacked to boot so it was a bit of a white knuckle experience crossing railroad tracks. ) But it looks like this at ride height. (See gratuitous photo of truck at picturesque highway view point )
And if funds don't allow upper control arms now. You can do what I did for now and later on when conditions are right install some different uppers and go lower. But when/if you do just have a plan for dealing with bump steer and your truck will be a joy to drive.

Disclosure time: I did have fairly unlimited access to an alignment rack to do this. Which was nice but I could have done it in my driveway with a couple hundred dollars worth of tools. There are videos on the interweb explaining how to do the alignment yourself with low buck tools. At the very least you need to find a shop that deals with race cars and understands what is going on not just what the book/ computer says. Or find a local racer (roundy round, rally, auto crosser or road racer) with the tools who wants to earn some cash helping align the truck.

[Slowguy]

Thanks for all that info on your experiences. You have a point. Might as well give it a try now with the stock uppers. Nothing to lose. If I don’t like it or it doesn’t work out as planned, then I’ll just change it out. I don’t mind spending the money where it’s needed. I just try to figure out where’s the best place to put it right now.

Very nice ride btw! It looks super clean.

One thing I might add is that (at least for right now) I’ll have some giant 22” transit wheels installed. Flipping the centers in the rear to change backspacing but the diameter may affect how everything works together especially when compared to a more “normal” diameter wheel (something like an 18)

[HO455]

Thank you for the kind words and keep us posted on what you do.