Upper rear control arm bushing help
 

Guys, I went for a drive in my Chevelle last weekend, weather was great here. Picked up the boy from baseball practice, and we all three (me, the wife, and Brandon) went to dinner. Car ran great, except I had a serpentine belt issue, but that’s totally unrelated to this question. Got on it a couple good times, taking it to rev limiter in first twice, which is 7800. Car is putting 616 hp/525 tq to tires currently on a poorly done street tune, again that’s a different sermon, for a different day.
Anyhoo, I get car back home, washed, dried, and back up on lift in shop where it stays with a cover on it, and I’m doing a visual underneath the car. To my surprise, my upper rear control arm bushings at the 12-bolt are both destroyed. I’m talking virtually gone. Looks like they exploded? They were poly, along with all my other rear control arm bushings. My question here is: I’m guessing I’m binding back there, but where? I’ve searched the net for similiar situations and I can’t find anybody dealing with this. My rear control arms are CPP, and of course it’s all new stuff. Is this a setup issue? Anybody ever see this before? I did read over on TeamChevelle that maybe I should go rubber bushings up top, if I’m running poly lowers, to keep from binding. I just don’t understand the binding part. When I was building the car, in mock-up stage, I cycled the rear through its motion up and down, with coil overs off, and just bare housing, and it sure didn’t feel like anything was binding. What am I missing here?

Well guys, after doing more research today, it turns out that with the A-body rear suspension setup, which is an inverted 4-link, you can not run a poly bushing in the upper rear control arm bushings. There is a inherent amount of binding that is naturally in this type of system due to the two different arcs that the uppers/lower arms are moving in, and there MUST be a small amount of movement at the upper rear joint due to binding. Using poly bushings in all 4 pivot points will not allow any movement, which is why my upper bushings literally exploded. I will either go rubber bushings, or to a “Johnny joint” type setup on my rear upper pivot at the 12 bolt, which will allow a tiny amount of movement. Hope this helps somebody out there.

So I guess I wont chime in then , glad to see you got it figured out on your own .cheers

That situation sounds a little more extreme than most. The cool thing is, we have the solution in the Roto-Joint arms.

http://umiperformance.com/catalog/in...roducts_id=372

Let me know if we can help.

thanks

Well...I have the Roto-joints with my CPP tubular uppers...which came with the poly bushings for the 12 bolt by the way... After much reading up on other similiar situations, apparently the Roto-joint simply allows for misalignment, but doesn’t allow movement front to back. The Johnny-Joints (at the 12 bolt pivot) are supposedly going to allow the pivot to have a small amount of movement front to back?
Or just perhaps this was just a scenario of big power and sticky tires?
Any input here from you guys would be awesome!

Hey Scott,

Ridetech just released a press in version of the patented R-Joint specifically for the A & G Body rearends. They will allow the needed movement getting rid of the roll bind and stiction and do not require any maintenance. The RTX-10 material we use never needs lubricated and the spring loaded design eliminates the need for adjustment. We also offer a simple tool that makes removal and installation super easy.



R-Joint
https://www.ridetech.com/images/thum...0/11227298.png
https://www.ridetech.com/products/r-...988-gm-g-body/

Installation Tool
https://www.ridetech.com/images/thum...0/85000011.png
https://www.ridetech.com/products/ac...pper-bushings/

Let me know if I can help you with anything,

Jody Glenn
Ridetech Sales Specialist
https://www.ridetech.com/
812-481-4751
[email protected]

Scott, I recently removed the rubber bushings from my axle housing and replaced them with the Ridetech R Joint cartridges and I can attest that they remove a lot of bind from articulation while still holding the housing where it should be. I see no reason why you would want front to back movement at this pivot point.

My lifting of the inside rear tire on corner entry issue went away after swapping out the rubber for R-Joints.

Personally, I'd find a way to put some sort of solid but smoothly articulating attachment at all 8 points of the triangulated rear suspension. Ridetech R-Joints or UMI Roto-Joints would be my first two choices.

A-bodies are awesome because they come with factory 4-links. With the right bushings, shocks and springs A-bodies and G-Bodies can ride as well as a new Mercedes-Benz. If you chose an A-Body rather than a Leaf Spring-equipped F-Body, you are ahead of the game.

The original design relies on flex within rubber bushings for articulation. Many upgrade kits substitute poly which is a fundamental error. During bind, either the poly bushing fails or the frame side mount flexes. Some have created braces for the frame side mounts to resolve the flex -- which is compounding the mistake rather than addressing the original issues and meeting true performance goals:

A-Body/G-Body Rear Suspension Goals:
-- Improve Articulation.
-- Harness modern power potential and available traction.
-- Minimize flex (rubber bushings)
-- Eliminate premature wear (rubber bushings)
-- Eliminate stiction (old seized-up rubber bushings and poly).
-- Prevent inducement of binding (Poly bushings)
-- Eliminate the need or for frame mount bracing
-- Prevent inducement of noise (poly bushings squeak)
-- Minimize maintenance (poly bushings need greasing)

For RideTech, the fix is to replace all link points with R-Joints. They articulate exceptionally well without flex or noise -- and they are self-lubricating, so virtually maintenance free. Ride quality is truly awesome when combined with our shocks an a good set of tires (within usage date)

You can see how it all works together in our TruLink kit, or replace just the upper axle bushings. You can always upgrade in stages. Our heavy duty arms are an important piece of the puzzle.
Here's a pic of the complete kit. See more details here: TruLink Rear Suspension for A-Body

https://www.ridetech.com/images/thum...eb_52lw-3r.png

Thanks for lookin'
Steve

Lance, I appreciate your insight here. I am looking into a R Joint setup to help with the binding I’m experiencing.

Steve, I’ll touch base in the next couple days. Thank you!