Chevy Impala SS Forum banner

1 - 3 of 3 Posts

·
Registered
Joined
·
405 Posts
Discussion Starter #1
Hello, I have my rear end out for rebuild and want to change my upper and lower control arm bushings while I have room to do so as well as maybe put some chassis paint on some areas where the vehicle needs it (surface rust) where the shocks and springs sit at top. I’ve been reading about upper adjustable and lower extended control arms. I’m still deciding if I want to spend the money. I understand from some posts that upper bushings will wear from some type of binding because the geometry changes from stock forward positioning of the rear diff. Posts also believe the connections (Clevis positioning etc. can help). Idk, I want NO reason to have to change worn bushing parts up in there for a long time. Also, I want to broken parts up in there later earlier than stock parts will last. I also read that stock upper control arms may be better than aftermarket because they need to flex a bit. I know performance control arms remedy wheel hopping and lateral movement (tire rub around corners). I understand for racing purposes people want rigid suspension there but my car is not a race car. It has a stock engine with 3:73 gears in it and a cold air intake. That’s all. I’d like to have my wheels centered in the wheel well. That would be nice. I just want to weigh my options here. Should I put extended control arms upper and lower while I’m here with the diff out?

Questions:
1. Is it a must I need to have upper adjustable control arms to use extended lowers for pinion angle? I’m guessing yes. My car is lowered 2 inches (With springs) in the rear as it sits with 24 inch rims.
2. Do they sell a weldable boxing kit like I’ve seen on Summit racing website for older cars “for our 94-96 Impala and Caprices?“ has anyone boxed theirs? I have yet to find a post on the forum.
3. If I do put adjustable upper and extended lower control arms to center my wheel, whats the chances I will have “binding issues” or “chewed up rubber parts” on my uppers? That’s my fear. I dont drag race but do get some corners sometimes for fun. I don’t want to burn rubber here and there, and find I need to change these upper bushings “poly or whatever” in a couple years. I’d kind of rather box my stocks, put new bushings in Upper and lower and see many miles to come with a wheel that sits forward a little bit. As for wheel hop, I’ve experienced that too. My tire grabbed my wheel once on the lower front corner and bent it. Dont get me wrong but this Binding and rubber chewing up thing is the reason I am staying away from that decision (binding issues). Am I not seeing something clearly or am I over reacting? I want a solution that is as good or better than factory for my daily driver type semi stock street car. I feel like wheel hop and lateral movement fixes is the trade off for replacing bushing in such a hard place to get to. What’s the General fix to this Bushing bind? Has it been fixed yet? Do people run rubber vs poly? Do the control arms accept stock bushings? Is Metco a good option?

4. Do these after market upper and lower kits put more stress on the mounting tabs that are welded to the vehicle Since they are more rigid? Is it possible I could break mine in the future?

5. which bushings wear and tear on the uppers? On the diff? On the body side?

6. How long will a set of Metco upper adjustable and lower extended billet last me? They say no other mods are required. I’ve read the drive shaft does not need to be extended and read it does. Can I get some feedback on this one? Will my stock driveshaft suit me with light driving until I get the shaft? I’d probably get it don’t as soon as air get my car back on the road but will driving it to a shop break something on the tranny spline side? Does this all depend on what kit I use?

Im interested in this kit. >>>>>>>>>>>>>>1994-1996 Chevrolet Impala Parts | A657503 | 1994-96 Chevrolet Full size Models - Billet Rear Control Arm Set (0.75 Extended Length) | Classic Industries

Thanks.
 

Attachments

·
Registered
Joined
·
8,131 Posts
There's a lot going on down there, so I'll just contribute as I go. You've clearly been doing the search thing = kudos. Perhaps I'll add to the keywords you can research further. Confirming the set up in my sig: 1st gen extended METCO upper / lowers, all poly bushings.

Hello, I have my rear end out for rebuild and want to change my upper and lower control arm bushings while I have room to do so as well as maybe put some chassis paint on some areas where the vehicle needs it (surface rust) where the shocks and springs sit at top. I’ve been reading about upper adjustable and lower extended control arms. I’m still deciding if I want to spend the money.
With my HO bar I knew I was in for at LEAST some manner of new aftermarket arms, so whatever the added difference in cost from regular to extended lenth was the upcharge to move 5/8-3/4" for visuals. Boxing the oem (detailed below) was an option, but not my preferred route. HTH
I understand from some posts that upper bushings will wear from some type of binding because the geometry changes from stock forward positioning of the rear diff.
You're mixing 2 things. Keep them separate. 1.) Even the orig. uppers 'bind' as a result of torsional stress as the car corners at extreme angle. Stock softer rubber bushings yield more so this --> usually <-- isn't an issue for the life of the car. 2.) Enter (much) stiffer aftermarket stab bars that DEMAND aftermarket arms, and all the guys figure the perfect time to upgrade to 'stiffer' poly bushings all around for improved road feel and presumed less wind-up and hopping during accel. Great, but now the binding uppers becomes an issue. For those who don't require extendeds then many have learned just to get nice new stiff lowers to handle the stab bar, and don't even bother with touching the uppers.

Posts also believe the connections (Clevis positioning etc. can help).
Yes, offset clevis is intended to address and relieve torsional bind. Great feature, and any suspension upgrade is valued in light of what the car will be used for - garage queen, driver, strip, full race.....
Idk, I want NO reason to have to change worn bushing parts up in there for a long time. Also, I want to broken parts up in there later earlier than stock parts will last. I also read that stock upper control arms may be better than aftermarket because they need to flex a bit.
Aha. So you caught that already. lol
I know performance control arms remedy wheel hopping and lateral movement (tire rub around corners).
Again, you've been doing your homework. Yes, harder bushings; less sideplay; less lateral slip. And it helps rubbing with big wheels/big tires.
I understand for racing purposes people want rigid suspension there but my car is not a race car. It has a stock engine with 3:73 gears in it and a cold air intake. That’s all. I’d like to have my wheels centered in the wheel well. That would be nice. I just want to weigh my options here. Should I put extended control arms upper and lower while I’m here with the diff out?
100% up to you. But never a better time than with the rear out. Lots of combinations, *leave rubber in the axle ears or replace, *leave the uppers as-is v. new ones if not doing extendeds......

Questions:
1. Is it a must I need to have upper adjustable control arms to use extended lowers for pinion angle?
Yes. No way to retain proper pinion angle using orig. length upper with extended lower. Not logical.
I’m guessing yes. My car is lowered 2 inches (With springs) in the rear as it sits with 24 inch rims.
Just personal opinion, but with those big wheels the car should NEVER be cornered at a speed even close to where torsional bind of a control arm becomes an issue.
2. Do they sell a weldable boxing kit like I’ve seen on Summit racing website for older cars “for our 94-96 Impala and Caprices?“
Err?? You can answer that on your own. If not showing an app for last gen, then the prior box gen used the same control arm(s). I've seen the weldable plug barstock, and there are manufacturer 'bolt-in' pieces for a stock lower too. It may have even been a TSB or assembly line add depending on suspension option.
has anyone boxed theirs? I have yet to find a post on the forum.
I've seen numerous. Don't use 'Relevance' in your search. Use 'Date'. Put " " around your keywords to focus results better.
3. If I do put adjustable upper and extended lower control arms to center my wheel, whats the chances I will have “binding issues” or “chewed up rubber parts” on my uppers? That’s my fear. I dont drag race but do get some corners sometimes for fun. I don’t want to burn rubber here and there, and find I need to change these upper bushings “poly or whatever” in a couple years. I’d kind of rather box my stocks, put new bushings in Upper and lower and see many miles to come with a wheel that sits forward a little bit. As for wheel hop, I’ve experienced that too. My tire grabbed my wheel once on the lower front corner and bent it. Dont get me wrong but this Binding and rubber chewing up thing is the reason I am staying away from that decision (binding issues). Am I not seeing something clearly or am I over reacting? I want a solution that is as good or better than factory for my daily driver type semi stock street car. I feel like wheel hop and lateral movement fixes is the trade off for replacing bushing in such a hard place to get to. What’s the General fix to this Bushing bind? Has it been fixed yet? Do people run rubber vs poly? Do the control arms accept stock bushings? Is Metco a good option?
Al addressed otherwise.
4. Do these after market upper and lower kits put more stress on the mounting tabs that are welded to the vehicle Since they are more rigid? Is it possible I could break mine in the future?
Never heard of that.
5. which bushings wear and tear on the uppers? On the diff? On the body side?
Addressed above.
6. How long will a set of Metco upper adjustable and lower extended billet last me?
Mine are 20 years old, 60k. Original dia. rubber, 10" widened stock wheel.
They say no other mods are required. I’ve read the drive shaft does not need to be extended and read it does.
You're perfectly correct. All the debate focuses on the extent of reduced DS's spline's load bearing on the output shaft. Factors include extent of power adders, each aftermarket brand's "extension" whether 1/2", 5/8" or full "3/4" to true center.
Can I get some feedback on this one? Will my stock driveshaft suit me with light driving until I get the shaft?
You have nearly no power adders and you're citing 'light driving'. So the answer for me in similar conditions was "No". But, you also state you like to, "get into corners" and then there's the big wheels, and those been shown to cause increased driveline stress even on their own, so now the answer changes to "Yes". If electing to get a lengthened DS your options are something like Denny's with their great reputation, or the 'Crown Vic Composite Cop' DS, which is 3/4" longer than our stock length.
I’d probably get it don’t as soon as air get my car back on the road but will driving it to a shop break something on the tranny spline side?
Pretty likely not. But why are you driving anything to a shop to change a DS?
Does this all depend on what kit I use?
Addressed above.

Im interested in this kit. >>>>>>>>>>>>>>1994-1996 Chevrolet Impala Parts | A657503 | 1994-96 Chevrolet Full size Models - Billet Rear Control Arm Set (0.75 Extended Length) | Classic Industries
Looks fine. I have the 1st gen of that on my SS, and that same version of regular length on my Cady.
Thanks.
It was a pleasure. Orderly, well thought out presentation, easily followed train of thought, a lot of time and respect used in posting = v. painless read. And great title for future search. Thank you!
 

·
Registered
Joined
·
485 Posts
If you look at how the entire rear suspension is designed to move, changes in pinion angle on braking and acceleration and why the upper control arm could bind; you'll see that the cosmetic effect of how GM made the wheel well openings has no effect at all. Goofy cosmetics but no performance liability. Extended control arms of all sizes only make all of the above work less well. Yes cosmetic advantage with big functional disadvantage. The binding is easiest to address, a set of Dick Miller Racing braces that bolt onto the attachment points at the frame of the upper + lower control arm. About $125 US. Any poly bushing after market LCA will allow the HO bar to work the way it's designed to without binding. As will any after market UCA with the DMR braces. 24" wheels? By far the biggest performance liability for ride, handling, braking and wear and tear. A chassis designed for 15" wheels where 17" wheels were showing some liabilities. The above addresses those liabilities for 17's, maybe 18's; after that, and I quote "Just personal opinion, but with those big wheels the car should NEVER be cornered at a speed even close to where torsional bind of a control arm becomes an issue. "
 
1 - 3 of 3 Posts
Top