rear control arm question

[rellik god]

i boxed my lower rear control arms my question is should i box the uppers also ?

[87gtVIC]

Nice work. Looks great.


I cannot give you a answer but I don't see why it would hurt.

My question for you is did you tack the sway bar spacers in place?

[pantera77]

I would. Less flex is always better. I assume you did poly bushings as well?

[gadget73]

less flex isn't always better. Problem with the fucked up geometry we have, you need some flex and deflection for it to work. With boxed arms and poly bushings, its very likely to bind or rip a mount out of the frame. I've seen people do this with Mustangs and usually it binds until it rips the mount loose. Mustangs have shorter arms and have more trouble with binding, but its still the same basic design we got.

[87gtVIC]

less flex isn't always better. Problem with the fucked up geometry we have, you need some flex and deflection for it to work. With boxed arms and poly bushings, its very likely to bind or rip a mount out of the frame. I've seen people do this with Mustangs and usually it binds until it rips the mount loose. Mustangs have shorter arms and have more trouble with binding, but its still the same basic design we got.

Those guys steer clear of full poly bushing swaps. They only do the uppers or lowers and only one side and keep the others side rubber (or something strange like that) to avoid binding everything up.

[rellik god]

pictures

[rellik god]

[rellik god]

got this info from Maximum Motorsports' web site

Stop Torque-box Damage
Torque-box damage is often blamed on "too much power". Wrong! It is usually the result of metal fatigue caused by a poor rear lower control arm bushing design.

It is commonly believed that as long as the rear lower control arm bushings do not deflect, they must be okay. Not true. Any up and down suspension movement causes the rear lower control arms to not only rotate on their pivots, but also to change their angularity, relative to their chassis-end and axle-end mounts. If the rear lower control arm bushings are not designed to accommodate this change in angularity, the suspension will tend to bind up and not move freely. That hurts traction, and can damage the chassis-side mounts (the lower torque-boxes) for the rear lower control arms. While the repeated binding of suspension movement may not harm the steel of the axle-housing bracket because it is quite thick, the thin sheet metal of the chassis mounts will fatigue and eventually fail.

[gadget73]

Those guys steer clear of full poly bushing swaps. They only do the uppers or lowers and only one side and keep the others side rubber (or something strange like that) to avoid binding everything up.

yeah, it isn't pretty. Threaded rod with heim joints on the end is really the way to go if you can swing it. That gives you a fully adjustable control arm length and the heim joints allow free range of motion without any chance of binding. My own solution is just leaving the arms alone. Between my grandpa driving and the amount of twist possible with a C channel arm, it ought to be OK.

[BerniniCaCO3]

Hey rellikgod: I bought poly bushings, also the police lower control arms, 2 years ago and ran out of time/ chickened out on installing them in the rears.

Without a proper lift and shop + impact tools, how intimidating is it to get the control arms out of there? Do I need to use a torch and do I need to drop the fuel tank?

What do you think a welder would charge to box them (and is it worth)?

[rellik god]

got my arms from junk yard so i could do work on them with out rushing to get back on car.not to intimidating any rusted bolt you should use penatrating oil or wd 40 and last resort heat. ill be using map gas to heat things up if needed
dont need to drop the fuel tank.dont know about welder cost.

[BerniniCaCO3]

thanks! I'm sure I can find a local community college or art college kid who can tack on a plate for me. I've only done a bit of welding, a while ago, and have no equipment...

I'll be doing the upper control arm bushings too; do I want to box them in, as well?

[gadget73]

I personally wouldn't box the arms at all, but thats just me. I don't do anything that would benefit from more rigidity on the arms, and I do not ever want to deal with the arm mounts being ripped out because of it. If you want the rear to stay in place better, fabricate a watts link or a panhard bar. Both will give you much better lateral location than any amount of modification to the stock control arms will offer.