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Rear control arm replacement


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Hello. Been a while since I last posted. So I completely rebuilt the front end of my 70 last fall and I can't believe haw bad my car was handling before ! LOL. I have been driving trucks my whole life and thought the car handled okay before, for a big heavy . What a huge difference. Now I am taking care of the rear end. I installed Moog rear springs and KYB gas-a-just shocks a few years ago. I am going to replace the control arms with heavy duty "boxed"  ( 3c FAB racing ) and install a rear sway bar off a 70 GTO I got on Craigs list. The control arms are pretty straight forward. I was going to install control arm braces ( Massive brand on Ebay ). Stupid question here but I don't remember see any type of "stock" control arm braces already installed on my car ? Unless I just missed it ? From the picture it looks like they bolt from top of rear end to the fwd lower control arm. Do they bolt on thru the control arm mounting boss to the frame ? It looks like there is plenty of room for the sway bar to mount to the trailing edge of the lower control arm. I would appreciate any help here. Thanks.

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Hey Crewdog, I'm not familiar with the brace that your referring to but here's a photo of my upgrade, boxed lowers with poly bushings and sway bar from Summit.

post-732-0-82943500-1430954983_thumb.jpg

post-732-0-30101600-1430955146_thumb.jpg

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Murry did you do that right on the ground? this old body dont want to do that kind of stuff anymore. I have lower boxed control arms and sway bar and spring spacers and upper spring cousions I may wait untill my buddy gets his lift in to do them.

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I know my 70 Monte and 70 El Camino has the brace that run from the upper control arm bolt down to the lower control arm bolt, and I want to say the 72 had it as well. What the brace does is add strength to the cross member above the rear end. A stock brace is flat stock two a hole in each end and a bend on the end. I know there is a post in the engine tech talking about mufflers which shows a overhead view of where the brace mounts at, on my work laptop and with its IE can't copy and paste the thread.

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I'd love to see a pic of that Robert............I just reviewed my Assembly manual for 72 and don't show that support brace.

 

Steve, that's the setup I have, 1" spring spacer, cargo coils with air shocks at 25 lbs. Yes, I installed with jack stands when I was doing my brake job. What are you going to change?

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Thanks Robert, I just found the brace listed in the PST catalog with the kit! Great info, was not aware of such a support . Thanks!

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The support braces are to help make the frame more ridged during hard cornering/acceleration.  Can't remember if they were there on a stock car and simply stamped steel.

If you are doing the lower arms it just makes sense to do these at the same time as one project.  All the aftermarket suspension guys make them.  Would likely match them to the lowers arms you choose as Rob did with the BMR ones above.

 

Currectrac, Hotchkis, Speedtech Global West, BMR, Spohn, PST, Metco, Detroit speed  and alike all make the control arms and I believe the braces.

 

Dan 

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I'd love to see a pic of that Robert............I just reviewed my Assembly manual for 72 and don't show that support brace.

 

Steve, that's the setup I have, 1" spring spacer, cargo coils with air shocks at 25 lbs. Yes, I installed with jack stands when I was doing my brake job. What are you going to change?

Going to change the lower control arm and add the sway bar (stock ones) I alread have the air shocks and put cargo coils in a couple years ago but the upper spring cousions were bad so I just made a couple up to get me by, going to add 1" spring spacers just so I dont really have to run much air in the shocks unless I have to.

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Wow, upgrading all that can get pricey!!!!

I would like to do front after tightening up the rear last tear, but I'll be living with the new stock front end for a while it seems

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Murry did you do that right on the ground? this old body dont want to do that kind of stuff anymore. I have lower boxed control arms and sway bar and spring spacers and upper spring cousions I may wait untill my buddy gets his lift in to do them.

 

One thing I would do is not tighten the sway bar till the car has it's full weight on the suspension...they actually say that about all the suspension parts but things like the sway bar that is hard bolted to different movable parts is important. Best to have them resting with the weight because if you didn't and tightened them with no weight on them you will preload them and when the car is lowered it will have tension on the suspension with the car not even in motion.

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I know that about the bushings but the sway bar is in a fixed position so I didnt think that would matter much.

 

It is but there will a little play in the bolt holes. I still would not want to tighten them down with the suspension hanging...if so when you lower the car and weight is applied the bar may have wanted to seat itself but now if the bolts are tight it won't be able to. It will transmit a possible twist to the other arm sort of like a torsion bar. Am I over thinking this...maybe so  :D. I know when I did my suspension I played around with it and made things better and worse...now everything is better. Mine is far from stock, only thing stock on it is the front upper and lower control arms.  

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hey thats my pic...lol..yeah while your back there workinyou might as well replace em..will help in the handling department. cant wait to drive mine and see how it drives

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I just put my rear axle UMI upper arms on and tightened everything down in the air, then got it on the ground and loosened it all up again, then torqued it all back down .there is some preload on it when it was all loosened up,as the car did settle a little more.Now upper and lower match.

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Hey Murphy. I read your post and saw your pics what type of 1 in spacer is that? It looks like you have put it on the bottom of the spring, and do cargo springs handle additional weight better than standard springs?

John S

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It's a 1" aluminum spacer by SPC. Go to Summit and search for coil spring spacers. SPC makes several different sizes...........As far as the cargo springs, they were put on the car by the previous owner about 15 yrs ago so I can't compare the difference to standard springs. My understanding is that they are a bit stiffer as to withstand extra weight.

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The cargo coils are designed to handle extra weight without having a stiffer ride, and thats exactly what they do. They are a very good upgrade if your planning on adding any extra weight. I load mine right up for camping and they work just fime. I'll be pulling a small trailer this year and they should work just fine. I'm going to be putting the same spacer as he has just so I can run less air in shocks.

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