Cross brace

Chadly

Chadly

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Has anyone ever removed the brace behind the reae seat? Got some ideas kicking around in my head but not sure about any ill effects from removing that brace.
 
you could always add bracing around it, to make up for the loss of the cross brace.

Honestly I dont think it can do all that much, Guys tccoa have a rear strut tower brace that would probably be sufficent for support.
 
All three cars I parted that brace was broken.... so I bet you could remove it, but them being broken also says that there is a lot of flex in the chassis....
 
While I'm not an engineer or an expert on this type of thing, I'll offer these thoughts on the subject. The brace wouldn't have been designed into the body if it wasn't necessary. There are two 'bulkheads' that give strength and rigidity to the Mark's body. The front one is the firewall area. Think about where the brace is and what is attached to the body below the brace. While that part of the body has a substantial amount of bracing in that area, the cross brace behind the rear seat is part or the structural 'cage' that gives strength and rigidity to the Marks' unibody. By removing that cross brace, you will also take some structural strength out of that area. While possibly not immediately noticable, I think that it's removal would allow the body to flex more and become 'loose'. Over a period of time, this may affect things like how well the car handles, how the doors seal the cabin, and if your car is subject hard use, the body may even develope a permanent twist. My opinion would be that this brace structurally is too important to remove. Anyone else?
 
i wouldnt take it off.........

heck i tried adding SC L braces but they dont fit........lol

im gonna get that rear shock brace from tccoa for mine.
 
I'm doing a seat swap this summer. Going to get SC seats with the 40/60 rear fold down. I'm planning on cutting out the cross brace and welding in a stronger square tube frame. Looking into possibly extending an X from the top and connecting the rear towers? I want to keep it lite as possible and tight to the top so I can use all the trunk space. That won't be for a while, but I let you know how it goes in case anybody is thinking of swapping seats. I'll take measurements and maybe make a square framed X brace. If there is that much flex back there that the Xs are breaking, it sounds like the cars could use the extra stiffness. Man, these projects really pile up quick.:eek:
 
Agree that it could cause 'loosening' of the body over time, but I'd vote for chucking it.

How do the Tbirds/Cougars with fold-down rear seats get away with no brace?

After reading that link, could a broken brace be the cause of an annoying rattling? Our 94 has a weird rattle coming from just behind the seat - might be a great thing for me to check out when the wifey gets home.
 
Those MN-12 chassis with folding rear seats likely have some other type of stiffening / bracing in that area.

Annoying rattling in the trunk area could be a bunch of things; snapped brace, worn shock mounts, loose package tray etc. All easy enough to check.
 
Same here. I replaced mine long ago with some really heavy duty solid mounts.
 
What about adding subframe connectors to the mark? Anyone done this? SHO & Mustang guys add them for rigidity in the chassis.
 
Roadboss did... I'm leary on doing it though... don't know if I want to change the dynamics of the chassis being as I'm not an engineer lol...
 
the SC's with fold down seats got the L braces, regular MN12's got a big V brace, havent seen an X brace on an MN12 so it might only be on the Marks........ive also seen some MN12s at the yard with nothing behind the seat :eek:
 
Just discovered my cross brace is snapped also at the same place as Blue on Blues, but only one break.
The Mark was making a irritating shimmy type sound at various highway speeds.
Guess I could try a Abe Lincoln repair job and use JB weld, but dont think that would hold for long.
I have added the 1/8 Addco sway bar and front support braces from Super Coupe. Those could change the bearing loads on the X brace.

Gen 1, 85000 boring miles.

David
 
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No, best thing to do is get it welded up, then do something along the lines of what I did. I was lucky to have jamie97lsc near by to weld mine up real nice.
 
If these cross braces are breaking, that would be an indication that there is a lot of stress in that area and the factory braces aren't capable of handling the stress. For this reason I would recommend that the braces not be removed. I would also suggest that they be reinforced; especially if if you're going to be pushing the car near it's limits, both in straight line as well as road course situations Yes; that means on the street as well as race tracks.
 
Woof47 said:
Ask the guys that found broken braces and fixed them if they noticed any difference.
Click to expand...

I only noticed a difference from a noise perspective, but then I've never driven hard enough. Guess circuit / auto X racing would tell more. If the Mark is flexy back there, a nice rear shock tower brace would work well - be simple to make too. (if you have some fabbing skills)
 
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