Torque Boxes Broken?

[Dr. Teeth]

Hi all. I just got a 91 Stang and noticed that as i am driving if I thump the throttle the car seems 'squirrelly,' like its trying to dog-track momentarily. I had this same problem with a Chevelle, and after spending $1000 on new rear end suspension compnents, it was a $9 motor mount. Before I make this same mistake again, could anyone tell me what happens to these cars when these Torque Boxes go bad? thanks.


Brian.

 

[85GTlover]

Why don't you look on the car for damage to the boxes?

 

[Schlodes]

What would badly damaged lower torque boxes look like?

 

[85GTlover]

Look at the part that holds your back springs. Where that connects to your body is the torque box(the other end is on rear end) that is the lower control arm. The uppers are the other things that attach to the rearend, more in the middle and up under the car that is also considered torque boxes. If they are bent, twisted apart in any way.

 

[keith black]

check the upper and lowers for play, my sleeves inside the rubber bushings where the bolts goes through were cracked in half, my car did the same dog tracking. i pulled them off put in some mac upper and lowers with urethanes car rides stiff but launches real nice and straight now!

 

[Badlilstang]

I had a simliar problem while back and I had cracked the hell out of my tq boxes and moved one of them an inch and a half out of place. I had a guy that worked at ASP named Richard rebuild them.. He took out my bolt in subframes and cut out my tq boxes completely.. he then fabricated new tq boxes onto my subframes then welded them back in place.. ive gone high 9s on them with no problem... If I remember right it cost me like 500$. There are all kinds of ways to repair tq boxes if thats your problem.

 

[Scott W]

Did you buy a notch? If so, check to make sure the cross brace behind the rear seat isn't loose. Its only held on with 4 tack welds. mine ripped apart and the car was really loose, didn't feel like the same car at all, after looking all over the car, i found the problem.

 

[Dr. Teeth]

No, its a hatchback. I got under there and tried to jiggle stuff around, although nothing really happened. I could not see any damage to the boxes but from what you guys say i'll be there is. I'm gonna try the engine mount first, which I know is bad, then if that doesn't do it I'll rip into the bushings/boxes, but I hate dealing with those bolts.

 

[stangbear427]

They arent that bad. The main thing you need to not kill yourself (both literally and figuratively) in the driveway is a pair of tall jackstands and a good floorjack. An air ratchet and a small compressor frost the cake. If the torque boxes are cracked, you'll probably be getting a good clunking noise from the back every time you take off, especially if they are bad enough to effect the handling like you describe. Just to eliminate the question of the mounts, don't get the stock rubber ones again. Spend the extra $ on the Prothane or Energy Suspension engine/tranny mount kits. If it still does it with them in there, you KNOW it's something else. You can get bolt in torque box replacements for a couple hundred dollars, about $100 a pair for uppers or lowers. They are best welded in, but mine have been bolted in for well over a year with no issues. Good luck!

ps congrats on the '91 GT... I'm partial to that on myself.

 

[87'GTstang]

You can basically just look under there and if you see them cracked then you'll know your problem off hand. If not, then you'll have to go more in-depth and look at the bushings. All it takes is inspection. I think there are types of weld-in subframe connectors that attatch in a way to help relieve stress from the torque boxes. I'm not sure if all subframe connectors are like that but I do know they make some that are for that problem.

 

[stangbear427]

Most weld in full length sub frame connectors do weld to the jacking plate, which is part of the lower torque box. However, that isn't where the boxes tend to crack so it doesn't help much. The overall stiffening of the chassis in general does, but they don't negate the need for torque box reinforcements when the damage is already done. You're right though, if it's the boxes it should be pretty obvious, especially if it's that squirrely on the run.

 

[Dr. Teeth]

I'll try those mounts first, and I have done those control arm bolts enough times to know that you're just trying to make me feel better. I usually grind off the heads and bash them through, then replace with hardened replacements. Never got one out that was usable. Anyways, I'll update when I find the prob. Thanks again for all the input!


Brian.

 

[stangbear427]

Huh. Really? I've pulled the rears out of several of these cars, changed the whole suspension in mine twice, my wifes once, and never pulled a bolt out that I couldn't put back in. Get a can of Blaster, and soak it all down the night before or something. They shouldn't be that difficult. The main thing is having room to work reasonably comfortable, and getting the order of operations right. Either way, good luck. I hope it's your mounts!

 

[Dr. Teeth]

Update

After all that, it ends up being the left upper control arm bushing, all squished out the side. Oh well, now I have an excuse to order performance control arms!!!

 

[stangbear427]

I like the way you think! Just beware of the domino affect: I thought a blown quad shock was a good excuse to replace all six shocks at once- performance!, which led to "may as well do lowering springs too" then "better do c/c plates with springs" to "may as well do boxed uppers and lowers back there while it's open" to "may as well urethane bush the whole suspension while it's apart" to "all this won't do much good without some bracing, like a 4pt K-member brace, strut tower brace, and subframes" yadda yadda. Since I was out of work at the time, it was pretty a extreme financial outcome over a $20 blown shock.

Here's a question for you: what do you like better, dental floss or the water pick?