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How to straighten a bent subframe

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Old May 21, 2012 | 04:55 AM
  #1  
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How to straighten a bent subframe

Before we bought our car, someone using a garage lift to service the car had placed the lift points incorrectly under the front passenger subframe. The weight of the car bent the bottom of the fender and compressed the sheet metal subframe slightly. This damage is minor, and is only cosmetic. One cannot see the damage unless you lay on the ground and look up at the floor pan. I straightened out the bottom of the fender, but have not been able to figure out how to straighten out the stamped subframe piece. The floor pan is not bent. The car has been like this since before we bought it in 2006, and the only reason to repair the damage is to be able to compete in shows where the undercarrage is checked. It may be beyond my abilities, and it may be best to take it to a body shop? Any ideas will be appreciated. Thanks in advance. Charles
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Old May 21, 2012 | 06:15 AM
  #2  
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Re: How to straighten a bent subframe

If you have access to a dent puller you can fix this. Put the car up in the air, and put either a slide hammer, or a stud puller on it, and proceed to straighten. Use a bit of metal glaze and some sanding, then primer and paint to match.
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Old May 21, 2012 | 06:35 AM
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Re: How to straighten a bent subframe

Does it vibrate at around 60? Get an aliment. I hope the chassis don't twist that easy.
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Old May 21, 2012 | 06:52 AM
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Re: How to straighten a bent subframe

Originally Posted by 89rs454
Does it vibrate at around 60? Get an aliment. I hope the chassis don't twist that easy.
What you said doesn't make sense. Someone jacked up his car where the front fender meets the subframe. It damaged the boxed end of the subframe. An alignment wont fix that. And it wont give you a vibration. He's talking about showing his car at car shows....
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Old May 21, 2012 | 07:13 AM
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Re: How to straighten a bent subframe

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Old May 21, 2012 | 07:39 AM
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Re: How to straighten a bent subframe

Originally Posted by calamitascamaro
What you said doesn't make sense. Someone jacked up his car where the front fender meets the subframe. It damaged the boxed end of the subframe. An alignment wont fix that. And it wont give you a vibration. He's talking about showing his car at car shows....
If someone jacked his car up where it wasn't right on the jack points could twist your chassis yes. I wish you the best of luck.
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Old May 21, 2012 | 07:43 AM
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From: Putnam Valley, NY
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Re: How to straighten a bent subframe

Originally Posted by 89rs454
If someone jacked his car up where it wasn't right on the jack points could twist your chassis yes. I wish you the best of luck.
Again, he says in the OP that it is cosmetic in nature. So an alignment wont fix the damage. I wish you the best of luck as well.
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Old May 21, 2012 | 07:55 AM
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From: Putnam Valley, NY
Car: 1992 RS 6spd
Engine: Carbed 357c.i.
Transmission: Built T56
Axle/Gears: Soon to be Strange S60
Re: How to straighten a bent subframe

Again, in his OP, he said he is posting to fix the "cosmetic damage" to go to car shows where they judge the undercarriage of the vehicle in the over score. Which would be the point of posting his problem. Read before you speak. And chill with the language it's not needed or wanted on this site.

Last edited by 88txiroc; May 21, 2012 at 11:18 AM.
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Old May 21, 2012 | 07:55 AM
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Re: How to straighten a bent subframe

Please enlighten me, what exactly are the jacking points? There are none, these fricken subframes are made of thin multilayer sheets and they dent very very easily when jacking up the car.

The flap where the fender bolts down can be fixed with some hammering/dollying most likely although it'll never be like new. Almost all these cars have that damage and a bowed out fender relative to the door.

A dent puller may help you clean up the underside of your frame, or you can weld a plate on it as a jacking reinforcement. Or fab some box steel SFCs and mount them outward against the pinch area, that should conceal most of the damage left after hammering.



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Old May 21, 2012 | 08:02 AM
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From: Putnam Valley, NY
Car: 1992 RS 6spd
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Transmission: Built T56
Axle/Gears: Soon to be Strange S60
Re: How to straighten a bent subframe

I use wood in between the jack and the vehicle, when the vehicle goes up, the wood compresses and almost always prevents damage under the vehicle. There may be no "right" place to lift these cars, but the absolute wrong place is the fender mounting tab lol.
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Old May 21, 2012 | 08:04 AM
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Re: How to straighten a bent subframe

..

Last edited by calamitascamaro; May 21, 2012 at 11:37 AM.
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Old May 21, 2012 | 08:11 AM
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From: Putnam Valley, NY
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Re: How to straighten a bent subframe

..

Last edited by calamitascamaro; May 21, 2012 at 11:37 AM.
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Old May 21, 2012 | 08:16 AM
  #13  
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Re: How to straighten a bent subframe

This does create a problem bent fender tabs is bad cause it weakens the metal causing rust which will spread out to the floors that happened on my 89 gta i had

Last edited by 88txiroc; May 21, 2012 at 11:20 AM.
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Old May 21, 2012 | 08:20 AM
  #14  
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Re: How to straighten a bent subframe

One thing u can do also is unbolt the fender bolt that goes into the rocker then cut off that piece that got bent an replace it with new sheet metal, then drill a hole an nut an bolt the fender back alot of my buddies done this on there 3rd gen i havent seen one 3rd gen with the fender tabs perfectly straight They were always either bent inwards or outwards
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Old May 21, 2012 | 08:21 AM
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Re: How to straighten a bent subframe

Originally Posted by soarestransam
This does create a problem bent fender tabs is bad cause it weakens the metal causing rust which will spread out to the floors that happened on my 89 gta i had
I bet it does, it must be bad.
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Old May 21, 2012 | 09:34 AM
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Re: How to straighten a bent subframe

before he owned it !!!! now wants to fix it for cosmetic reasons please go back up and read what he says before posting unless your doing it to be just agrevating . lets recap

no drivability issue
only cosmetic
fixing for judges to give more points in shows
boxed portion of subframe dented in alittle no structure damage just cosmetic
did i forget anything

mine are bad too but since i will be fixing mine for myself not for judges i'm just going to box them back in. the previous owner of mine high sided it on a tree or something crushed the rocker in and the bottom door sill and the passenger side floor i fixed the door sill and the floor and the rocker but the subframe from when he pulled the car a chain has a rip in it and is dented pretty bad but as for yours i would do a dent puller the weld type weld the pins on and pull the box back into shape and then clean up and paint might hve to use some filler to smooth but for a show car it's the stuff you have to do.

Last edited by 88txiroc; May 21, 2012 at 11:20 AM.
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Old May 21, 2012 | 09:39 AM
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Re: How to straighten a bent subframe

Originally Posted by jhainer
before he owned it !!!! now wants to fix it for cosmetic reasons please go back up and read what he says before posting unless your doing it to be just agrevating . lets recap

no drivability issue
only cosmetic
fixing for judges to give more points in shows
boxed portion of subframe dented in alittle no structure damage just cosmetic
did i forget anything
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Old May 21, 2012 | 11:25 AM
  #18  
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Re: How to straighten a bent subframe

All,

I have cleaned this thread up. Please do NOT quote others that are bypassing the swear filter. Just report it and I will deal with it.

89rs,

Consider this your one and only warning. If you continue to try to bypass the filter, I will ban you and your IP. Please do not make it come to that. This is a family site. Keep it clean. Saying that you were "drinking" is not an excuse.

88txiroc
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Old May 21, 2012 | 04:06 PM
  #19  
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Re: How to straighten a bent subframe

Originally Posted by calamitascamaro
If you have access to a dent puller you can fix this. Put the car up in the air, and put either a slide hammer, or a stud puller on it, and proceed to straighten. Use a bit of metal glaze and some sanding, then primer and paint to match.
Thanks for the great information. The damage is very minor, and on a DD I would not bother to repair it. No bowing of the fender, and the bottom edge of the fender straightened out almost perfectly. The worse part of the fender was trying to match the paint.

I took the car to a body shop today who we have used for years. They said that they will use the technique you described above, and make a repair that will not be noticeable. We pulled up this tread, and the folks at the body shop got a pretty good laugh reading some of the posts.

Charles
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Old May 21, 2012 | 07:07 PM
  #20  
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From: Putnam Valley, NY
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Transmission: Built T56
Axle/Gears: Soon to be Strange S60
Re: How to straighten a bent subframe

Originally Posted by 86WS6
Thanks for the great information. The damage is very minor, and on a DD I would not bother to repair it. No bowing of the fender, and the bottom edge of the fender straightened out almost perfectly. The worse part of the fender was trying to match the paint.

I took the car to a body shop today who we have used for years. They said that they will use the technique you described above, and make a repair that will not be noticeable. We pulled up this tread, and the folks at the body shop got a pretty good laugh reading some of the posts.

Charles
Glad I could help man. Have a good one.
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Old May 21, 2012 | 07:42 PM
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Re: How to straighten a bent subframe

That's exactly what happened to mine,I'm having new fenders and a new front bumper cover installed on my car and the body shop had a problem removing the right fender because of that.He has to do some metal work under there on both sides to make it right,if not the fenders will not install correctly.
I don't know when it happened but this had to be done with a shop lift,maybe back when I had a new exhaust system or new tires put on long'long time ago.I didn't know my car had rust and now that has to be fixed.

Last edited by mantaguy; May 21, 2012 at 07:46 PM.
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