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Repairing crushed rails / dented floor

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Old 10-11-18, 08:28 AM
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Repairing crushed rails / dented floor

Repairing crushed frame rails and dented floor pan.

So i've reached the part of my restoration where its time to try and straighten out the floor pan. Evidently someone has in the past jacked it up using the rails underneath leading to crushed rails and a floor pan.

The sills I can bend back and tap into place with a sheet metal hammer, the rails themselves I think I can probably get close enough with a slide hammer and various attachments. Its the floor pan that's making me scratch my head.
As you can see by the below photos, the whole rail itself has been pushed upwards into the floor pan.
I've had a half hearted attempt to knock them out with a block of wood and a lump hammer from the inside, but its not done anything, anyone have any thoughts on how to go about it.

I realise that I could drill out all the spot welds and take off the rails which would then make it easy to beat the floorpan flat, but I want to avoid that if at all possible.

Some pics, they aren't the worse I've seen but not the best either. Weirdly the UK car seem to get some side reinforcement rails that I've not seen any pics of on your US cars.



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Old 10-11-18, 01:00 PM
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Those are the worst I've seen.
Get that air chisel sharpened and try something like this.
https://www.rx7club.com/2nd-generati...rails-1088241/
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Old 10-11-18, 02:25 PM
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I've seen way worse on MX5s. But in fairness they're made of butter.

I have some frame rails, but in order to make them fit I'll have to cut a slot out of one side of them, you can see down at the bottom of the pics where the UK cars have a lateral rail to reinforce the chassis. Unfortunately I think with that cut out they won't have the rigidity to pull the floor flat again.

Not sure why I'd need an air chisel as I want to avoid cutting the rails out if possible, if I do decide to cut them out then I'd probably take the nuclear option which would be this:
https://www.norotors.com/index.php?topic=17423.0
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Old 10-11-18, 03:36 PM
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Originally Posted by theDevilX View Post
I realise that I could drill out all the spot welds and take off the rails which would then make it easy to beat the floorpan flat, but I want to avoid that if at all possible.
I'd consider this your best option. It's the least invasive opening move and gives you the widest range of options with minimal commitment.
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Old 10-11-18, 04:18 PM
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Originally Posted by clokker View Post
I'd consider this your best option. It's the least invasive opening move and gives you the widest range of options with minimal commitment.
I am edging towards this now, I feel like I'm only asking people because I know what I have to do and am just looking for a reason not to do it!
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Old 10-11-18, 05:03 PM
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The car's gonna want what the car's gonna want...it has a very felinesque disregard for your feelings.
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Old 10-15-18, 12:14 PM
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Yes I've noticed that about most my cars.

I've stripped out the dash and carpet to get at it and I'm now certain its a rail off job, I've no idea how whoever did this managed it.




The damage to the sound damping material was done by me while attempting to beat it flat with a big block of wood and an even bigger hammer. To no avail.
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Old 10-16-18, 05:06 PM
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Originally Posted by theDevilX View Post
The damage to the sound damping material was done by me while attempting to beat it flat with a big block of wood and an even bigger hammer. To no avail.
Yeah, the panel is too bouncy for that approach.
I think you'll have to press it-overpress it to allow for springback- to get closer to flat.

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Old 10-17-18, 01:36 AM
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Are you trying to get the floor flat between the door and the trans tunnel?
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Old 10-17-18, 03:43 AM
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Yes, or at least flatter than it is now.

If you look at the other side, the floor from the trans tunnel is basically flat up to the rail.
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Old 10-17-18, 06:28 AM
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Originally Posted by theDevilX View Post
Yes, or at least flatter than it is now.

If you look at the other side, the floor from the trans tunnel is basically flat up to the rail.
I might be misunderstanding you, but the line you have marked with yellow is a highpoint between the trans tunnel and door, it's not supposed to be flat.
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Old 10-17-18, 07:31 AM
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Originally Posted by Pettersen View Post
I might be misunderstanding you, but the line you have marked with yellow is a highpoint between the trans tunnel and door, it's not supposed to be flat.
Yeah I misunderstood the problem when I made that pic. It turned out that it was bent up on the tunnel side, but is supposed to have a bit of a bend from the pinch weld side.

I had to cut out the bottoms of the rails to get rid of some rigidity but I've managed to get it about right. With the frames gone, excessive hammering and big wooden block did the trick.




Not the easiest to see but you can see how both sides of the car now match.

Now I just need to decide how to fix the frame, either remove it entirely and make up a new piece, or possible go through floor box section style.
Oh and go back around with a hammer and dolly to straighten out the floor pan stiffening grooves.

Last edited by theDevilX; 10-17-18 at 07:39 AM.
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Old 10-17-18, 08:04 AM
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Nice, but you should realy get a spot weld drill, that way you could remove the rail, straighten it out and reweld it.

I use one of theese, and it's amazing.

https://www.ebay.com/itm/Spotweld-Cu...wNN:rk:13:pf:0


And i just bought weld thru primer for my project, so i can go full Binky..
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Old 10-17-18, 09:07 AM
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Originally Posted by Pettersen View Post
Nice, but you should realy get a spot weld drill, that way you could remove the rail, straighten it out and reweld it.

I use one of theese, and it's amazing.

https://www.ebay.com/itm/Spotweld-Cu...wNN:rk:13:pf:0


And i just bought weld thru primer for my project, so i can go full Binky..
I should be able to straighten it in situ. But it may end out coming yet, i'm also going full Binky with a cup of tea and some thinking.

That spot weld drill looks nice, but no way am I waiting for shipment from America to the UK. I'll get something local if I do.
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Old 10-17-18, 10:52 AM
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Probably more likely to find it local in uk compared to Norway 😅
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Old 10-17-18, 11:00 AM
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Probably more likely to find it local in uk compared to Norway 😅
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Old 10-17-18, 11:39 AM
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Originally Posted by TRRAPLN View Post
Those are the worst I've seen.
Get that air chisel sharpened and try something like this.
https://www.rx7club.com/2nd-generati...rails-1088241/

You dont want to see our 1st gen E Production chassis then. :P
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Old 10-23-18, 11:51 PM
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Originally Posted by TRRAPLN View Post
Those are the worst I've seen.
Get that air chisel sharpened and try something like this.
https://www.rx7club.com/2nd-generati...rails-1088241/
you should see mine...
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Old 10-24-18, 12:36 PM
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I will no longer bring my FC into tire shops. They have crushed my rails every time. It's a 30 year old car and can't afford more damage.
I thought about refusing to have them put it on a lift and only jack the sub frame but I can't relie on that unless I supervising the process.
I am resolved to removing tire/wheels and bringing them to them.

Last edited by TRRAPLN; 10-24-18 at 12:39 PM. Reason: sp
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Old 10-24-18, 02:01 PM
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I did this, it worked surprisingly well


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Old 10-24-18, 03:25 PM
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Why not just drill an anchor into the floor concrete floor, put an eye-bolt with a steel plate on the top through the floor of the car, attach the two with chain, and then lift the car by the jacking points with a couple jacks or a lift?

That should pull the floor back down and it will be easier to weld a few bolt holes up from the topside of the floor rather than weld upside down.
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Old 10-24-18, 03:43 PM
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Thanks for all the assistance, but as per my earlier post I've got the floor as flat as it was from factory. I'm just prepping up to weld in new rails.
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Old 10-30-18, 02:18 PM
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dang thats a lot of grinding to be doing on your back, props
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