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Frame rail carnage. Fix or forget.

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Guys, sorry for the rush here but I need a quick answer on how to proceed from someone experienced in this area.

I just got done stripping the tar based undercoating from the floor pans and was planning on simply applying some POR-15, but now I'm not sure whether to go ahead with that as planned ignoring the damage, or attempt to repair the damaged/dented frame rails first since POR is kind of a permanent thing.

The damage can be seen in the pics below. It looks like it was probably done by either or both the PO and mechanics putting the car on a lift, as well as a possible road hazard on the driver's side(caved in floor pan when I got it).

The dilemma is that I need to address this as quickly as possible since I'm down to bare metal. The car is stored outside in a car port, and I live 3 blocks from the ocean, so ocean fog and moisture is a concern. The good news is that I have yet to find a spec of rust, and I'd like to keep it that way.

So a few questions:

Do I need to worry about this from a structural standpoint, or is it mainly cosmetic and I can proceed as planned and just POR over it? All I plan on using the car for besides regular on road usage is aggressive mountain driving and an occasional autocross or track day event. I don't plan on ever having a motor with more than 200-250HP

What would be the easiest way to address this if that is the recommended route? I have pondered the following in order of extremity:

A) POR over it now, and strip it off later to fix if I change plans on HP or intended use, assuming it's not a structural threat at the moment. Is this even feasible? This stuff sounds permanent and hard to strip.

B) Drill some holes from the top and use a punch to straighten it out. possibly using some heat. I have some concerns about breaking loose spot welds if I do this.

C) Have a sheet metal guy bend me a piece that I can weld over the top that extends forward tying it into the T/C box. Note: I'm not a welder myself, but I can learn.......not sure if this is the best project to learn on....

d) Obtain replacement frame rails and replace the whole damn thing, and tie it into the rear subframe while I'm at it.....Probably extreme overkill....

I should have just left the damn undercoating on and found something better to do while waiting for parts to come in............Hindsight is 20-20. :)

Adam

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Go get an alignment and be sure everything is in its place. If it is, the worry is gone, unless strictly for resale. The Metal Ready will take care of any minor oxidation that takes place in the next day or so. You'll want to etch the metal anyway, prior to PORing.

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The car is disassembled at the moment but the alignment was fine prior to disassembly in looking at the tires that were on there for 20K miles or so when I purchased the car . This is old damage, not new. If I choose to make the repair, the car could be sitting as it is for a few weeks. If that's the route I choose to go, would coating it with some WD-40 or some grease hold me until then?

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Minor, nearly inconsequential (unless other bumps and waves make you think the car was hit and subsequently straightened out.) problem. At least you have frame rails and floors with no rust!!!

I seriously doubt it will affect resale value.

Metal Ready and POR, then forget about it.

Steve

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90% or more of the Zs left on the road today will show similar "damage" - both of mine do. Too many years, too many opportunities for the tire monkeys to jack up the car in the wrong spot. (Yes, I can say that safely, I was a tire monkey for many years. A good one, I hope, but a tire monkey none the less.)

I agree with nwcubsman, if you know the car is alignable as it is now, POR it and forget it.

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Minor, nearly inconsequential (unless other bumps and waves make you think the car was hit and subsequently straightened out.) problem. At least you have frame rails and floors with no rust!!!

I seriously doubt it will affect resale value.

Metal Ready and POR, then forget about it.

Steve

I second that!

I wish the rails on my 1970 were that nice!

You could get one of those weld on stud dent pullers and pull them back into better shape. That would be better than drilling holes if you really want to fix them.

If it really bothers you.

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After just replacing my right rail I would say there is no damage to yours that needs any more attention then you are giving it. This is one of those places where you have to think is it broke, ie not preforming what it is designed to do, if it is then fix it if not move on.

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Mine shows similar damage, this is why I never let anyone fool around with my car that is not some sort of Z-expert. They will just throw a jack anywhere they please and bend that sheet metal up without a second thought.

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So the metal looks pretty darn good and that is a big plus. If time wasn't as big of a deal I would personally straighten out as much as possible and then do what fellow club member ED did... Weld some strengthening steel on top of them... He did a very nice job with his. Just like Arne mentioned, mine shows similar damage too (ala "Tire Monkeys").

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If you are truly concerned with the appearance. Check out Bad Dog Parts. They make frame rails. The 280 Rails will fit over the existing 280 Rails and are heavier steel. Check and see if the 240 Rails are the same. If so, just place over the existing dented rails and mig weld into place. From the tone of your heading I was expecting that you found a big rust problem, not a few dings.

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Great reasons to install and clearly identify the single point jacking points from Baddogparts.com...

Will

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Adam - It doesn't seem all that bad. If you dont have any alignment problems, visable cracks or rust through, it is only cosmetic. Years down the road if you plan further work, replace them then. I'm replacing mine now, along with the rockers, floor pans and rear quarters. These cars are about the easiest ones I've done as far as replacing these parts go. The availability of the parts needed is something I'm not used to. That's something for all of us to consider. How long before replacement panels are NLA?

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Thanks for the words of advice guys. I decided to go forward with the POR for now. My main worry was that this was more than cosmetic. There are no cracks and absolutely no rust anywhere that I can find. Woohoo! In fact, under the tar undercoating, there was a pretty stubborn layer of primer that had to be stripped off as well.

Here's a tip for the rest of you, don't attempt to refinish the bottom of your car unless you have your car on a rotisserie. :) I spent the last two days on my back stripping the undercoating and finish off with tar chips, paint, dust, sparks and wire wheel bristles ricocheting off my face and this was only the floor pans. Unfortunately, I have to do this in sections because of the difficulty doing this from underneath. My arms and shoulders are so damn sore. I think I have a total of 15hrs into it at this point and it's ready for the coat of POR-15.

Next comes the rear section, then the wheel wells, and lastly the front frame rails........:rolleyes:

Happy Easter! :bunny: :bunny: :bunny:

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i just had this same dilemma and decided to fix it . My rails are rust free and I am doing a complete resto. I thought this won't be much work.:stupid: Actually it wasn't that bad. i cut a hole in the floor to access the frame and beat the frame back out. And it took some pretty good shots to get the dent out. You won't get it done by drilling holes and using a punch. You need a 3lb hammer and a big flat dolly for it to come out right. So you have to cut a big enough hole for the dolly to fit in. I am a perfectionist which usely cost me time and money, but to each is own.

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Wow, it looks like the whole rail is bent up, not just bent in. Did pounding it tear any of the spot welds loose? I'm still considering giving it a go before I lay down the POR sometime this week.

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I must agree with what others have said . I have similar damage under my Z . I think this kind of damage is from driving off a curb and hi centering. At least this is what mine seems to be . I replaced the floor on my passenger side but it was because the floor was cracked length wise along the floor rail. I would just treat the metal and POR it . Gary

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yes it did actually cause me to do some welding. but as you see, my damage was worse then yours. I still think that to fix yours right you will have to can-opener your floor like i did to get a flat piece of metal on it. I used 1/4" steel bar and had to hit hard and a lot to starighten her out. But you can't tell there is any damage at all now. You should see what i did to my frame rail in the engine compartment. Yes, my car was hit in the front end at one time but that damage you see was probably from a curb or jack

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I think I might be able to straighten it by opening the floor like you did, supporting the frame rail on a jack stand with a piece of flat steel between the rail and the jack stand, and then beating the fracking wizz out of it from above. However, the damage to my rails is so far forward that I'm afraid I might damage the dash while trying to swing the hammer with enough force to do any good. Perhaps I should just live with it........ If I do, and you guys ever see it in person and say "Nice car, what happened to you frame rail?", I just might blow a gasket. LOL

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Ok, I'm done with the POR on the floor panels. This stuff goes on way thin and self levels very well, even when upside down. I'm a bit worried that it's too thin but I'm not sure how I would have laid it on any thicker. Is a second coat feasible or even recommended? Also, I totally overestimated how much it would take to cover this area. I ladeled out 9oz and only used like 3.5oz so the rest was wasted. Anyway, it turned out great. Here are some pics just after I finished cleaning up. I have a few black dots on my face...I guess they're gonna be there a while.....LOL

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Hey Freckles :eek: - You should have applied a few more coats after it was set up a little. I usually put what is left over in a jar of the appropriate size (to limit the amount of air left in the jar) and then find something else to paint within the next few days. It's a little too pricey to waste. Sometimes it will skin over in the jar if you don't get back to it in time, but you just break through the skin to get to the POR that hasn't set up.

PS- Looks good though.

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Hey Freckles :eek: - You should have applied a few more coats after it was set up a little. I usually put what is left over in a jar of the appropriate size (to limit the amount of air left in the jar) and then find something else to paint within the next few days. It's a little too pricey to waste. Sometimes it will skin over in the jar if you don't get back to it in time, but you just break through the skin to get to the POR that hasn't set up.

PS- Looks good though.

The only issue with that theory is every time is "Skins" over, the POR thickens. You need to use the POR solvent to thin it back out. I've resealed my containers numerous times and each time the POR gets thicker and thicker.

It does still harden but self leveling and how much area the remainder will cover become another issue.

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The car is disassembled at the moment but the alignment was fine prior to disassembly in looking at the tires that were on there for 20K miles or so when I purchased the car . This is old damage, not new. If I choose to make the repair, the car could be sitting as it is for a few weeks. If that's the route I choose to go, would coating it with some WD-40 or some grease hold me until then?

Whatever you do...do not cote it in WD-40 or grease! This will effect any coating you put over it later! Even if you you wax and grease remover and metal prep, it will not get out what has soaked into the metal. Adhesion problems!

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