Replacing floor panels on '68 (repost) [Archive] - Classic Cougar Forums

: Replacing floor panels on '68 (repost)



VMacKenzie
October 28th, 2009, 10:52 AM
Not sure where the thread went I started a couple days ago but the jist of it was how feasible would it be to replace floor panels & torque boxes on a '68 without removing the drivetrain, mainly because I don't have the time or $$$ to jump into a full restoration or engine rebuild (doesn't need rebuilt that bad).

There were a couple replies when I saw it last, wasn't on the internet yesterday though, but one saying it would be difficult because of the drivetrain weight stressing the body and affecting alignment. I am thinking about instead of removing the drivetrain to instead hook up a cherry picker toward the back of the engine and disconnecting the motor mounts and lifting up on it enough to relieve most if not all of the weight. I would use a jackstand under the trans and undo its mount as well. Not sure if this would suffice or if having the car not level would make alignment measurements difficult or not.

Someone posted a link to this website with a writeup of floor panel repair which was very helpful http://www.theclassiccougarnetwork.com/tccn2/index.html

If anyone else remembers my thread and what you posted it would be great to hear from you again. I'm most concerned about body alignment and maintaining strutural integrity through the process. With the torque boxes being deteriorated and soft floor around the frame rail I suspect the body isn't perfectly true as it sits, which will make this project a little more challenging.

Thanks again everyone,

Vaughn

Art
October 28th, 2009, 11:46 AM
Do one side at a time, leave the doors and fenders on to check the alignment as you go.

VMacKenzie
October 28th, 2009, 12:18 PM
Another thing I meant to mention is some of the cancer thru the floor is only reachable behind the fender, a little above where your toes would be when sitting on the passenger side. I would have to remove that fender. Does that mean I'm getting into replacing some of the firewall?

I'll likely remove my fenders since I'm going to be rebuilding the front end at the same time, although I will likely leave them on to do the torque boxes and floor pan area, then remove them. With the fenders off I would like to clean up the old delaminating undercoating which I'm sure traps water making it more rust prone. I'm going to remove the undercoating as much as I can and rustproof/prime/prep and do whatever coating I need to in those areas that will be durable and minimize the chances of this happening again.

Speaking of torque boxes are there any writeups about replacing them? Interestingly most of the floorpan rust is on the passenger size, but the torque box on that side is in much better shape than the one on the driver side.

Art
October 28th, 2009, 12:38 PM
Another thing I meant to mention is some of the cancer thru the floor is only reachable behind the fender, a little above where your toes would be when sitting on the passenger side. I would have to remove that fender. Does that mean I'm getting into replacing some of the firewall?From bottom to top, floorpan-toeboard-firewall.


I'll likely remove my fenders since I'm going to be rebuilding the front end at the same time, although I will likely leave them on to do the torque boxes and floor pan area, then remove them. With the fenders off I would like to clean up the old delaminating undercoating which I'm sure traps water making it more rust prone. I'm going to remove the undercoating as much as I can and rustproof/prime/prep and do whatever coating I need to in those areas that will be durable and minimize the chances of this happening again.
Torque box should be replaced when the floor pan is removed.


Speaking of torque boxes are there any writeups about replacing them? Interestingly most of the floorpan rust is on the passenger size, but the torque box on that side is in much better shape than the one on the driver side.Self-explanatory once you have the new piece in front of you and you've cut the old one out. Sometimes just the lower torquebox plate is rusted and that's all you have to replace. HERE (http://rides.webshots.com/photo/1199254070060268584OHOEyk) is the RS torquebox install on my Mustang (same part as a Cougar).

Just remember, grind the metal shiny before you attempt to weld. Trying to weld through paint, rust and corrosion is difficult and leaves a weak weld.

VMacKenzie
October 28th, 2009, 02:00 PM
Thanks for your input Art. I just crawled under the Cougar again and you're right the torque boxes only need patch repair on the lower side, should be pretty easy to do.

I like what you did with the frame rails on your Mustang, extending them to the back. . . when I finally do a full teardown and ground up that's one of the things I want to do as well.

Vaughn

VMacKenzie
November 30th, 2009, 09:33 PM
Kicking this back up, getting ready to order panels to work on the floor and have a couple more questions that I haven't found good info for:

I read that you don't need to weld every inch of seam, just spot all the way around with about 25-30% of the distance in welds then "seal the rest up with a good sealer." So what would be a good sealer? Wouldn't the best long-term solution be to fully weld it?

Secondly there is undercoat all over the bottom, which is deteriorating and pretty well done for. I am thinking to strip as much of this off as I can (that's going to be a job!) but what would be recommended to finish the bottom side with starting at bare metal? How about going Por-15 Metal Ready then primer then chassis black to finally some kind of undercoat (or skip the undercoating and use dynamat for noise suppression)? The car WILL get driven in the rain (but not snow), quite a bit I expect, and I want to make it as weather-resistant and durable as I can.

Last question, in the past I've seen support bars or subframe extenders for body strengthening and I'd like to do that while I'm at it, but after a quick search I couldn't find anything. Would doing this be worthwhile for someone who wants a solid tight-feeling car? Is this hard to do?

I am probably going to order panels from Ken's Cougars since they seem to be the only place that has toeboards.

Thanks again, Vaughn

woodsnake
November 30th, 2009, 10:32 PM
I find it hard to believe that Kens has anything unique in the area of sheet metal.
That being said, support who you like.
I'd use a wire wheel on a drill to remove the old stuff around where you are going to repair, and then when you are done maybe some chassis black or similar product designed for bare metal.

VMacKenzie
November 30th, 2009, 10:46 PM
Thanks woodsnake. I looked at other sites like WCCC, Mustangs Unlimited, and I think John's Classic Cougars and only find the floor pans and no toe boards unless I'm missing something. Not too concerned about who I order from other than getting what I need at a reasonable price with good customer service.

VMacKenzie
December 1st, 2009, 12:37 AM
I see some floor pans are 19 gauge, and some are 22. . . probably want the 19 gauge!

tbm3fan
December 1st, 2009, 01:00 AM
I read that you don't need to weld every inch of seam, just spot all the way around with about 25-30% of the distance in welds then "seal the rest up with a good sealer." So what would be a good sealer? Wouldn't the best long-term solution be to fully weld it?



I don't know where you read or saw that but I would definitely weld around the entire repair skipping a few inches at a time to avoid heat build up in the panel and then grind the welds smooth. Are you doing a butt repair or lap? After that two good coats of epoxy primer would be enough assuming you have a water tight interior i.e. no leaky cowl, no leaky heater core and no missing A/C drip tube under the heater if A/C equipped.

Art
December 1st, 2009, 02:18 AM
The best way I've found to get rid of old undercoating is by using a small propane torch, a metal putty knife, and a steel brush.
With the torch, get an area of undercoating (around 6 x 6") hot. Hot enough to start smoking, then scrape it off with the putty knife.
Heat the same area again except this time brush the remainder off with the wire brush.
Keep on going stripping and brushing small areas until you finish. Any remaining can be wiped off with mineral spirits and a rag.

The metal doesn't get hot enough to scorch the paint underneath.

Fuzor two part seam sealer is the best. The 3M fast and firm will crack and fall out in time.

VMacKenzie
December 1st, 2009, 10:15 AM
tbm3fan yep I'd definitely skip around and take a few "laps" when welding vs. going in a continuous run. I checked out the cowl area with a flashlight and luckily no rust there, definitely no leaks. Not sure about the AC hose, AC hasn't worked in years.

Art I was just thinking about doing it that way because I took decades worth of old peeling paint layers of an old house that way and it worked pretty well.

Vaughn

SeanD
December 1st, 2009, 04:38 PM
If you think about it, the whole car is welded together with just spot welds. I only welded my floors on about every 4 inches. I made sure the new/old surfaces were flat against each other, then welded, then used a solvent-based seam sealer to caulk around the perimeter and in all the crevices. Then I rolled on a layer of epoxy primer, dynamat, then used a pro-quality rubberized undercoat for the bottom of the car. That stuff in a spray can is almost useless. I also drive my car everyday.

Here is after welding:
http://i42.photobucket.com/albums/e301/seanpaintsflames/DSCN2189.jpg

As far as support, I had the back wheels on the ground, jackstands under the back ends of the frame rails, and a jackstand under the radiator support where the strut rods bolt through. Then I took the hood, fenders, and doors off. It all went back together fine.

VMacKenzie
December 1st, 2009, 10:30 PM
Sean did you do this with the drivetrain in the car?

BuntyRit73
December 3rd, 2009, 05:05 PM
looked in the search section and on daves restos about replacing a passenger front floor pan in my mk1 escort, im pretty clear on it now but was just wondering is it best to seam weld the chasis rail back on from underneath or plug weld it from the top and also my seat box thing is in perfect condition so can i just leave that intact and weld the floor pan slightly forward of this?



cheers guys

xr7g428
December 3rd, 2009, 05:14 PM
Buntyrit is a spammer for a Russian bride web site. Please ignore.

jcbingcougar
December 3rd, 2009, 07:39 PM
Buntyrit is a spammer for a Russian bride web site. Please ignore.Bill, Don't be so quick to tell people to ignore. What if a guy was looking for a Russian bride?

xr7g428
December 3rd, 2009, 11:07 PM
LOL! Doh! What was I thinking...

SeanD
December 6th, 2009, 06:32 AM
Sean did you do this with the drivetrain in the car?

Yes. I pulled it in the garage and took it apart Friday afternoon, and was driving it around the neighborhood without doors and a frontend the next week, I think- after suspension updates.

woodsnake
December 6th, 2009, 07:58 AM
I'm still looking for Russian brides! What was the name of that site?

adam 138
December 6th, 2009, 09:30 AM
I did a set of pans in a 65 mustang. I cut out the old pans leaving a inch lip then using self taping screws screwed the new pan to the old every two or so inchs so it would be flush. Then I removed the screws one at a time and using a mig welded up the holes ( its like spot welding) everything fit geat and flush. The doors and drive train were on the car.

VMacKenzie
December 7th, 2009, 12:29 AM
I did a set of pans in a 65 mustang. I cut out the old pans leaving a inch lip then using self taping screws screwed the new pan to the old every two or so inchs so it would be flush. Then I removed the screws one at a time and using a mig welded up the holes ( its like spot welding) everything fit geat and flush. The doors and drive train were on the car.

That's a cool idea, I think I'll give your idea a try.

This week's plan is to get the car up on jackstands and start peeling off undercoating, then I'll have a good idea what pieces I need to order. I have a pretty full week with other stuff but I'm itching to get started on it.

indiana xr7g
December 10th, 2009, 06:18 PM
Make sure that when you take out the floor that you dont lose the support of the floor. You may want to support the rockers at a level posistion. Don't jack up the car. If you stress the floor your door gaps will be off. Dont overheat while welding. Use small spot and cool with air blower. (Water cooling makes a mess) If you don't cool it as you go along. Overheating the floor will affect you door gaps. Keep checking your gaps as you continue.

adam 138
December 10th, 2009, 09:55 PM
To keep the warping down move from one side of the pan to the other and front to back welding alittle at a time.

VMacKenzie
December 20th, 2009, 08:53 PM
OK back to the top, started tearing into the Cougar this weekend and have some more questions, especially since I've never done bodywork before. I started with the trunk and attached are some pics with questions edited on them:
http://i113.photobucket.com/albums/n228/VMac822/68%20Cougar/Cougar%20Repair%20and%20Restoration/Trunk1post.jpg?t=1261363922
http://i113.photobucket.com/albums/n228/VMac822/68%20Cougar/Cougar%20Repair%20and%20Restoration/Trunk2post.jpg?t=1261363947
http://i113.photobucket.com/albums/n228/VMac822/68%20Cougar/Cougar%20Repair%20and%20Restoration/Trunk3post.jpg?t=1261363963
http://i113.photobucket.com/albums/n228/VMac822/68%20Cougar/Cougar%20Repair%20and%20Restoration/Trunk4post.jpg?t=1261363987

There is this black tar sealer applied in several places, man how do you remove that if you want to strip and reseal & paint the trunk floor??

Some rust holes are in the back trunk floorpan by the tail panel that look like they'd be a PITA to do, because it's right in the corner and right under a frame piece mounted on the floor. . . has anyone done a repair here before? How do you remove and reinstall that little frame piece?

Luckily there is very little that needs patched in the trunk area, once the prep work is done it shouldn't be too hard to do. I'm guessing I won't need to buy any trunk floor pieces to do it either, just use some small pieces of sheetmetal and work them into place.

Next task is removing fuel tank, and probably rear bumper and valence.

Vaughn

68PUMA
December 20th, 2009, 09:35 PM
You can try using a heatgun and scraper to remove the black tar. The frame piece mounted on the trunk floor is the rear bumper mounting bracket. I'm looking in a '68 Mustang Weld & Sealant Assembly Manual and where the bracket mounts to the taillight panel there are 8 spot welds (4 on each side) per bracket. If you grind the paint off of the flanges on the bracket on top of the trunk floor you should be able to see if there are any spot welds.

VMacKenzie
December 20th, 2009, 10:14 PM
That helps a lot, thanks 68Puma

VMacKenzie
December 30th, 2009, 11:13 PM
So what is the purpose of the black tar?? There's some in places besides seams.

VMacKenzie
January 4th, 2010, 12:03 AM
Made more progress today, removed the rest of the interior (except door panels and dash which I won't be removing) and have a better idea of what I need to fix. A good share of the passenger side pan will need replaced, turned out worse than expected, but that's OK since I was planning to replace most of that side anyway. I found a couple amusing surprises. . . the previous owner had put two floor mats down under the carpet and had attempted a patch repair to the floor with a thick layer of fiberglass. Maybe he gets points for creativity.

Luckily the driver side is in pretty good shape, mostly surface rust that should clean up fine.

On the passenger side the rust runs up behind the padding behind the HVAC box, so the HVAC box will have to come out. That is fine, the gasket at the top feeding to the cowl is mostly gone and cold air blasts in there driving in the winter. Good time to fix that too. That'll be tomorrow or Wednesday's project along with removing the font fenders.

This has all been fun and entertaining, haven't ever torn into a car like this before, my life of vehicular tinkering has been almost entirely mechanical.

Updated more pics--> http://s113.photobucket.com/albums/n228/VMac822/68%20Cougar/Cougar%20Repair%20and%20Restoration/

Vaughn

VMacKenzie
January 6th, 2010, 09:10 PM
More progress, taking the front passenger fender off last night was an all-evening proposition! Bolts spending 42 years in one position don't want to let go easily. I found some ugly bodywork in the process. Sometime in the past someone patched in some replacement sheetmetal in the passenger fender by riveting it over the existing piece and hiding it with bondo. Made a great place for even more rust to build.

The question for me is whether this fender is worth trying to save or find a better replacement, the rear mount bracket is also pretty rusted out at the bottom
http://i113.photobucket.com/albums/n228/VMac822/68%20Cougar/Cougar%20Repair%20and%20Restoration/ChassisDis8.jpg

Can see the double layer patch job here
http://i113.photobucket.com/albums/n228/VMac822/68%20Cougar/Cougar%20Repair%20and%20Restoration/ChassisDis7.jpg

Also found the headlight support structure has major rust, I'm wondering what the best approach would be tackling that
http://i113.photobucket.com/albums/n228/VMac822/68%20Cougar/Cougar%20Repair%20and%20Restoration/ChassisDis6.jpg

Sure is fun finding surprises, I should have suspected as much, how often does someone tear into their project and find less rust and surprises than expected?? ;)

VMacKenzie
January 20th, 2010, 02:05 PM
I have a couple fender questions if anyone is still looking at this thread . . .I'm looking to see what I can do about my passenger side front fender. Does anyone make a lower repair panel for this? I'm not finding anything available. But then if you look at the first picture in the post above of the back side of the fender you can see the structure piece is rusted pretty good too. I'm thinking the best option is just get another fender, what do you think?

Ron67
January 20th, 2010, 04:55 PM
Sure is fun finding surprises, I should have suspected as much, how often does someone tear into their project and find less rust and surprises than expected?? ;)[/QUOTE] I picked my car up little over a year ago the guy said it from cali looked to be in good shape few rust holes in the driver side right under the drivers feet. Took it down to bare metal I was shocked how good of shape it was in just one spot on the body and another place where a dent was fixed. But Im not always this lucky with my finds

68PUMA
January 20th, 2010, 08:08 PM
I have a couple fender questions if anyone is still looking at this thread . . .I'm looking to see what I can do about my passenger side front fender. Does anyone make a lower repair panel for this? I'm not finding anything available.
John's Classic Cougars carries both the left & right lower repair panel: www.johnsclassiccougars.com (http://www.johnsclassiccougars.com) click on "Cougar Sheet Metal" and then scroll down to the bottom of the page. Just FYI, there isn't any picture of the panel. IMO, I believe the fender can be saved.

VMacKenzie
January 20th, 2010, 11:25 PM
Thanks 68 Puma, I'd looked pretty much everywhere else except John's. I did talk to WCCC today though and they will sell the rear half of a used fender for a good price, that way I'll have the back support piece since mine is pretty rotted.

Ron67 I hear ya. . . I'm afraid of what I'll find once I strip paint off the exterior and take the vinyl top off. I'm just dealing with known rust for now ;)

SeanD
January 21st, 2010, 11:39 AM
Your car looked just like mine!

http://i42.photobucket.com/albums/e301/seanpaintsflames/CopyofDSCN2429.jpg

Mustangs Unlimited has those quarter patches. WCCC may have them as well. I just used a piece of flat metal and bent it into that contour over my sidewalk and kinda hammered it into place. It saved me a few bucks.

For the fender, I would just replace it all together. Patches over patches don't usually work out very well. Normally that rust spot is a lot smaller- mine was about 4"x4", and, again, flat steel bent into place and welded fixed it.