View Full Version : TR6 Changing floorboards in a TR6

09-17-2006, 07:26 PM
I know that I have mentioned this subject before, that is, changing the floorboards in my TR6. Assume for a bit that I made the decision to change the floors (I have small rust holes and a general thinning of the floor because of retained moisture from left-in floor mats - my bad).
Questions: What is the best way to cut out the floors? Discs, saw, plasma torch, nibbler? Assuming that only one side at a time will be done, is it necessary to install a brace from A to B pilars? How much overlap is necessary from new to old metal and will a series of Clecos suffice to hold the new floor down before welding?

My thoughts are this can be down without a total repaint of the car, just pull everything out that will be ruined by welding flash and cover the rest. Am I dreaming?

I may well be pulling the engine for some work on the tranny, oil seal, clutch and ring gear and would this be a good time to do the floors? Would the lack of an engine cause any change in the torque of the body and cause the laying in of new floors less accurate?


09-17-2006, 07:51 PM
Bill, If you are not doing the outer rockers, then a brace will not be required. If you can get a spot weld drill it will save alot of trouble, just grind off what's left. but be sure and match up the new, so you won't cut out too much. AS for the clutch problem, why are you pulling the engine or do you just want to pretty everything up in the engine compartment. I can see you would have more room if the transmission was out. Be sure and paint the underside of the floorboard, I use zinc chromate and then paint over it, but on my last quart now, so I hope it's still around when or if I ever do it again. Wayne

09-18-2006, 07:03 AM
You shouldn't have any problems with body flex. When the bodies were originally built, they didn't have a load on them.

09-18-2006, 03:57 PM

Yes, I agree that a spot weld drill will be very useful. Also, in general use a cutting wheel to carefully remove much of the old floor. Most saws or cutting torches would very likely do damage to the frame underneath, and/or the fuel or brake lines. Speaking of which, you might already know to get under there and carefully locate all those lines before doing any cutting, i.e. where you'll need to be especially careful.

Yes, Clecos or pop rivets or even sheet metal screws can be used to temporarily hold the panel in place until you start tack or plug welding it in place. I think the overlap will be obvious, once you get the old tack welds separated. Just use the cutting wheel to "rough cut" the old floor out, leaving an inch or two extra at the perimeter. That remainder will be removed by drilling and grinding loose the factory tack welds.

I'm afraid I have to disagree a bit on a couple of the other points. Yes, the bodies were built separate from the frames originally (but each were undoubtedly built on carefully designed jigs). I bet many folks over the years have managed to install the floors without bracing the doors, perhaps with the engine and gearbox out of the car, too.

However, knowing that the combined body and frame of the IRS cars tends to flex a little. That's even more likely considering the car's age now, plus that the the body and frame have surely "settled" together a bit as a unit over the years.

So, if it were me, I'd prefer to have the car close to it's "normal" weight and sitting on its suspension while installing the new floors. I'd wait to pull the engine and gearbox after the floors are in.

You'll be removing the interior anyway, definitely including the dash-to-floor yoke or brace and likely also the steering column. By then, it would be relatively easy to go ahead and remove the rest of the dash and heater so they are completely out of your way (the wiring harness might be disconnected, marked and taped, zip tied or wired back, but not completely removed). The pedal assembly is relatively easily removed, too.

My point is, by the time the dash is removed, it's relatively easy to bolt in a brace from the windshield frame bracket/A-post to the hoodstick bracket mount at the B-post. So why not just add this extra measure of security? Sure, you could *probably* get away without bracing the top of the door. But why take a chance?

I just think it would really be the pits to weld in the nice new floor and *then* find something had shifted, that the the body had developed some sort of twist!

Welded-in door braces are often used effectively on full body-off-frame restorations, but I think bolted-in braces can work equally well when done right. I'd want to design any braces so they could be fitted before the door is removed and to allow the door to be easily test-fitted from time to time during the floor installation.

In my opinoin, it's better to be overly cautious than to have to do the whole job over again. Like so many projects, you might spend 75 or 85% of time and effort on preparation and only 15 to 25% on actually doing the repair!

Heck, I might even cross-brace to the opposite hoodstick bracket mounting holes and bring a another, vertical brace from that to the driveshaft tunnel/parcel shelf, too.

When it's finally time to install the floors, you probably know to go slow, tack weld the floor in just enough spots around the perimeter to keep it in place. Then refit the door to be sure nothing has moved. Only then go back and finish welding the floor a little at a time, not concentrating a lot of heat in any one area, to prevent warpage.

Incidentally, while you have so much of the interior stripped out is an excellent opportunity to make sure the lower steering column bracket is in good shape, correct any problems and perhaps even reinforce it if it appears fine. I don't know if this bracket was ever improved on the later cars, but it's very common for it to crack along the 90 degree bends on the earlier cars.

All that's really needed is a second plate of steel wrapping it and doubling up its strength. This can be welded in with relatively little fuss or damage to the existing paint on the firewall, if done carefully. It's a bugger to get to this bracket and repair it if it breaks later once the car is all back together. If that bracket ever breaks and needs to be repaired in the future, *a lot* has to be removed (which of you've already done for this floor project).

Yes, the top side of the floors can be pretty easily painted and touched up (don't forget seam sealer). Heck, it's all covered by interior trim and carpet, anyway, so doesn't even need to be "perfect". It will be a bit trickier to touch up the paint on the underside, which is probably even more important. But, it can be done.

There are various rubberized pads at all the body-to-frame bolted mounting points, that will need to be removed before welding in the floor. These are used to level the body on the frame and there can be varying amounts used in each location. I always try to remember to count the number of shims removed from each location. But, even then, if replacing some or all of them with new ones, the replacements can vary in thickness and it's common to need to do some fiddling to get it just right. The rubber shims on the outriggers, in particular, effect door gap front and rear.

One more thing that might be done at this time, if you wish, would be to drill a few holes and spray some sort of rust preventative inside the rockers. You'll have relatively easy access while the car is apart. There are already some drain holes that might be used on the inside below the floor level, just check that those aren't plugged up in any way. The most common place to drill additional holes is along the inner rocker above the floor level. These holes which are plugged with plastic caps after the rust preventative is sprayed in, and in turn covered by carpet trim eventually.

Keep us posted on your Winter project(s)!

09-18-2006, 05:21 PM
I will have to agree with Alan that it is in your best interest to brace between the A and B pillars. Since you are doing both sides, you might as well brace both sides right away. This will also allow you to put in a cross brace, which will really keep things from moving around.

The only point I will differ with Alan on is the necessity to weld in the braces. As you can see from the above attachment, I bolted in the door braces, and the year and a half that I've been working on the car, I have yet to see anything move. Also, with a proper brace, it shouldn't matter if you remove the trans and/or engine. Having that tranny out of there will make the job much easier. I lift the whole body off the car by the center brace with an engine hoist which is capable of rolling outside if I need to do work underneath or on the chassis.

As others have said, do one side at a time. Also, at one of the tech sessions for the club I belong to, I was in on a down and dirty method for putting in new floor pans. I didn't like the way it was done, but it was quick.

They cut the old floor out, leaving about an inch of material around the perimeter, with the exception of where the trans tunnel bolts on. Then the cut the same amount from the new floor pan...actually, they cut just a bit more, and then laid the new floor pan on the material that was left from the old floor, and welded the new section onto that. /ubbthreads/images/graemlins/eek.gif It worked, and the car is driving around now, but I opted to do a proper floor pan-ectomy on my TR3.

It's alot of work, but it's a satisfying job when it's done.

I liked it so much, that I went and replaced the trunk floor also. Now, on a TR3...that's a real project. /ubbthreads/images/graemlins/thumbsup.gif

09-19-2006, 10:08 AM
For those of you that have done this before, I need a little insight. How do you get a full floorboard in while the car is still on the frame? The attachment shows the car in its present state. I tried to get the floorboard in but it looks like I'm going to have to unbolt the body in the engine bay and atop the rear end. Do I need to unbolt or just cram it in? Also, when should I weld in the sill mounting brackets? I imagine that the sill brackets would go in after the floor is in, right?

09-19-2006, 03:37 PM
sure would be nice if there were a vacuum formed ABS plastic piece that could be epoxied in place.

09-19-2006, 04:29 PM
I haven't done this job on a TR6, but I have on my TR3, and there is some similarity. Because the floor actually lays on the frame in some places, I don't think that you can wiggle the floor in without lifting the body some. I had the body on my TR3 up a few inches from the frame when I slid it into position.

The sill mounting bracket problem I will let someone else answer, as I'm not familar with that. However, from looking at Moss online, it appears that they should go in first, as the floor lays on top. It might be easier to weld those on first, as you have better access then having to go underneath after the floor is in. Perhaps you can lay the floor in, use a few sheet metal screw to hold it in postion. Then you can position the sill plates, tack them in, remove the floor, and finish welding the brackets in.

09-19-2006, 07:35 PM
The best way to do it is to brace the car by tack-welding an X-bracing across the door openings (remove the doors), and then tack welding a square bar across the car into the upper-V of the X. Use a torch to cut out the large metal part of the floor, being careful not to touch the seams.
Pull the main piece of the pan, the center, out of the car. The pan's edges are kind of "sandwiched" in the rocker panel, around the firewall, and allong the metal bar that supports the tranny tunnel. Grind down the paint on the seams so you can see the spot welds, and drill them all out with a medium sized drill bit. Once you've got the spot welds drilled out, use some vice grips to pry the metal out of being "sandwiched" in the rocker panel and around the passenger compartment.

I hope this made sense. It's kind of hard to explain the process, and it's a fair amount of work, but you end up with a clean edge around the car and a nice, factory install once you've got it welded back in.