Replacing floor boards and frame rails?

[New_BE]

Hello, my 240Z had some rust holes in the floor buti fixed em just by partching them up, for now. This winter or next spring, i want to put new floor boards in, and the rails that go under teh floor boards should in my mind be replaced aswell so i won't have to do it at a later date, i want my car to have many more enjoyable dayZ ahead....ok no more babbaling... Cuttin out the old board i understand, but this rail underneath i have had the car all jacked up and took a look at it i can kinda see where it is connected to the frame? (i'm not to sure if this is what it is) and it appears that it is welded in, so how do i go about romovien this? And do i need to remove anything other than the floor boards? can someone direct me in the proper direction thanks guys and gals

I also read in a post after i performed a seach that 2manyZs said u coudl do it without removing the floorboads but in this case the floorboards will be removed... thanks

[St.stephen]

Mr. Newbe,

Congrats on getting into the hobby! Honestly I would need to see some pictures to accurately give you some guidance on what you need to do however if we were going on the fact that your floors were a total loss you can do the following:

www.zparts.com (motorsport auto) has replacement floor kits available as well as a few others. I don't have the other links handy at the moment. The premium kit is a little over 300 bucks and the not premium kit is about 149. Depending on how bad your floors are, and what you want will determine what kit you get.

That support under the floor is not the frame rail. I repeat is not the frame rail. It merely is a support underneath the bottom of the floor. If you look it stops about 3/4 of the way down the floor. This support only ties into the frame rail cradle and you can see where it ties into by removing the sound deadening material on the drivers toe board and looking jsut left of the gas and brake pedals. you will two rows of spot welds holding the toe board to the frame rail cradle. If your car need frame rails (in the engine compartment, you will know)

Honestly if you are getting into this project time to do it the right way. If the floors are a total then cut out all rotted metal. It's going to be a scary sight. when the cutting stops. I prefer to use an air driven cutter, similar to a large dremel if you will. A cutting torch works well, however rusted metal does not cut clean. It curls and throws sparks.

My current car has the driver and passenger sides cut out from the toe boards to the seat mounts. If you can manage it, try not to remove the seat mounts. Not only is it a little difficult to get the mounts in correctly to the new floors, it gives you something more to weld the floors too. I suggest mig welding as it is easiest and produces great results for the guage metal you working with.

Once your rotted metal has been removed and all edges smoothed, it;s time to fit the floor it. It's important to remove all the rust as you need solid metal to weld to. The kit will have the floor support already spot welded to the bottom. I cut notches in my floor where the support is so it will fit over what was left of the support coming from the frame rail cradle. I had to reconstruct the toe board on the driver side and then fit the floor. From there it's bend and shape until they fit snugly and then weld them in. My kit took has taken some work to get it in, however all of them have. They say that the floors do not have to be welded solidly, a half inch bead every inch is enough. You make the call. If welding it solidly is overkill than call me overkill. I want no water ever rusting my car again.

Upon getting all the welding done now it;s time to seal all the seams with something like 3M body sealer. This is very important and you need to do it inside and underneath. Once that is dry I would treat the new floors inside and underneath with POR-15 www.por15.com and then paint with a topcoat. reapply your sound deadening material and conitue to drive your new rust free floor Z!

I'm sure you have many many more questions and I just breezed threw that so feel free to drop me an email if you have any further questions

[mperdue]

his floor kits look the same as the ones from MSA - only a lot cheaper.

http://web.ctsolutions.com/zeddfind/

[EScanlon]

I've seen several posts regarding Charlie Osborne's Floor Pan Kit and everyone who has used them has been extremely pleased not only with the gage of metal but also with it's ease of installation (dimensions are right on target) as well as the fact that it duplicates the "original" floor pan design.

Z Findings

Charlie Osborne

603 Compass Court

Kingston, Ontario K7M 8V9

Canada

Tel: (613) 389-1397

www.datsunzparts.com

www.datsunzparts.ca

E-Mail: zeddfind@kos.net

[m240]

My 240 also has the dreaded floor board and frame rail rust disease. I'm thinking about weliding in some patches or even new floor boards. My car came with a set of the less expensive MSA floor boards. My question is, is there enough room under the car to weld them in if it is on jackstands or does it have to be on a lift? I've never welded before but I figure with a little practice I should be able to do it. Will the less expensive MSA floor board kit comprimise the rigidity of the frame?

Thanks,

Mark

[St.stephen]

M240....theoretically you can weld these items in while the car is on jackstands, Honestly I wouldn't recomend it..... however I would have the car as high as you can safely get it. I have never welded floors on a car that wasn't completely disassembled. I would be sure to remove anything that could catch fire. carpet, fuel lines, wiring, etc. Be sure to cut out ALL the rotted metal so you have some solid metal to weld the patches to.

Honestly most of the kits are the same design so the one you have wil work. Just remember that these are not direct "weld in" replacements and will require some fiddling and fitting to get them to work but you can achieve good results. As far as structural rigidty, just be sure to have good solid welds and you should be fine. I have been told that a half inch bead every inch or so is fine and welding them in solidly is overkill. Call me overkill. I like to make sure they are strong and in there.

Be sure when you are all done welding you seal all the seams inside and underneath the car and coat with a good resut preventitive such as POR-15 to ensure you only have to do this repair once.

[m240]

Hmmm, So this doesn't sound like the kind of job to do in the driveway. Maybe I should take it somewhere to have this done. I just hate to pay someone to do something that I think I could do myself. Thanks for the advice.

[Guycali]

OK. I finally had time to jack up the car on all four wheels to inspect the underbelly. The driver's floor has no rust but is caved inward in certain places. The guy who sold me the car said he had rust underneath driver's door repaired at one time. I hope what I'm seeing is not a sandwiched repair work. The passenger side has a crack across the floor width-wise.

Should I replace the entire passenger floor or just repair the crack? The frame rails before the firewall (jacking points) seem to have caved inward a bit as well. Should I replace the rails or leave them as they are? Thanks for the help.

Argh! Rust!

-Wilbur

[2ManyZs]

Guycali, after looking at your pics I would say you are in pretty good shape. The cave-ins were probably caused by someone who didn't know how to jack up a Z properly or maybe putting it up on a lift with their eyes shut.

If the rails are solid, no weak areas that you can find, I wouldn't worry about them. The only area you need to work on will be the seam across the front on the passengers side. The seam where the floor pan welds to the firewall is what is rusting out. You will probably need to get rid of all the loose rust flakes, and see how far the rust has progressed. If you can keep it in a small area, maybe a couple inches wide, I would suggest POR-15 on what is there and a small patch panel on one or possiby both sides.

You could probably use a block of wood and hammer out the caved-in section of the floor pan on the drivers side form inside the car.

All in all, it looks pretty good. Not perfect but far from what others have seen.:cross-eye

If the floor pans have no rust on the inside I would just repair the one rusted out area and POR-15 them good inside and out.