Floor Pan Replacement / Bracing

[z3beemer]

I've had several people tell me, and have seen it mentions in several other Floor Pan post, that it is recommend to installing  support bracing before starting the floor pan replacement, in order to keep everything in place and square during the process.  What I haven't been able to ascertain is where the bracing should go, and how to you install it so it doesn't interfere with the installation.  I plan to do one side at a time.  Help and recommendations are greatly appreciated (73 240Z).

[AZDatsun]

Generally speaking you put one end connected to the one side and the other end connected to the other side. Just don’t go front to back or back to front that’s not really important it seems.


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[grannyknot]

If the car is in poor shape structurally(rust bucket) then bracing is needed to maintain proper spacing but if the car is fairly sound and you only do one side of the floor at a time then you don't really need to brace, however you should leave the transmission mount/support in place to add some stiffness to the trans tunnel.

[z3beemer]

So if you install bracing, doing one side at a time, do you brace the side you're working on, or the side opposite the one you're working on?  Seems if you brace the side your working on it would be difficult to maneuver the pan around the bracing. 

[grannyknot]

Some pics would be very helpful,  how are the rockers, are they in good shape or rusted out?  If the rockers are good bracing isn't needed.  If the front seat support is good shape you can always just drill out the spot welds holding it to the floor pan but leave it attached to the trans tunnel and the inside rocker, that's lots of support.

[z3beemer]

Hi all.  I'm approaching the dreaded floor pan replacement on my 73 Z.  The good new is the trans tunnel and the rockers appear to be pretty solid so I should have something to weld to.  I may need to add some metal at the transition point up front near the firewall.  I have a few questions for those of you who have done this:

Is it better to have the car sitting on the wheels or propped up on jack stands?  If on jack stands, it there a particular spot to place the jack stands or just anywhere solid ( eg: suspension, differential, etc).

1. Which way is easier to install them: down from the top or up from the bottom?  If coming up from the bottom, is it possible to leave the front seat mount in place at the trans tunnel and rocker. I figure if this is possible it would act as bracing and eliminate cutting it out and re welding it back in.
2. For some reason my car does not have the frame rails that run under the floor pans from front to back.  My guess is that maybe someone removed them and tried to patch the holes (big holes) in the floor pans.  My floor pan kit includes the rails and I intend to install them. I know where they start at the front because a portion of the rail is still there.  What I don't know is where are they suppose to terminate at the back.  I'm thinking at the cross rail right behind the rear seat mounts???? (yes/no?)

Any help or comments would be greatly appreciated.

Z3beemer (Paul)

[grannyknot]

On 5/20/2019 at 6:40 AM, grannyknot said:

If the front seat support is good shape you can always just drill out the spot welds holding it to the floor pan but leave it attached to the trans tunnel and the inside rocker, that's lots of support.

That was my answer to #1?

#2, the rail ends where the rail ends, as long as the front of the rail starts a little forward of the seam the end takes care of its self.

 

[26th-Z]

Keep the transmission mount bracket in place to insure proper alignment at the tunnel.