Does my floor really require fixing?

[BlazingBullet]

Just got my first Z and I'm wondering if you guys can instill your wisdom. 

Is it worth tearing back the sound deatening and look for rust under my floor? Most rust looks to be surface so surely i can just rust kill it, clean it and then spray rust inhibitor and call it a day? I don't really want to make more work for myself if I don't really need to. 

[GregTas]

Unless I missed something it looks like new. Just a bit of rust converter on those spots and a bit of paint over it and your're sorted. You're a lucky man.

Important bit is underneath. Make sure underneath it is well sealed along the length of the chassis rail between rail and floor. They were just spot welded together and so water can get in here between rail and floor and rust out from inside the rail.

Edited December 28, 2019 by GregTas

[gav240z]

Hmm moisture gets trapped under the sound deadener and may cause rust. Depends on what your doing, but if doing full body resto I'd pull it up. But if not. For now use converted and seal with something like KBS rust seal.

Ripping it up is a pain, but you may find holes in the floor under it. Depends on what you can see on the other side.

But if your still using it regularly and it's not a resto project. Don't open a can of worms (yet).

[BlazingBullet]

3 hours ago, gav240z said:

Hmm moisture gets trapped under the sound deadener and may cause rust. Depends on what your doing, but if doing full body resto I'd pull it up. But if not. For now use converted and seal with something like KBS rust seal.

Ripping it up is a pain, but you may find holes in the floor under it. Depends on what you can see on the other side.

But if your still using it regularly and it's not a resto project. Don't open a can of worms (yet).

Yeah, I've already noticed this effect in the spare wheel well. From what I can see, the water gets underneath the sound deadner because there deadner isn't worked into the embosses?

If the deadner is firmly pressed against metal, that particular area shouldn't have any rust right?

Also, how rust-prone is that cavity in the box section where front seat's are bolted on?

Thanks for the replies so far guys - very helpful.

Edited December 28, 2019 by BlazingBullet

[C.A.R.]

After 40 years, the sound deadener has lost it's adhesion & started to lift letting moisture in to sit and rust the floor.
I haven't found one Z yet that didn't have some form of corrosion starting.

I suggest you remove all the sound deadener, wire bush the effected areas and apply a coat of rust converter.
Once dry, prep & repaint the area. 
After which you can reapply some new sound deadener like dynomat or carbuilders.

I suppose if you were feeling lazy, you could poor rust converter onto the floor and let it work it way in under the deadener over 24hrs...

[gilltech]

+1 to the feedback given to you above. The sound deadener pad is a bitumastic matrix type of product which after 40+ years has simply dried out; as bitumastic products whether used on vehicles or buildings in all their various forms must surely do, none of that stuff can last forever. Time to replace it at a time to suit you.

Any of the cavities and hollow sections making up the body shell are liable to attract crud and moisture and will rust. The automotive industry didn't pay much attention to rust prevention way back when our Zeds were built (no dipping back then). Some areas of the Z shell were lucky to even get a single thin coat of primer, and hidden areas where paint mist couldn't reach got nothing at all. So the more you can do to preserve the shell the better.

Edited December 28, 2019 by gilltech

[gilltech]

Further to my above, IMO Nissan painted the absolute minimum on our Zeds, well on my early unrestored 260 it was the case anyway. Remove the guards and scuttle panel, and the interior trim panels, and there's only the cream coloured primer (with a minimum of red overspray) to be seen. So not much paint protection from new. IMO those who restore these cars do a far more thorough job of it.