Rusted Floorboard

1980-1986 Datsun 720 forums. All 720-specific topics and discussion can be found here.
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lalsimmons
Posts: 36
Joined: Tue Apr 03, 2012 6:06 pm
Car: 2009 Triumph Scrambler
1982 Datsun 720

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Hey everyone. I recently decided to change out my vinyl floor for carpet.

I pulled the seats and started pulling the flooring and stopped. The floorboard under the driver side is rusting. Not a pretty picture, like crumbly rusting. It seems ok in the extended cab, and I haven't looked at the passenger side yet.

Should I just carpet over the vinyl and don't disturb it?

Definitely rip it out, vaccuum and clean it and have someone deal with whatever is horribly wrong?

The truck is incredibly rust free, it is so super odd that barely a spot of rust and then the floor in this spot is super rusted out. Is this common?

I drive it occasionally in good weather, it is a hobby truck I have owned since new - I baby it, so it won't get worse i don't think. I just worry ignoring the problem may be a bad idea. Or maybe they all have problems like this and it is usually contained and I should just pay for it be patched.
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VStar650CL
Technical Expert
Posts: 8451
Joined: Thu Nov 12, 2020 1:25 pm
Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S

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lalsimmons wrote:
Wed Dec 15, 2021 6:19 pm
I baby it, so it won't get worse i don't think. I just worry ignoring the problem may be a bad idea. Or maybe they all have problems like this and it is usually contained and I should just pay for it be patched.
Rust never sleeps, except maybe in Death Valley. So your suspicions are right, ignoring it will be a bad idea. However, floorboard rust has always been common on trucks with unpadded vinyl in the cabin, simply because trapped moisture has no way out. Usually it will be limited to the sheet metal and won't affect anything structural. The most common solution is to hit it with rust neutralizer and then lay some new sheet metal under the carpet, but with a ride that's so pristine, I'd bite the bullet and do it right. Take a grinder to the whole rusted section, use body sealer to permanently lay down new metal, prime and paint, then eliminate the source with what you planned in the first place -- regular carpet, preferably padded.

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lalsimmons
Posts: 36
Joined: Tue Apr 03, 2012 6:06 pm
Car: 2009 Triumph Scrambler
1982 Datsun 720

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Thank you for taking the time. I will get the floor out and clean it up to see what I am dealing with. 98% chance a person who knows what they are doing will fix what I find. Do I go to an autobody, a mechanic, or is it strictly a restoration thing and I need to find a speclialist

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VStar650CL
Technical Expert
Posts: 8451
Joined: Thu Nov 12, 2020 1:25 pm
Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S

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Since it's under the carpet, it can definitely be a body-sealer job and not cutting and welding. So I'd think a good body shop would be the ticket.

Flynnstoned
Posts: 3
Joined: Fri Mar 25, 2022 6:15 am
Car: 1977 Datsun 620
1985 Nissan 720

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I feel that you should pull up/remove whatever is covering the floor, soak the floor in white vinegar for a day or two or three, remove the vinegar, see what you have left to work with (probably hit it with a wire brush too). Then (if you can't weld,) you could patch it up with fiberglass. Your cab likely leaks somewhere (just found out my back window doesn't seal at all,), and instead of evaporating the moisture is just eating the metal. And that's BAD.


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