Where does water come from that rust out front floor pans?

[jeffsjag90]

 Where does the water come from that rusts out front drivers floor pan. Please no one say ski.

[Dino]

Windshield, cowl, firewall and any welded seam up there.  Water will find its way down and doesn't need a lot of space to get through.  Leaky heaterbox or heater control valve is also an issue of course.

Yank your seats and carpet out, get comfy and have someone hose the car down to find the leak(s), then you can start the fun task of finding its origin.

[hemi68charger]

And for trunks, it was typically condensation that formed under the rubber trunk mat that never evaporated. The moisture just stayed and hence, rotted the poor sheetmetal away....

[Dino]

And for trunks, it was typically condensation that formed under the rubber trunk mat that never evaporated. The moisture just stayed and hence, rotted the poor sheetmetal away....

Ironic isn't it, the mat was supposed to do good.

Perforated rear window channels don't help either.

[twodko]

You didn't say what you're driving. For 68-70 the windshield wiper grommets are usually the culprit........this is a direct water leak to the floor pans.

[Cooter]

All I have learned/reallized is you'll never stop it totally. They leaked when new, they were "Repaired" under factory warranty, then once the free stuff ran out, the floors were left to fend for themsleves. I have a buddy that refuses to believe he can't stop his '69 from leaking...5 years later and he's still pulling his hair out. I tried to tell him, the cars were a bad design when built, how you gonna redo that?

[hemi68charger]

All I have learned/reallized is you'll never stop it totally. They leaked when new, they were "Repaired" under factory warranty, then once the free stuff ran out, the floors were left to fend for themsleves. I have a buddy that refuses to believe he can't stop his '69 from leaking...5 years later and he's still pulling his hair out. I tried to tell him, the cars were a bad design when built, how you gonna redo that?

Clear Kitchen & Bath Caulk.... Everywhere................   

[jeffsjag90]

 !969 charger.My car is gutted is has a very small amount of rust in drivers floor pan that I am going to replace. So after I blast inside prime, paint I should just reseal everything and hope for the best?

[Mike DC]

   
Just to add  - the vinyl top trim mounting holes can allow water into the trunk compartment.  Same for the taillight gaskets. 

[UFO]

Snow,wet boots,all soaks into the carpet/jute padding.
Remember these cars used to be driven year round.

[Mike DC]

   
You'd think it would be possible to make a car seal up if you threw enough effort at it.  Epoxy primer & seam sealer would do a lot for the welded seams.

Modern cars have double seals on the doors and much deeper rain gutters in trunklid & front cowl areas.  But they aren't completely different items.  They are still just body shells made of sheetmetal with spot-welded flanges at the joints. 

Old cars do flex more at the unibody level than a modern ride which has to hurt the sealing.  But even then, old Mopars are known to be very stiff for the era.  And the OEMs have kept floppier car bodies sealed up since then.

[Cooter]

It seems we are not remembering that newer cars are built with computers. this means EVERY single panel is a direct fit, not some hack job the designer did in clay. All the body seam sealers used tend to last a million years. How many times have you been to a junkyard and seen the newer cars floors just sitting with water standing in them and not very much rust has formed? Well, that's because of the newer primer/sealers used on the bodies. Better materials, better craftsmanship, better sealers, all come up to a car lasting alot longer than a 1969 Charger..