Not a happy discovery- rusted floor pan

[Mike Self]

4 hours ago, VWScott said:

There is evidence that heater core was leaking at some point. It must have been repaired because it is not currently so damage has been done.

Yours seems to be a '76; if so they are notorious for front footwell rust, even when they were only 4-5 years old if driven in salt country.  The apparent cause is the factory using a different (or faulty) sealer to hold the round removable floor drain panels in the floors (which allowed the body to drain when it was dipped in primer during assembly).  The sealer used on the '76s dried out and allowed water to intrude into the footwells, under the tar and sound deadening--made further inaccessible by the squarelight's one piece carpets.  You didn't notice a problem until your foot went through the floor.  

 

Doesn't help with your floor replacement, but at least you know the probable cause, and aren't alone among '76 owners...  Oddly enough the floors in my '69 were one of the few places I didn't have to repair, after 30 Ohio winters they were nice and sound.  It was just everywhere else!

 

cheers

mike

Edited January 19 by Mike Self

[popovm]

A wire cup on a drill is about to become your best friend. Since it sounds like you’ve done rust repair before you already know that you gotta find the edges of the rust. 
 

I am one of those tragic ‘76 owners and am currently wrestling with a floor pan to get it to fit my driver’s side (see thread linked previously)
 

Couple notes:

The frame rail piece that goes under the floor pan is made of a lot thicker than metal than the floorpan. After I drilled out the spot welds to expose the rail I found that my rail was thankfully solid. 
 

The firewall that attaches to the front top of the floor pan is thankfully mostly flat sheet metal. I was able fairly easily fab a couple pieces using some 22 gauge sheet metal. (I did some trimming after this so it’s not a perfect reference photo)
 

Before:

 

The rear part of the inner fender needed a patch too. I just finished this piece tonight (pic below). The upper flange on this piece supports the back of the larger patch panel from the previous photo. 
 

 

It’s all a lot of work but I am enjoying a lot of it. Let me know if you need anymore pics. There are also a lot of great photos on this site of this job from @D.martijn, @Dudeland, and that other floorpan thread linked earlier. 

[NMDerek]

I blame BMW, they have the right press molds, they could of rocked the world and come out with a stanless steel modernized (fixed the rust spots), same lines, 2002 , in 2002

when I win the lottery I will , just to show them I got game 😎

Edited January 19 by NMDerek

[TobyB]

Quote

they have the right press molds,

The last of those were scrapped in 1994.  And turned into E36es.

 

Which were then scrapped and turned into the dies for the E60.

 

Which were then scrapped and turned into Fsomethings and the world ended.

 

And no matter, the dies that press high carbon steel aren't right for stainless anyways.

 

t

would like the world to be more simple, but it ain't.

[tech71]

12 hours ago, TobyB said:

The 2002 has no frame rails-

Say what? Guess I’ve been ordering the wrong parts all these years.

Thanks, next time I will know to order 

“the trailing end of

the bottoms of the front fender structure” R/H or L/H of course.

Nomenclature…….

Edited January 19 by tech71

[Mike Self]

Another cause for rust in the front floor area is a leaking master cylinder, brake fluid reservoir, or the hoses that connect the two.  Leaking brake fluid will run down the driver's side frame rail to its bitter end under the driver's side floorboard--and proceed to first rust the frame rail, the spread to the floor where the two are attached.  Worst part is like those loose floor drain plugs on 76s, you don't notice it until you crawl under the car for something else.  And that problem isn't confined to just 76s, all year cars can do that.

 

cheers

mike

[VWScott]

It is evident upon further investigation that the leaking originated in the AC system.The rust followed gravity directly from where the two AC lines entered the cabin which is more to the passenger side.The worst rust IS ther passenger pan where the whole front as well as partial foot resting panel is rusty. I mean under normal rust wear its the driver side that gets the most ,wet feet etc..  and my car reflects just the opposite where the driver is rusty yes but not to the same extent as the passenger side.The coup de gras however is the total botch job for the "fix" on the driver side. I must say I thought this sort of hackery was limited to the broke ass VW world.Apparently not. Pics forthcoming. To the best of my knowledge the chain of history of the car was: Cali,Nevada,Kentucky and now Indiana. According previous owner AC was out by the time it landed in the Bluegrass State.I'm sure the AC saw plenty of action in Cali and Nevada though.

I've never been a fan of AC in vintage cars though that may be tempered by the fact I live in Indy and I'm used to schlepping around in old air cooled VWs though my Honda has it and I never use it.

[popovm]

I don’t have a great pic of it but the bodge on my drivers side included my gas pedal. Lol. That whole green piece of metal was attached to the original pan using sheet metal screws. In other words, you’re in good (?) company. 😄 
 

[VWScott]

lol,it gets worse! I will update with pics

[TobyB]

shit, sorry- but better to know now than AFTER you fixed the floors...

 

t

 

[Mike Self]

23 hours ago, VWScott said:

It is evident upon further investigation that the leaking originated in the AC system.The rust followed gravity directly from where the two AC lines entered the cabin which is more to the passenger side.

And a little more hard-learned rust lesson:  I'll wager that one of those previous owners who used their A/C a lot didn't notice the condensate pan drain hose--that should have allowed all the condensed water from the A/C evaporator coils to drain out under the car--had plugged up, allowing all that water (and there's a lot!) to overflow its drain pan, run down under the carpet onto the spongy foam padding and rust your floor.  When that pan overflows, it's generally to the passenger side footwell...Old Datsun and Nissan pickup trucks are notorious for this, and their pans can hold over a pint of water!

 

mike

[chargin]

On 1/18/2024 at 5:08 PM, tech71 said:

our 76 was built with a fuel return line routed along the rocker panels, think brake lines are located running thru the tunnel.

on a 76 brake line on the rail area also, drilled a hole in one on accident 😖

[Son of Marty]

The rust could also be from a leaking heater box to body gasket.

[ray_]

9 hours ago, Son of Marty said:

The rust could also be from a leaking heater box to body gasket.

This!

 

Cheers,

[BeMyWay]

 

VWScott, 

 

How's it going?  Do you have any updates for us...me?

 

I want to perform floor pan surgery on a '75 (which previously had ac) and I am always interested in learning about how you decided to attack.

 

Take care.