Technical Assessing rust - floor panels

[smahaley]

Good evening all -
Today on the project (1978 Spider restoration / resurrection) I uncovered the floors and removed the seats. My simple, naive question is: How do I accurately assess the rust damage so I know where I am going to need to replace metal?

Following are some lovely shots for your info and interest:

Passenger side

Drivers side


Looks like some fiberglass was applied at some point. The rusty cracks extend to the back - I have not yet removed the carpet.

Thanks in advance!

 

[Slotman]

Offered only as an in general suggestion first all the fiberglass needs to be removed, clean up the entire area to better access what your dealing with, I'm not sure if replacement panels are available? If not, or if there are just small areas that need metal replacement you might consider getting an affordable mig welder if you don't have one, find an old body panel the same guage for practice and patch panels and go for it, rust preventive products can be used on the rest, and one product I like to use, some like it, some don't is POR 15, as a final top coat...I recently did the floor in my 55 chevy and it added strength to the floor...

 

[smahaley]

Offered only as an in general suggestion first all the fiberglass needs to be removed, clean up the entire area to better access what your dealing with, I'm not sure if replacement panels are available? If not, or if there are just small areas that need metal replacement you might consider getting an affordable mig welder if you don't have one, find an old body panel the same guage for practice and patch panels and go for it, rust preventive products can be used on the rest, and one product I like to use, some like it, some don't is POR 15, as a final top coat...I recently did the floor in my 55 chevy and it added strength to the floor...

Thanks, Slotman - I will look into POR 15; and I don't yet know where the fiberglass ends and good metal starts... I have found replacement panels online, but am worried at the moment that the rust damage creeps beyond those boundaries. I'll just have to do some more cleaning and poking around. Also, my neighbor has a MIG welder he's going to give me (!) so I'm doing some reading and watching on what that's all about....

 

[Slotman]

Heck yes! Grab that welder, find an old door or fender from any car with close to the same guage of metal and practice! You will be surprised what you can do! I learned to weld in junior high where my teacher started me with oxy/ acetylene welding, I was not given any rod until I could flow a puddle melting 2 parts together first..mig Is easy...and again look in to the POR 15, it's always worked well for me...I'm curious, have you seen replacement floor pan panels? Terry

 

[Slotman]

The Eastwood company sells a lot of usefull items for the path you are going down repairing your floor...

 

[124BC1]

The worst corrosion on floor panels I've seen were at the outer edges where they join the inner rocker panels (currently hidden under the remaining carpet sections) and at the forward section under your heels - there's a frame crossmember (support panel) underneath this area of the floor that gets blasted by road grit from the front tires, can trap mud/dirt and then rusts away, also rusting the floor in the process.

Additionally, iirc, the rocker panels on these cars don't have just an inner and outer panel, they also have an middle sill panel which also rusts, so replacing the rockers involves obtaining or fabricating 3 panels each side and then trying to make them all fit correctly while ensuring that the bodyshell is correctly supported/braced to avoid misalignment/sagging.

When assessing the car, don't forget to pay particular attention to areas that can compromise safety e.g. suspension pick-up points, some of these can be extremely difficult to repair in a home workshop e.g. I've seen serious corrosion on the front suspension shock towers, cracked front frame rails where the front suspension crossmember is attached and rusted out rear frame rails where the rear axle trailing arms/links are attached. Hopefully your car doesn't have any of these issues.

Outer body panel repair is feasible at home and usually not safety critical, but beware that corrosion on an outer body panel is often accompanied by more serious corrosion on the structure underneath or the outer panel mounting flanges.

 

[124BC1]

----------------------.I'm curious, have you seen replacement floor pan panels? Terry

Replacement floor panels are listed on the autoricambi.us website, >124 Spider1966-85 > Exterior > Body Panels , they're on page 2 and 3; front section floor panels are $160 for each side and rear section floor panels are $130 each side - there's also a few extra small panels needed for e.g. seat supports.
(there may be other suppliers of these panels, this was the 1st w/site I tried)

 

[smahaley]

The Eastwood company sells a lot of usefull items for the path you are going down repairing your floor...

Thanks a ton - and here’s one of the links on floor panels : https://www.c2cfabrication.com/products/1968-85-fiat-124-front-floor-pan-lh

 

[smahaley]

The worst corrosion on floor panels I've seen were at the outer edges where they join the inner rocker panels (currently hidden under the remaining carpet sections) and at the forward section under your heels - there's a frame crossmember (support panel) underneath this area of the floor that gets blasted by road grit from the front tires, can trap mud/dirt and then rusts away, also rusting the floor in the process.

Additionally, iirc, the rocker panels on these cars don't have just an inner and outer panel, they also have an middle sill panel which also rusts, so replacing the rockers involves obtaining or fabricating 3 panels each side and then trying to make them all fit correctly while ensuring that the bodyshell is correctly supported/braced to avoid misalignment/sagging.

When assessing the car, don't forget to pay particular attention to areas that can compromise safety e.g. suspension pick-up points, some of these can be extremely difficult to repair in a home workshop e.g. I've seen serious corrosion on the front suspension shock towers, cracked front frame rails where the front suspension crossmember is attached and rusted out rear frame rails where the rear axle trailing arms/links are attached. Hopefully your car doesn't have any of these issues.

Outer body panel repair is feasible at home and usually not safety critical, but beware that corrosion on an outer body panel is often accompanied by more serious corrosion on the structure underneath or the outer panel mounting flanges.

Whew. Thanks a ton for this; I’m going to remove the top today along with back seat and carpet and start to suss it out. I think previous owner spray coated the bottom of the car (oh boy) with Line-X or something. I’ll check at the noted areas. More progress photos soon.

 

[Slotman]

Looking forward to seeing photos with everything out....I'm curious, does the coating applied to the underside of your car also appear under the hood in the engine compartment? My 79 has what appears to be spray undercoat in the engine compartment and front suspension as well as under the car that I've always hated...I've always wondered if it was factory applied in mine...it's never fun scraping off stickey goo before you start a job..I hate the stuff, people think how easy it is to spray on, and how clean it looks, but it just causes problems later if you have to work on that area...the stuff is even flammable, the por15 I spoke of drys hard as a rock...

 

[Slotman]

P.s. there's a pair of vintage rockers on ebay that look to be just the outer parts, not sure if the price is reasonable or not, just an f.y.i.

 

[The Panda Nut]

No substitute for getting stuck in and lightly grinding away the rust with a flapper disc back to good metal. With vintage cars we are not talking primary safety, just stopping your feet touching the ground, and structural strength in places. If you are keeping the car long term a new floor would seem a great investment if its neatly and properly installed. I love the car, Good luck with your project.

 

[smahaley]

Got the top off today and the back seat out. Doesn’t look too bad - having a bit of a time working out the roll bar bolts though.

Before I take the dash out I decided to run 12v in the system (battery and external charger) to see what works. It’s a hodgepodge - some lights, not all of them. So I am sure I’ll be reworking the wiring as part of this …

 

[smahaley]

Looking forward to seeing photos with everything out....I'm curious, does the coating applied to the underside of your car also appear under the hood in the engine compartment? My 79 has what appears to be spray undercoat in the engine compartment and front suspension as well as under the car that I've always hated...I've always wondered if it was factory applied in mine...it's never fun scraping off stickey goo before you start a job..I hate the stuff, people think how easy it is to spray on, and how clean it looks, but it just causes problems later if you have to work on that area...the stuff is even flammable, the por15 I spoke of drys hard as a rock...

Good to know, Slotman. No, the underside seems to have the black spray-coating in *some* of the areas. Under the hood, it's all normal, as well as in the trunk. The floor boards do seem to have a coating on the interior - I think it's fiberglass. I agree - the coatings seem to have hidden active rust. I'm going back into it shortly...

 

[Slotman]

I've removed fiberglass from metal auto body a couple of times, and worked with it in the aerospace industry and it usually delaminates itself from metal pretty easy so hopefully it will peel "right off"

 

[smahaley]

I've removed fiberglass from metal auto body a couple of times, and worked with it in the aerospace industry and it usually delaminates itself from metal pretty easy so hopefully it will peel "right off"

Well - I took the passenger door off and related trim, pulled carpet bits and sub padding and here’s what we’ve got. And you were right Slotman, the layer of what I guess is fiberglass. Removing that revealed holes. I guess my question now is whether the floor panels I can buy will cover everything that had to go. The rockers look good as well as the center tunnel.

 

[Slotman]

I'm looking with a semi old set of eyes on my phone, but yes it looks like your ready for at least one floor pan...if dimension wise you need a bit bigger than the replacement panel then that's where making your own piece to close up the gap from an old body panel might come in handy...looks totally do-able! And it's a bonus if you don't have to mess with the rockers! Looks like you know what your doing, are on the right track and are doing a great job!

 

[smahaley]

Back at it today: I’m clear that front and rear floor pans need to be replaced. I think I can salvage the seat supports (will need to do a little patching).

The tear-down continues; first look at the rear brakes - looks like someone put new calipers on. Also looks like an elec fuel pump retrofit?? Also am curious if you fine folk think I should replace the fuel tank. It has been sitting for a couple of years.

 

[Slotman]

With your tank you may have options...I have a color endoscope you can buy cheap on the Chinese websites that delivers a color picture with a light on the end of the camera, mine has its own screen, there are more inexpensive models also that use your phone, look inside, there are tons of videos on YouTube where people load a bunch of stuff inside the tank to scrape it, then wrap it in a comforter and let it go in the dryer for a time, then you can use a kit to recoat the inside if you choose or not,
Or if it looks pretty bad inside you can do what I did with my lowrider 68 mercury wagon, wagon tanks are impossible to find so I washed my tank out with dawn, an internet suggestion that completely removed all traces of gas smell, and shipped it to a place with excellant reviews called Moyer gas tank renew or something like that, and they redo both the inside and outside of your tank with photos if you ask, then ship it back to you..I'm betting that would be cheaper than the $800 replacement on ebay...buying another used one might be a crap shoot...just a few ideas for ya...
Terry

 

[Slotman]

Wanted to add, it may or may not fit in a dryer, that method works best on motorcycle tanks, but anything to shake it up and agitate it with something Inside to scrape around...I've heard not to use Chain as it can get stuck inside...check out YouTube for ideas...