The plate on the underside of the footwell, does it serve any purpose other than attract rust?
​Is it ok to remove it and if so how do you do it?
I read somewhere that it was used in the manufacture of the car and serves no purpose.

 

It's purpose is solely to cause corrosion!
You should be able to remove it from underneath with a grinder and get back to just the floorpan. This was my intention with my XK8, but the floors were already a disaster and I had to cut them out and reweld.

 

Gents,
Any chance of a pic to show the location where this PITA extra floor plate is located?

 

Picture of the plate as requested.

 

It appears as if that plate is part of a reinforcing bridge that connects the front frame extensions to a more outboard section of the cowl/firewall. this obviously provides side to side movement stability and most probably torque control of the front frame extensions. by connecting the floor pan it also keeps the car from sagging. the floors become a tensile support in the way road sections are held together in a cable-stayed bridge. in any of these cars but especially a convertible this should be in place and complete in good order.

this is the result of the old XJS platform being repurposed. the forward frame extensions were definitely completely redesigned. if you remove the wheel well liner, the 45 degree plate between the forward extension and firewall bulkhead becomes apparent. it is also obvious that it turns 90 degrees to travel along the underside of the floor pan. by extending in this manner the welds along its length spread out the load over a greater distance along the floor pan much like a stitched fabric uses many individually weak threads to achieve greater strength along its seams.

the nice thing is that the area between the plate and floor is open at the 45 degree section in the wheel well and there are some underside drain holes. this situation makes rustproofing very easy if one is not against making one great big mess.

a hot rod builder looking over the underside of my car verified this when he said that our cars looked like custom builds where something was well modified from another vehicle.

it is the history of the car as well as a very necessary structural member. it must be present and if repaired done properly which probably means replacing the complete plate from the wheel well area around to the floor pan.

i recommend the corrosionfree product for preventative maintenance. you will have a mess when you do it, but it does not make you feel like you ruined the car. and i advise doing this job yourself as the applicators might not know this car or being willing to dismantle to work on this area.

 

According to the original owner my '97 has always been garaged and never driven on salted roads. Going by the condition of the undercarriage I'd say that's the best rustproofing of all! That area certainly looks like it would retain corrosive chemicals and moisture.

 

I disagree about it being an important structural part. It literally sits under the floor, not connecting anything to anything else. Like many repaired cars, mine doesn't have it.

 

take out the wheel well liner and look at where the front of that plate goes. it is part of the 45 degree brace between the forward frame extensions and the firewall bulkhead. designers do not install parts without reason.

 

 

yes

 

If it was part of a brace it wouldn't have a step in it, which would allow flex in the direction you suggest. The actual car floor has a ridged profile to provide rigidity, whereas that plate has no bracing or profile to allow it to contribute to the rifidity of the car.

I don't think anyone said it was there for no reason, but that reason is widely acknowledged as being part of the production process, not part of the rigidity of the car long-term.

 

see your point. the next time that i am under the car will give it a fresh look. it is similar to the torque boxes installed on classic mustangs in the 60s.

sorry that you had to deal with the rust, never fun. although recreating panels is rather satisfying work.