replace entire floor, or just sections?

[paradigm]

Pulled up the carpet on my 87 GN and as I suspected, the floor is rotted through in areas. The worst area is the driver front footwell area. The driver rear footwell has some smaller holes in the corner. The passenger front doesnt look too good, and the passeneger rear footwell also has some holes in the corners.

The center tunnel looks good, and the rocker panels along the side look solid.

How would you approach this? Replace the entire floor? Or replace the entire left side and right side? Or try to salvage the existing floor with wire wheel / rust jelly and patch where needed?

 

[pagrunt]

Find the extent of the rot to see how big the floor sections are damaged & repair/replace as needed.

 

[86LK]

use a phillips head screwdriver and see if you punch new holes by putting pressure on multiple spots. if you can push-thru, replace entire pan. I'd say replace front driver pan and passenger rear pan regardless. those rust holes are from standing water so the entire area has thinned out.
wirewheel front passenger and inspect; if it's questionable, replace the pan

 

[Bonnewagon]

Did you find the leak that caused this? I would cut out the really bad parts and fill with welded in sheet metal. . The surface rust if it does not go through I would wire brush and either POR-15 or fiberglass. I POR-15 my entire floorboards just in case a leak like this occurs. That has saved me more times than I care to admit.

 

[jcelk]

more than likely the metal is paper thin or rusted through all over check with a hammer or screwdriver . i would seriously consider replacing the whole thing it would be a much nicer job and would look perfect from underneath you will need to pull the trans

 

[Sweet_Johnny]

It looks like the driver front and passenger rear pans are the worst. Maybe replace those two and spot patch the other areas.

 

[paradigm]

use a phillips head screwdriver and see if you punch new holes by putting pressure on multiple spots. if you can push-thru, replace entire pan. I'd say replace front driver pan and passenger rear pan regardless. those rust holes are from standing water so the entire area has thinned out.
wirewheel front passenger and inspect; if it's questionable, replace the pan

I was able to take the phillips head screw driver and punch through driver front and passenger rear pans and some of the passenger front. Driver rear seems solid enough. Center tunnel of pan seems OK but there is one spot above the passenger seat belt receptor threaded hole that seems soft.

I am able to barely find enough metal it seems to weld to along the perimeters to replace the entire front and rear passenger side, and the driver front piece. Or I can go through the larger job of removing the transmission, engine and replacing the entire pan. LS engine and transmission are just sitting in the car, not fully hooked up, and there is no drive shaft. Not sure if I should try and get the motor fired up to see if it runs and then pull it to paint it and maybe do cams / springs.

 

[paradigm]

Did you find the leak that caused this? I would cut out the really bad parts and fill with welded in sheet metal. . The surface rust if it does not go through I would wire brush and either POR-15 or fiberglass. I POR-15 my entire floorboards just in case a leak like this occurs. That has saved me more times than I care to admit.

I am unsure where the source of the leak is. I just got the car, and its sitting in my garage now. It sat outside for a few weeks with heavy rain, and when I would go into it after it seemed dry inside. I also washed it and it seemed dry inside, but clearly water was getting into it and sitting in it. Or the car was sitting somewhere like a wet grassy area for a long time, not sure of its prior life but it looks to have been sitting outside for years.

 

[paradigm]

more than likely the metal is paper thin or rusted through all over check with a hammer or screwdriver . i would seriously consider replacing the whole thing it would be a much nicer job and would look perfect from underneath you will need to pull the trans

I took a crew driver and punched through driver front and passenger rear pans and some of the passenger front. driver rear and most of the tunnel, and rockers are solid. Rust is creeping up the sides of the tunnel and there is a soft spot near the passenger seat belt hole. Not sure how the rust is under the center brace area.

I agree replacing the entire pan is the best thing to do, however it will be a lot of work and I may need to get a shop to do it which requires removing the drivetrain and getting the car to the shop and hoping the shop doesn't screw me over by letting it sit, letting it get stolen (I am in Long Island right outside of NYC), etc. Or remove the drivetrain and try and replace the pan myself. The entire pan looks like the only way it can go into the car is from underneath, which requires taking out the trans, and maybe the motor for the firewall area?

 

[paradigm]

It looks like the driver front and passenger rear pans are the worst. Maybe replace those two and spot patch the other areas.

Yes the driver front and passenger rear are the worst, but I would also look to replace the driver front too. So basically the entire passenger side of the pan and the driver front.