Advice on rust repair please

GNRick

Retired member
Joined
Mar 21, 2004
I pulled up the carpet and found three holes in the passenger floor board behind driver's seat. The body shop owner thinks he can patch it but he wants to look at it again. I think it would be better to cut out all the rust and weld in a new rear floor board. The piece is only $50 on Ebay. Is this a big job? They make it look easy on tv. The rest of the floor just has some surface rust. What do you guys suggest for treating/repairing the floor, front and back? Thanks.
 

Attachments

  • 87 gn rust Nov. 22 2010 001.jpg
    87 gn rust Nov. 22 2010 001.jpg
    97.3 KB · Views: 444
  • 87 gn rust Nov. 22 2010 002.jpg
    87 gn rust Nov. 22 2010 002.jpg
    91.1 KB · Views: 426
  • 87 gn rust Nov. 22 2010 003.jpg
    87 gn rust Nov. 22 2010 003.jpg
    84.1 KB · Views: 410
  • 87 gn rust Nov. 22 2010 004.jpg
    87 gn rust Nov. 22 2010 004.jpg
    79.8 KB · Views: 438
Except for that first pic, much of that could just be surface rust. I'd take the pic end of a body hammer and tap around (not too hard) to check the integrity of the metal. Anything that seems solid can be wire brushed to get rid of loose scale and treated with POR 15.

The holes in the first pic need to be replaced with metal. Here on the west coast, solid floors in G bodies are a dime a dozen. If you find a patch from a donor car, I think that may be the better way to go since the OEM metal is thicker the repoduction and usually fits better than repop. A fix like that would be pretty easy if you can weld a little and have an angle grinder.
 
i agree 100% buy a piece of floor out of another car. if your car is a ttop water may of leaked in from the roof and that may need fixing too.
 
If you haven't done so, I'd also check under your headliner since that's a common problem area. Doesn't look like too much of a job to fix though.

Peter
 
Car has a sunroof, no t-tops. I removed the 1/4 glass on both sides and couldn't see any traces of water getting in. Any chance this is normal rust for a midwest car that sat outside most of its life?
 
That looks like it rusted from the inside out. Previous owner(s) might have left the astroroof /window open in a rain storm and it got soaked, The Original GM carpet is nice and heavy duty but the rubber underside of it makes it very hospitable for rust formation since its hard to dry stuff out after a soaking.
Thats my theory.
I had a astroroof car where I had to do the same.
 
After looking at pick I would check the drain lines on the astro-roof and check and repair windshield seal. I find most time its the windshield and the seam sealer below left and right side of windshield. Take the bottom windshield trim out and look under the black plastic covering bottom corners. If the seam sealer is cracked ,its letting water in. Trust me.
 
That looks like it rusted from the inside out. Previous owner(s) might have left the astroroof /window open in a rain storm and it got soaked, The Original GM carpet is nice and heavy duty but the rubber underside of it makes it very hospitable for rust formation since its hard to dry stuff out after a soaking.
Thats my theory.
I had a astroroof car where I had to do the same.
I'm the third owner. I know the guy I bought it from didn't take good care of the car. I found it on Ebay. The front clip was all chipped and the car had been run hard. Paint was faded and terrible. However, it does have a lot of ATR parts and 89 TA wheels, and an AVC dash. Since buying it I had the motor and transmission rebuilt and put on a new turbo, injectors, front mount, fuel pump. The car is pushing 200k miles.
 
After looking at pick I would check the drain lines on the astro-roof and check and repair windshield seal. I find most time its the windshield and the seam sealer below left and right side of windshield. Take the bottom windshield trim out and look under the black plastic covering bottom corners. If the seam sealer is cracked ,its letting water in. Trust me.

So water is getting in the windshield and puddling in the back seat floor board? Front floor boards look ok. Wouldn't the carpet soak up most of the water before it got to the back seat area?
 
No, carpet is rubber backed and runs under it. Water runs down behind kick panel and than under carpet. Water will work its way to the back floor pans. I can see in the picture water stains. It may also leak from rear glass and run down also. They leak from both areas.
 
Check the astro-roof drain lines to make sure they are free of debri and not
clogged up!


GC
 
They run from the rear corners of the a-roof thru and above the headliner and down the sail panels(b-post)..can look in the trunk around the inner wheel wells and usually see them and trace them back up..or just blow compressed air thru them..however, if it where me i would inspect the rubber hose for cracks and deterioration all the way back up.

GC
 
Water in the rear area is usually the rear windshield or the seam sealer in the trunk area is failing. That is where my water was coming from. Cleaned and resealed those before the paint and all was good.
 
How about just a bad door seal?

Post pictures of the condition of the upper seal. I bet its cracked and leaking water through the window..



..
 
POR-15.... I used to swear by this stuff up here in rusty Upstate NY. Until I figured out what the name meant: Paint Over Rust.

Areas I treated were cleaned well before application. But rust is like a cancer. Unless you get all of the rust,it will continue to 'work' underneath.

In some cars I treated 8-10yrs ago,the POR is peeling off in sheets like a trash bag type of consistency.

Presently I'm using a rust converter on some of my beaters. I feel that is better than covering it. Brands include MarHyde and Duplicolor converter.

It's best to get rid of all of the rust. Even the small surface rust by media blasting,etc. Cut out thin areas. Then paint it.

Luckily my GN doesn't have any rust issues.

I have heard that a company called Eastwood makes a good converter. I've yet to find it.

Steve. '87 GN,t-tops.
 
POR-15.... I used to swear by this stuff up here in rusty Upstate NY. Until I figured out what the name meant: Paint Over Rust.

Areas I treated were cleaned well before application. But rust is like a cancer. Unless you get all of the rust,it will continue to 'work' underneath.

In some cars I treated 8-10yrs ago,the POR is peeling off in sheets like a trash bag type of consistency.

Presently I'm using a rust converter on some of my beaters. I feel that is better than covering it. Brands include MarHyde and Duplicolor converter.

It's best to get rid of all of the rust. Even the small surface rust by media blasting,etc. Cut out thin areas. Then paint it.

Luckily my GN doesn't have any rust issues.

I have heard that a company called Eastwood makes a good converter. I've yet to find it.

Steve. '87 GN,t-tops.

I used POR15 on the underside of my 86 GN about 3 years ago. So far so good. However, I put it on my control arms a year ago on another car and it all pealed off. I applied it the same way, using their metal prep and etching liquid. Anyway, is this the stuff from Eastwood? Eastwood Rust Converter - Convert Rust in One Step
 
Top