Repairing rust in floor boards: Grassroots Motorsports forum: Grassroots Motorsports Magazine

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May 29, 2008 11:47 a.m. Wade None

This is on my 88 mustang lx.

I had posted this a while back, before the change. It looks to be mostly just surface rust, but there are a few cracks which I have been told are pretty common for these cars. Most of the mustang guys have the cracks welded up. There aren't any holes that I can see.

I'm hoping that I can get in there with a grinder or a wire brush and clean most of it up, then use some kind of sealer or primer. I'm building this car to autocross and do track days in, so I'll be adding a set of subframe connectors with cross braces.

Does this look like it can be repaired like that, or do you think the floor boards will have to be cut out and replaced. I'm building this on a challenge car budget, so if new metal has to be welded in, then it is going to eat up more of my budget than I had hoped for.

Here are the pictures.

Driver side

Passenger side
May 29, 2008 4:08 p.m. Dwight Varnes SuperDork

Hmmm. The general nature of the rust you have isn't that bad. Wire wheel and POR-15 should make quick work of it unless you blow through it somewhere. Then the best solution is to weld in some patches. The cracks (I'm so glad I talked myself out of a Fox chassis Mustang) should be welded up, really. This is just a floorpan, so the repairs don't have to be sexy nor is there a whole lot of 'structure' there other than mounting the seats. My BMW had a few spots of rot and I just cut some bits out and welded a few patches in with my MIG. I suck at the welding, but nobody sees it (even without the carpet).
June 2, 2008 1:41 p.m. Xceler8x Reader

I've heard those 5 spd 5.0 'Stangs crack around the seat posts on the drivers side. Is that where your crack is?
June 2, 2008 1:54 p.m. ClemSparks SuperDork

It's not just the 5.0 models, for the record...

First hand experience here with a 4 cyl.

Clem
June 3, 2008 8:31 p.m. Eldukerino New Reader

My rule of thumb with replacing floorboards is if I can stick my pocket knife through it it should be replaced. I doesn't look to bad but I would test the bad areas with something sharp. If its good just clean off all the surface rust and POR-15 it. And get the cracks welded up for sure!