How can I fix this rust? First time doing this.

[M3W2]

Just bought my first van, it's a 92 GMC Vandura 1500. Everything seemed good on it, new transmission, engine heads redone, suspension good, the guy told me there were only two little rust spots at the doghouse bolts and I saw them and they looked bad but were small. I got underneath it and checked the whole body, saw no rust really at all from underneath. 

Well I took it home and started ripping out the floorboard and found that the whole area around the doghouse and in between the front seats up to the start of the cargo area has rusted pretty bad. Apparently the windshield has been leaking for a long time and it's rusted from the inside out. I started cleaning it up and have grinded out most of the rust. Now I'm just not sure how to proceed. I've seen some people's recommendations on how to patch hole but that's usually in small flat square areas and this hole is bigger, right over the transmission, shaped strangely and the metal has those corrugated dips.  

Here's a picture of the rusted area
[img=150x150]
And after some grinding
[img=150x150]

If you zoom in on the second picture you can see where I've made sharpie marks where I think I need to cut out the metal. I've never done anything like this before so I could really use the help. Do I need to cut all that out? Or more? How should I repair it afterwards? I was planning on renting a welder and welding some sheet metal onto it somehow. I've never welded before but I want this job done the right way so I don't have to worry about it in the future. Does anyone have advice?

 

[highdesertranger]

yeah rust is like an ice berg, you only see 10% of it.

The correct way to fix it would be to get another piece of floor pan at a junk yard and cut that entire rusted piece out then weld the new piece in. There are several great body work people on you tube with how to videos. There is one Canadian that really stands out as top gun. Make sure to watch many different ones as some are idiots.

In a way you are lucky as far as the finish work as it does not have to be 100% because you will not be able to see it.

Highdesertranger

 

[M3W2]

Is there any way to fix it without having to cut it out of another van? In case I can't find one or they're rusted too. Also when I start cutting the metal with an angle grinder it blows sparks everywhere and I'm next to the engine and everything, should I be worried about anything catching on fire?

 

[bullfrog]

Check Harbor Freight they sell a cheap panel cutter, it might last long enough to get a one time job done. You can rust proof it and treat it with rust resistant paint then fiberglass it but it won't work near as well as replacing the rusty metal with a new panel or rust free junkyard panel. You should always worry about fire and take all safety precautions, Harbor Freight sells welding and safety supplies as well. You might want to get some body shop estimates as it may be easier and cheaper unless you just want to learn to do it yourself.

 

[kklowell]

A good (read bigger) salvage yard will be able to order a new floor panel from a southern state that doesn't have rust issues.

 

[M3W2]

I might call some places but now I have a problem of not having seats. Would putting in a flat piece of sheet metal work somehow?

 

[kklowell]

I wouldn't think so because it will leave some pretty big gaps between it and the old floor where water could get in and puddle. Considering that you've never welded before and would need to rent a welder and either buy or rent other tools, I think you might be happier with the results if you could find someone to do it for you.

 

[bullfrog]

Putting a seat back in is a easy job compared with the repair you want to attempt.

 

[Spaceman Spiff]

I cannot open your pictures to see how bad the rust is, but - I've had good experience with covering non-structural rust with POR-15.  It won't repair the damage but will inhibit further rusting if applied according to directions.

I've done a number of classic and custom cars, some 25+ years without the rust spreading.

P.S. - if you cut or weld around flammable components you need to protect them with fire-proof drapes.  We used a number of wet throw rugs and blankets to cover areas of concern.  Have at least a 10B, C extinguisher handy, preferably halon (dry chemical extinguishers will damage any electrical connections they infiltrate and they are a b!tch to clean up).

 

[JohnnyM]

M3W2,

There's a guy named Chrome Valdez who is a big youtuber out of Vancouver, BC. His channel is vancityvanlife on Youtube. He posts pretty much every day.

He's in the middle of a project just like yours on his older Ford E250. Same problem exactly. He's already posted several segments about his progress.

You could go to Youtube and look him up. Sorry I'm not smart enough to just give you a link.

Johnny

 

[MotorVation]

It really doesn't look all that bad to me. If it were my van, I'd make sure I ground off all the rust then use rust reformer or POR-15 to prevent more, then patch it with some sort of plate without using any type of silicone. I had a new windshield put in an old 4Runner that was rusted around the edges. I mentioned that I had been thinking about sealing around the edges with silicone and the windshield dude told me to never use silicone as it will cause more rust.

He used some sort of thick black urethane when he put the new windshield in and it stopped a good amount of the leaking

my 2 cents

 

[kklowell]

I think this was the first of Chrome's rust repair videos

 

[highdesertranger]

If you use a flat piece of sheet metal how will you get the dog house to seal? highdesertranger

 

[M3W2]

Well the bolts that held the bottom part rusted off the floor so maybe I could weld them to a new flat piece of sheet metal. Or would there be any other way to get a waterproof and strong seal on the sheet metal to the body without welding. With the grooves couldn't I fill them with something or weld some metal into the groove so there wasn't a hole? And then cover everything with por 15 and then paint. Or should I put any kind of rust remover on anything before adding new metal? Thanks for all the help so far. I watched the videos he said the metal he got from a junkyard to fit cost 700 so I would like to try to avoid that if possible. i was thinking maybe something flat could work since besides the grooves it's pretty much a flat area.

 

[bullfrog]

Flat metal won't work well. You may be able to preserve what is there and use some washers or small pieces of metal in the areas where the bolts were with some Rivnuts or nutserts so you can bolt down the dog house, but nothing is as good as what has been recommended which is a replacement metal panel. You should be able to buy a whole or wrecked van for $700, start looking I think you will find what you need for a lot less money.

 

[Weight]

Do not cut anything if you are not absolutely sure you can weld.
Sand, wire brush, and use chemical rust converter, liberally. Patch hole with epoxy. Don't over worry. Someday find an expert that will weld you in a new floor.

 

[Scott3569]

I do not know if this applies to all vehicles..

But you can get replacement floor pans that do not require any welding, it is glued on with a 3m product..

you still of course need to cut out the damaged floor board

 

[rivertrader]

I seen the replacement floor pans at RockAuto I believe they were about a hundred bucks. My 92 floor was completely rotted between the seats as in see-through.I thought I replied to this last night but what I wound up doing was just wire brushing chiseling chippingall the rust off went over it with some oil-based rusty metal primer then the zink paint for like chain link fences and then another coat of the rusty metal primer pop riveted some flat galvanized panels in there for the support down the middle calked the little humps. It's really not that bad get the loose rust off keep the water off of it keep the oxygen away from it
. I got rid of the sponge padding underneath the rubber mat I used the neoprene floor work pads like you get at harbor freight for the underlayment on the mat as they won't absorb water. Another place for water intrusion on these vans is where the bulkhead connector the wires go through the firewall behind the battery it's kind of square build a little shield to go over the top of that so the water doesn't run onto that plug.why did my repair about 2 years ago and it's still holding quite nicely and it's yours is not nearly as bad as mine was. I don't think you need to cut and weld give it a good coat of what I mentioned and keep the water off of it