Former FedEx Truck used as race hauler, how to fix major body rust?

Hi folks, I bought the cheapest running Sprinter I could find, and oh boy, she's got some rust. The frame is all good to my eyes, but it looks like water got trapped behind the trim running along the sides of the van, and it's just rusted apart. You can see light when you're sitting inside the van during the day time (No interior, obviously).

That being said, it really is perfect for my needs. It's full of motorcycles, tools and race gear all summer long, and I don't need it to look pretty. However, I'd like it to be just a tick more respectable in the paddock, and ideally, I'd like to patch the holes and rhino line the whole thing, just because I'm not going to get a real paint job for this thing.

My plan currently is to take a wire wheel on an angle grinder to the major rust spots, hit them with Por 15, and then probably patch it with good West System epoxy fiberglass, then spray it with rhino liner. I am capable of welding (though I don't currently own one), but I am certainly not "a welder".

It's an imperfect situation without a perfect solution, but I wanted to see if anyone had good suggestions for my situation. "doing it right" would cost more than I spent on the van, and I could just drive it as-is until it throws a rod through the block then scrap it, but if I can put in a few hundred bucks and some elbow grease over the winter, to get a slightly less embarrassing rig for the next few race seasons, I'm in.





 

Kajtek1

2015 3500 X long limo RV
Now I see what some understand under "rust bucket".
For heavy corrosion on heavy equipment I was always starting with rust converter.
You can buy it online as not too many local places might carry it.
This is a chemical, who converts rust into compound who makes protective coating. That needs to be painted after, but good start and eats the corrosion who takes lot of time to remove mechanically.
I am a welder, but welding thin fenders is different welding than welding 1/4" plates, so that is different skill. I know in Europe you can buy repair panels, who will go over original panels to form new skin. Did not see them in US, but worth checking.
Have fun.
 
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lindenengineering

Well-known member
The you need to learn tinmans welding using oxy acetylene torch, with #1 or 2 nozzle set to 1 to 1,5 psi of gas mix.

Methods handed down to me from Jim H, RFC aircraft mechanic/machinist 1914 to 1918 .
That bloke could even weld up a alum beer can with an oxy torch.

I still use that method today with some additional tips I learned from Indians & Iranians on stretching & shrinking sheet metal body panels.
For thousand years of "doing metal" make these people the maestros !
Dennis
 

DougE

Member
Remove loose rust and treat with Ospho. It will seep into the crevices and convert the rust to a paintable surface. This was my basic prep for my roof seams.
 
Thanks for the input guys, I'll see if this works better to host the photos (Second photo shows the sliding door shortly before being replaced with a used-yet-much-cleaner version, and a hilarious joke written on the side):

https://imgur.com/a/bwHWfB8



I'm really hesitant to go after the welding unless I do it just for the sake of learning/practicing a new skill. I think I'll try the suggested rust converter, patch the literal holes, and spray it with rhino liner to limp another few years out of her until the main drivetrain starts failing. If I had wanted a good, clean sprinter, I would have spent $15k on one. I think the patch-and-spray is the right balance between modest improvements, and diminishing returns territory.
 
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Kajtek1

2015 3500 X long limo RV
Once you have rust converted and painted - you can patch the holes with fiberglass.
It will look ugly, but at least add some integrity and will prevent from dirt accumulation.
I feel really sad thinking how much rust prevention could do a touch-up stick used 4 years ago, but then you might have to spend more money for better van.
 

Midwestdrifter

Engineer In Residence
How do the rear spring perches look? The structural stuff is the most critical (although all the body is structural to some extent). That body damage warrants bonding or welding in repair panels. Bondo will not last long, and you will have very little to hold it on anyways.
 
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Bertn

Member
I'm working on my first sprinter, also almost the cheapest I could find lol and I can tell you that the wirewheel on your angle grinder will make the holes very big very fast :)

Good luck with the project. Is it worth putting a lot of time into it in terms of miles and mechanical condition?
 
How do the rear spring perches look? The structural stuff is the most critical (although all the body is structural to some extent). That body damage warrants bonding or welding in repair panels. Bondo will not last long, and you will have very little to hold it on anyways.
Everything underneath is nice and clean. The body took some hits, but the frame and underbody seems rock solid. I'd consider welding, but most of the damage is behind the trim pieces along the side, and I know those trim pieces won't go back on right if I start pulling them off. I'm afraid that "doing it right" means spending more than the van is worth, what do proper repair panels cost? Do you have more guidance on how exactly to go about something like that? There's a far difference between epoxy fiberglass and Bondo, for the record.

I'm working on my first sprinter, also almost the cheapest I could find lol and I can tell you that the wirewheel on your angle grinder will make the holes very big very fast :)

Good luck with the project. Is it worth putting a lot of time into it in terms of miles and mechanical condition?
It's at about 260k miles, and the transmission is new. I plan on pulling a few more seasons of race hauling out of her.
 
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Midwestdrifter

Engineer In Residence
A good fiberglass repair will do the trick, its labor intensive for good looking results though.

One option, though not very good looking, is to bond partial repair panels over the damaged areas. Take the repair panel and trim it for about 2" of overlap on good metal. Abate the rust as needed. Then use body panel adhesive to bond the replacement panel directly over the damaged area. Very strong and fairly low labor.

Door bottoms can be rebuilt using chopped fiberglass and resin. Then sand/grind to the right profile. My experience has been, that once you start removing the rotten metal, you may find a lot less left than you expect. Some folks will just apply the resin/glass right over rust to "encapsulate it". This will not bond well. At a minimum you need to mechanically remove the loose rust, then treat with a neutralizer.
 

72chevy4x4

Well-known member
wow, that's a piece of work!

POR15 was supposed to be some incredible stuff for going overtop bad surfaces, but for your rig I would probably wire wheel the flaking material off, phosphate/etch the metal (convert and prime) then hit it with an appropriate primer.

Rhino-spray sounds like a good avenue, except you kind of need the entire body covered. here's a video I watched sometime back-kind of interesting and shows the steps. There's a lot of work involved in fixing her up.

https://www.youtube.com/watch?v=Y_OtN3gItf4
 

showkey

Well-known member
The problem with Sprinter rust it’s different than other vehicles, where you cut out the effected areas and weld in new metal. Bottom of a door, dog leg or bottom of 1/4 panel.

Sprinter is similar to bone marrow cancer. It’s every where, like the top of the year doors, windshield frames, blisters the size of soft balls ! The base metal lacked proper surface treatments and galvanize from day one. Similar to old of the lates 70’ early 80’s Toyotas, Honda and VW.......once the rust started there was little hope and repairs were not practical. These manufacturers had buy back programs on rust effected vehicles.

Think the OP Sprinter might need 50-100 patch panels as a starting point ?
 
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Zoomyn

Member
POR-15 is the be-all it's claimed to be, and it does best leaving fine rust attached so it acts as rebar to the POR concrete action...

EXCEPT.. . it pulls back while curing from sharp corners (even second/third coats follow memory of first) and it is necessary to wait until naptha carrier has evaporated and the poly is starting to kick before putting another coat, or the top finish coat on; nothing sticks to cured POR-15 not even POR-15 - if you plan on taking three or five hours painting that first coat then it is immediately begin the second coat and repeat that same pattern - then it's time for the top non-POR coat so that will be able to key in and give something for body filler to get bite into, anyhow - count on ten or twelve hours to do three coats, even if its two hours painting and ten hours of waiting.

POR needs the extra coats because it is almost as thin as mineral spirits and can have a lot of drop-outs and bubbles in the metal/rust and or thin spots where it got wicked in/away that need recoating. Oh - the fumes while the catalyst is actually kicking (while we recoat) will give a cheap rum hangover the next day so stay upwind...

Blah blah I know but... https://www.amazon.com/dp/B00FSE6PJ8 <--- zinc phosphate w/ zinc chromate primer, aerosol can, soak can in hot water to keep propellant pressure up so it keeps spraying - only good for aluminum and iron... keep overspray from traveling, even 1/2 of 1 percent chromate is bad news, discard drop cloths, same for sanding dust... This might be a better alternative to POR-15 for base coat that body filler is going to hide anyhow...
 
The problem with Sprinter rust it’s different than other vehicles, where you cut out the effected areas and weld in new metal. Bottom of a door, dog leg or bottom of 1/4 panel.

Sprinter is similar to bone marrow cancer. It’s every where, like the top of the year doors, windshield frames, blisters the size of soft balls ! The base metal lacked proper surface treatments and galvanize from day one. Similar to old of the lates 70’ early 80’s Toyotas, Honda and VW.......once the rust started there was little hope and repairs were not practical. These manufacturers had buy back programs on rust effected vehicles.

Think the OP Sprinter might need 50-100 patch panels as a starting point ?
That's a piece of what I'm thinking, if she's too far gone to save "properly" I might just hit the horrible spots with a wire wheel and a neutralizer, then blast it all with rhino liner, and carry on with a mad-max machine. Hell, I could just rivet sheet metal stock over the horrible holes, and lean-into the aesthetic of an apocalypse machine. Sure beats spending hours on the appearance of a machine that doesn't matter.

Oh well, I got it cheap enough that I'm not losing much when she winds up in a junkyard in three years.
 
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