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Frame Rust Repair Suggestions


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My MJ has some significant rust damage. 

 

I've never welded or done any fabrication before so I planned on learning as I go, using the floorboard repair as an opportunity to practice. 

 

I'm nervous about the rest of the body though. I think the structural integrity of the vehicle is compromised due to the rust. I can see one of the POs tried to reinforce the frame by welding on some medal plates, but by my estimations it is insufficient. I have been driving the jeep around town but I hesitate to haul anything of significant weight. 

 

Floor 

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MCMVZ2J.jpg

 

Frame/structure 

Near leaf shackels

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I can peel away and make the holes bigger by hand. 

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I'm looking for some input on the significance of this damage, and what you guys would recommend in terms of just taking the truck in (an auto body shop, machine shop, etc.?) to repair the frame for me. It's a project MJ that I planned on restoring to it's former glory anyway, but assessing the damage I think it's a bigger project than I'm prepared (or qualified) for. 

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Ouch!

 

Learn to weld.

 

Seriously. It's not so bad that it can't be saved, but you'll pay through the nose to have a body shop do it. You can buy a hobby-grade MIG welder and teach yourself to weld for a LOT less.

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That will be a big job to fix.

 

It will cost thousands is you pay somebody to do it.

 

So learning to do it yourself will be the only reasonable way...  It's going to be a lot of cutting stuff out and making big patch pieces.  The floor will the be the least critical part.

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If you are planning to restore I would try to find a clean roller and build off of the clean frame . Depending on where you are at you may find a roller for a good price, paying someone to fix all that rust will cost a good amount of money . Once you have a clean frame / unibody and transfer all the parts from your rusted truck to the clean frame you could then sell the old frame to someone that wants to build a off-road rig and he'll probably have a welder etc and the rust won't be a bid deal for him to fix . 

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6 hours ago, Strokermjcomanche said:

If you are planning to restore I would try to find a clean roller and build off of the clean frame . Depending on where you are at you may find a roller for a good price, paying someone to fix all that rust will cost a good amount of money . Once you have a clean frame / unibody and transfer all the parts from your rusted truck to the clean frame you could then sell the old frame to someone that wants to build a off-road rig and he'll probably have a welder etc and the rust won't be a bid deal for him to fix . 

 

Good plan, but that's not restoring the truck he's got, that's restoring the other truck.

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I went to Tractor Supply and bought a 110 welder just for my keeps. Necessary item if you own a jeep! Couple YouTube videos and I was off. Remember if it don't look good you can always grind or cut to try again

Sent from my SM-G892U using Tapatalk

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44 minutes ago, Eagle said:

Good plan, but that's not restoring the truck he's got, that's restoring the other truck

 

Yes, that's exactly my dilemma. Other than the rust on the frame, this MJ is in really good shape. Body is very straight, color is very nice, motor and tranny are < 100,000 miles.

 

I got the MJ for next to nothing because it had severe death wobble and some oil and exhaust leaks that I had no issue resolving myself, but wasn't aware of the severity of the rust until I joined this forum and saw other horror stories. I'd be reading a thread about someone's rust bucket situation and realize, "Oh, my MJ looks just like this guy's!:D 

 

The pictures I posted are pretty much the worst of it. It didn't seem severe to me at first, but now I know better, and don't want to put myself or someone else at risk.

 

I'm just bummed out now. I'm was thinking about just getting rid of it, but I love the Comanches and it's hard to get rid of something simply because of inconvenience or because it's more work than I expected. That's why I ask for your opinions, so thanks for giving my something to think about. 

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The MJ frame rails are fairly thin steel, so you don't need (or want) a super high-power welder or you'll burn right through rather than welding good steel to what's left. With some practice, you could get the job done with a $100 flux-core, 120-volt wire welder from Harbor Freight Tools. Like this one: https://www.harborfreight.com/Flux-125-Welder-63582.html

 

That said, you'll get much better welds with less difficulty with a MIG welder (gas shielding). I've seen some 120-volt MIG welders, but not recently. If you have a 240-volt outlet in your garage (or spare capacity in your breaker panel to add a dedicated 240-volt outlet), then this one would be a better choice: https://www.harborfreight.com/170-Amp-DC-240-Volt-MIGFlux-Cored-Welder-61888.html

 

You can also do the job with a stick welder, and that would be cheaper for the machine. I don't know if others would agree, but I think stick welding is harder to learn. Part of it is knowing which electrodes (sticks) to buy -- there are MANY choices, and each is best suited for particular applications.

 

To properly repair your frame, you'll need to remove the bed and gas tank for access. Good idea anyway -- the idea of welding next to 20 gallons of gasoline makes my hair stand on end. See if there's a technical school or community college near you that has a welding class you can sign up for.

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My suggestions.

 

Buy a decent MIG welder.  Lincoln, Hobart, Miller, etc.  Go with one that is 220V or dual voltage, so that you don't outgrow the machine if you decide to do other things later.  Plus if this doesn't work out, the resale on quality 220V machines is a lot better.  You can always turn the machine down, but you can't turn it up past whatever the highest setting is.  Buy a good automatic helmet, they're relatively cheap now and make life way easier when you're wiggling around under a truck.  Get some good gloves, and a jacket is probably a good idea.  A fireproof welding blanket is also a good idea.

 

Then don't start with the frame repairs.  Build some bumpers, patio furniture, modern art, fix other random broken things, face some lawnmower blades, etc, to get a feel of how the machine works and what a solid weld is.  Once you're making good welds on a variety of thicknesses or materials, in different positions, etc, then do some more practicing and destructive testing of what you've welded.  It's much easier to screw up welds on something that doesn't matter, and throw it out, than it is to cut/grind off a repair you welded incorrectly underneath a truck.

 

Then you can start on frame repairs.  Big things to remember are to prep the metal meticulously, it is zinc coated from the factory and will contaminate the welds, and make sure your repair is large enough that it extends well beyond the damage to suitably spread the load.  Cardboard is great for making templates, and getting the best fit of the pieces will make the welding easier.  Use a combination of rosette (plug or spot, essentially) welds, along with perimeter welds around the repair pieces.  Straight vertical joints are to be avoided when lapping from the repair to clean metal, an angled joint is better, or a fished or 'fishplate' joint.  Make sure you cut out the severely rusted/damaged areas as otherwise they will want to cause more rust to start in the future.  Use a weld through (zinc) primer on all pieces that are to be overlapped or inaccessible after welding; this primer will not contaminate the weld but offers some protection against rust.  Eastwood makes an inner chassis coating paint that comes with a long flexible spray nozzle so you can paint the inside of the repairs afterwards, I would recommend using that or modding up a garden chemical sprayer to do the same thing.

 

I don't know what else you have for tools, but I'd recommend a couple decent angle grinders for cutting and shaping repair pieces, a die grinder with some rotary burrs,  a wire wheel and some scotchbrite/sanding rolocs to prep the frame (a cordless drill can do these things too, it's just slower), a good selection of C-clamps and C style vicegrips, some bar clamps (honestly, you can never have too many clamps), a good drill (drillpress is better, even a small one) for putting holes in for rosettes, basic handtools (sockets, wrenches, hammers, files, etc), and a good selection of PPE beyond what I mentioned before (good hearing protection, face shield, respirator, safety glasses, thinner gloves for working steel, good hard toe boots so when you drop half the thing in your shop on your toes it doesn't hurt).

 

I'm sure I'm forgetting lots of useful things, but that's my advice in a single page.

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I did alot of research before buying my first welder.  Dirty Comanche hits all the same points I'd mention.  Except the welder choice.  A decent Hobart, Lincoln or Miller 110V 135-140 amp Mig welder is all you need for your Jeep.  You won't touch the power on a 220V model when doing anything on the MJ.  Eastwood makes a very good Lincoln clone.  Stay away from Harbor Freight and choose to use gas instead of flux wire unless you've got to weld outdoors in wind.

 

Plan on spending $500 on the machine, $200 on gas and welding wire and another $200 on safety equipment including a fire extinguisher.  Toss in more cash for clamps and brushes and a welding cart.  A 4.5" angle grinder with cutoff wheels will get the rot out quickly.  You don't need torches but they're nice to have.

 

You've got to practice on other stuff first.  Then start with your frame.  Save the floorpans until later, they require thin wire and way more finesse.

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I'm not convinced on automatic dimming masks for beginning. They're definitely convenient, but if you've got some lesser skills and you loose your arc, or you're constantly stopping and starting, my eyes kinda hurt a bit by the end of the day when I was learning. But definitely go for quality masks... Your eyes are pretty important. 

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5 hours ago, kryptronic said:

I did alot of research before buying my first welder.  Dirty Comanche hits all the same points I'd mention.  Except the welder choice.  A decent Hobart, Lincoln or Miller 110V 135-140 amp Mig welder is all you need for your Jeep.  You won't touch the power on a 220V model when doing anything on the MJ.

 

I use the upper range of my MM180 all the time building stuff for my Jeeps, YMMV, but I do wind up building a lot of things out of 1/4"-3/8" and it's nice to be able to weld them without making multiple passes or exceeding the duty cycle of the welder.

 

With all tool purchases I believe in NOT buying the bare minimum, because I've done it too many times and hated the results and subsequently spent more money to buy what I should have got in the first place.

 

This Eastwood welder is IMHO a hell of a deal: https://www.eastwood.com/eastwood-mig-welder-175-amp-with-spool-gun.html  $500 for it vs $300 for the 110V version, but you get a spool gun and a lot more oomf.  A spool gun is nice for the odd time you need to glue some aluminum or stainless back together, or even to run fluxcore/dualshield in for doing farmer repairs on stuff around the house (saves respooling the machine and wasting wire). 

 

Now if a guy didn't have a 220V outlet, or doesn't want to jump in with both feet, certainly that 110V one will do that job and could be resold later if it turns out to be inadequate.

 

1 hour ago, gogmorgo said:

I'm not convinced on automatic dimming masks for beginning. They're definitely convenient, but if you've got some lesser skills and you loose your arc, or you're constantly stopping and starting, my eyes kinda hurt a bit by the end of the day when I was learning. But definitely go for quality masks... Your eyes are pretty important. 

 

Turn the sensitivity and speed up on it the mask if you're having trouble with that.  Make sure it's the correct shade too.  To me it's easier for the beginner because it's one less thing to worry about to not be flipping the mask up and down or hitting/holding a button, or you're not trying to peer through a fixed shade mask and can't make out where your work piece or the torch is.

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