Watch Bob repair a crashed £70k Audi RS3 chassis by cutting, fitting, and welding a donor panel in this detailed repair tutorial.
Key Takeaways
- Chassis repairs require precise measurement and alignment using fixed reference points.
- Thorough cleaning and removal of sealants is critical before welding to avoid fire hazards.
- Patience and adaptability are essential when unexpected issues arise during repair.
- Using donor panels can save a salvage vehicle by replacing only damaged sections.
- Preparation and fitting are as important as welding for a professional finish.
What the video covers
- Bob receives a crashed Audi RS3 from Saving Salvage needing chassis repair on a damaged door seal area.
- The damaged door is removed despite difficulties with painted bolts by heating to clear paint.
- Bob uses donor parts from an undamaged quarter of a similar car to replace the damaged chassis section.
- He carefully measures, marks, and aligns the donor panel using hinges as datum points for precision.
- Cutting and cleaning are done meticulously, including removal of waxy sealant to prepare for welding.
- Bob encounters minor setbacks like a splinter injury and a cutting mistake but adapts his approach.
- A detailed welding process follows with tack welds for alignment and final joining of panels.
- Bob emphasizes thorough prep work, cleaning, and fitting to ensure a clean, professional repair.
- The video includes a sponsored segment promoting Huel food as a convenient meal during busy work.
- The repair is completed successfully with only the outer skin replaced, avoiding major chassis cuts.
Chapters
- 00:00Introduction and Project Overview
- 00:45Removing the Damaged Door
- 01:35Planning the Repair and Using Donor Parts
- 02:44Marking and Measuring for Cutting
- 04:49Cutting and Cleaning the Panels
- 06:08Sponsorship Break and Quick Meal
- 07:40Fitting and Final Trimming
- 08:25Preparing for Welding and Tack Welds
- 11:54Final Welding and Repair Completion
Full Transcript — Download SRT & Markdown
Speaker A
Hello everybody. Welcome back to our channel. Today, I'm going to be working on this BMW, Skoda, Audi, Audi. A nice one. But, what we have to do [music] We've had a call from Dean at Saving Salvage and he says, "Bob, I need your help. We bought a crashed Audi RS3 and what he's done, he's replaced the brakes and wishbones and all the other mechanical bits there, but [music] what he can't do is repair the damage to the seal here.
Speaker A
The door has been damaged, but we're going to get rid of that because he's going to put a new one on.
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We have this. This is a quarter of an undamaged car and [music] our job is to try and take this section out of it, the undamaged section, and then weld it into the car. So, I don't know how I'm going to do that yet. I
Speaker A
never really have a plan. I just throw myself in the deep end and figure the rest out.
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[music] First things first, we need to get this door off. Oh, nothing fits. Oh, you cars. The bolt holding the door on is full of paint and I can't get this thing, socket, whatever it's called, into it. So, I'm going to heat it up and
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burn all the paint out of the way. [music] Okay. So, now [music] the door is off, it's time to have a real look at the job.
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Even though it's a small amount of damage, it's going to make a lot of mess. So, we start with masking off the interior to keep all the dust out.
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Before we get in too deep, me and my cameraman Jay are just going to prep the donor part.
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I can do this. Oh my god, this is weird. How are the turntables? Is this what it's like to be Bob?
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[laughter] Love it. Cinematics. This is easy. Okay, so now we're the right way round.
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What are you thinking? I'm looking for lines and datums and shapes and things that are common on both pieces, on this and the bit of scrap we have over there.
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[music] Uh so I can ta- start taking measurements and then start cutting. That's all so far. I I've not come up with the rest of the plan. Look at that for a bit and then take a wheel off and
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then look at that again and then do something else and look at that again and then I'll formulate a plan in the background.
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This has been crashed. [laughter] I'm not joking. It's all dented in. Oh my god, it is.
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But that doesn't matter for now. We'll come back to that later on. Next step is to get the wheel off and get it stored [music] safely away from the car.
Speaker A
What have you just found, Bob? [laughter] So we didn't need to take those bolts out.
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Bob's top tips. Uh Didn't even need to. Because I'm not a mechanic. So I'm going to use these hinges as a datum because I know that this and this, because they're riveted in, are going to be in the
Speaker A
same place on both pieces. So if I come out about that far away from that part of the hinge, that's where the damage stops. So all I need to do is measure from that point to that point. So I just need something
Speaker A
about that size. Now we transfer the same mark onto this using the same points.
Speaker A
And I imagine you're only going back to this point here for ease and convenience.
Speaker A
Mm no, because that would be really hard to weld to because that's loads of pieces sandwiched together. It's going to have a lot of paint and stuff on the inside.
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So we keep to flat surfaces. So I don't know where it is going to be yet, but I'll probably come across like that.
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Down like that to there. And then weld around because that's an easy surface to [music] weld to.
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This is why you're the welder and I'm the cameraman. I can do that as well.
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I'd like to see you edit. Don't tap don't Do not challenge me. All right. Let's actually get back to what I know, metal.
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Now I need to transfer the lines from one piece to the other. And [music] using these pieces of angle iron, I can make sure that the lines are exactly where they need to be. Now that's done, I can finally start cutting.
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Now I've got the majority of it cut out, I need to start cleaning the area.
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[music] This inner skin is full of this waxy sealant stuff and it needs to be fully removed before we start welding because it could go on fire or make some other kind of mess.
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Ooh. Got a splinter in my arm. What you doing, Bob? OOH! THAT WAS A BIG ONE.
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I'm going to have to blur it but I can see this aftermath. Mhm. The fact that that was There was just that much sticking out of me.
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Oh my god. [laughter] This is why we wear safety glasses. Explanation time. So, I've removed the majority of the damage just to see what it's like on the underside of the frame. So, I was kind of worried that I'd have to cut
Speaker A
this whole section out. It's actually just the outer skin, which is ideal. We're going to start straightening some things up. There's that little dent in there that will get covered over so you won't be able to see it from the inside
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of the car or the outside of the car, but I know it's there. So, I want to take care of it and make it right.
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And then start cutting this shape out of that one to match up to there.
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Hopefully [music] without getting any more metal in me. Anyway, we need to get this panel cut out. Following the same steps as the last piece, we get the flex angle grinder on the job.
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[music] Easy. Huel is boring. [music] Like and subscribe. We need to do a final trim after it's clean, but now here's 3 hours of me cleaning. [music] We are clean.
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Guess what I've got? I've got Huel food. I've been so busy fixing this car today, [music] I kind of forgot to eat. Terrible habit of mine, and if you're like me, you probably do the exact same thing. [music] So, the
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only option for me to eat at the moment is the local 24-hour place that we don't like to drive through too often. So, my alternative is Huel food. And believe it or not, this [music] is actually the healthier option. It's got 26 vitamins
Speaker A
and minerals, and more protein in it than one of your protein gym shakes. It's high [music] in fiber, no added sugar, and gluten and lactose-free.
Speaker A
These two are my favorite flavors, fresh berry [music] and happy banana. So, if you want to try this ready-to-drink complete meal, go on the website and type in Bob-YouTube for 5% [music] off on top of the 30% off from the
Speaker A
summer sale. So, thank you very much to Huel food for sponsoring this video. Now, let's get back to it.
Speaker A
So, it's mostly trimmed up, except I even I make mistakes. This one I can't hide in the edit.
Speaker A
[laughter] I've cut this wrong. So, whatever I did up here with the measuring and the ruling stuff, there's a like an 8-mil gap there, but we'll figure it out. Right, so next thing I need to do is trim it up
Speaker A
and make sure we get all the bits of metal like lined up nicely side by side because that makes it very, very easy to weld. If we don't do that, then it just gets really messy and it's more likely to burn holes
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in things and just be awkward and horrible and annoying. And the quickest and easiest way is to do just this.
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We can mark around it. That's how much I need to cut off. Easy. So, why is your grinder so long? I've got to ask.
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Well, so this is actually got a very specific use. It's for getting into like really tight spaces and stuff. But, I'm using it today because it was the first one I picked up when I went next door and it's
Speaker A
not as weirdly as it looks. It's actually quite nice to use. You can kind of nip things and hold it like that and I'm actually quite enjoying using it.
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Flex tools. This panel still needs a fair amount of work. So, more of drawing, more cutting, more grinding, more cleaning all these different surfaces until we have a perfectly clean fitted [music] part.
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Now, onto cleaning the inside. This part is also covered in this waxy sealant stuff. So, it needs [music] to be perfectly clean before we weld it. So, after a few hours of cleaning, that is everything done. Both the new [music]
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part and the chassis. But, there's one more thing we have to do before we get this welded back together.
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So, we need to take this dent out. And I'm going to pull it out. So, I'm going to weld this little stud here to the center. I'm going to heat around it and pull the stud.
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[music] [music] [music] And just like that, t
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[music] [music] [music] And just like that, the dent that will never bother anybody is gone.
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[music] So, another quick cleanup and then we can fit the outer skin back where it should be.
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Bit of a gap. Ooh, I um got a bit too excited. What I should have done is cut this a bit longer and laid it over and then marked around it.
Speaker A
Oh, well. I've got a solution. I've cut out some little bits of steel that are the same thickness as the body panels. So, we're going to tack weld these on behind the original body panel, then put our new panel on top of these,
Speaker A
almost like a little shelf. Before we put this piece on, there has been a little bit of damage to the side of this sill. Um we think it [music] was from where it was strapped down to the bed of the truck, but doesn't matter.
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It's damaged, we need to straighten it out before it goes on, otherwise it's pointless doing it.
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[music] [music] So, even though this is actually all covered in trim, we will know it's there and if I don't have it perfect, I won't be able to sleep.
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Like every job I do, the majority of the work is prep. I spend so much time making sure every piece is as clean as it can be. I'm using the first few tacks to perfect the alignment of the outside
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skin. So, I chase it along, either pushing the steel in or levering the steel out to ensure alignment. Every time I make a tack, it warps the area beside it.
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This seam was also in the crash, but fortunately, it was only bent and I could pull it back out.
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All that's left to do is to give everything a good clean, dress the welds [music] back, and get it ready for paint.
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[music] It is done. It was a thoroughly enjoyable experience. [music] [music] The keen-eyed of you will notice these little dark patches here. That's actually a dip in the metal. When we're welding steel, still I don't like it.
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It's very hard, but when it welds, it starts to warp and move and do weird stuff because of the heat expansion and contraction.
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And typically, what you'll find is on one side of the weld, you'll get a low spot. What that looks like is you'll have a piece of metal there, a piece of metal here, a weld in the middle, and because one side will expand and one
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side will contract, you'll tend to see it go like that and up like that. So, you get your high spot, which can be hammered down, but your low spot can't be hammered up unless you can get around the back of
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it, but we're sealed up around the back of it. So, you always get a slightly lower side when you're MIG welding on this sort of stuff. Now, that happens the majority of the time.
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Um some people that can or want like perfect panels and stuff will like drill holes in the back and tap it back out again and just get it absolutely perfect and not have any filler in it, but you
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know, realistic scenario, a light little skim of filler. I mean it's like I can barely even feel that. I can just about like feel with my nail.
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So we're looking at like point two of a mill of filler. It's not going to worry anybody. It's going behind the skirt.
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It's fine. It's perfect. So that was a lot easier and faster than I was expecting. We didn't need to cut any lumps of the chassis out which I'm very very happy with. It was just that outer skin of the chassis. So did what
Speaker A
we needed to do and as I said went fast then happy. If you want to follow more on this build pop over to see Dean on Saving Salvage. His channel is really really good. He goes really into depth
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with a lot of Volkswagen Audi stuff. So if you like what we're doing we do a lot of chassis work on super cars and other bits and pieces. So [music] make sure you hit that like and subscribe button
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and I'll see you soon.
Topics:Audi RS3chassis repaircar weldingsalvage carcar restorationauto body repairmetal fabricationcar repair tutorialwelding techniquescar panel replacement











