Wheel arch 'rules'

[Jimmyhorns]

Dear All

I am currently 'rebuilding' the rear wheel arches on my 2007 Sprinter, which have essentially rotted away.

I have a patch panel for the outer skin to weld into place, and am planning to do this with plug welds, by cutting out the existing good metal and leaving enough to form a lip with an air joggler. If necessary I can also seam weld the join, but with less risk of burning through. So this bit I think I have sorted......

For the inner part of the arch/well, this is made currently of two sections, a crescent shaped piece that sits between the outer skin and the inside 'panel wall' of van, and then the inside 'tub shaped piece.

I am finding it difficult to work out what the 'rules' are on replacing this - it would be a lot easier to form a single piece to make the 'cresent' shaped piece and the inside tub to weld to the patch panel that I have sourced, but from an MOT / roadworthyness point of view do I need to recreate exactly what was there originally?...

Many thanks

James

 

[daedalusminos]

Photos would help!

For the outer repair patch, I would strongly recommend butt welding, joggling can promote rust and it doesn't work too well on curves. Spend time with a good fit (1-1.5mm gap) and the butt should work well.

 

[Jimmyhorns]

Photos would help!

For the outer repair patch, I would strongly recommend butt welding, joggling can promote rust and it doesn't work too well on curves. Spend time with a good fit (1-1.5mm gap) and the butt should work well.

Yeah, photos would definitely help. I have now attached. Forgive me for my wording, I dont know the correct terms, and just try to describe as best I can.

 

[Jimmyhorns]

So my plan is to do nothing more elaborate internally than to cut a piece of sheet steel into a rectangle, so it can be flexed into the space that I have labeled 'width of arch'. At its top will be the inner panel (2nd photo) which it will be welded to with a fillet weld, which essentially forms a semicircle that I have drawn in the 3rd photo. at the end of the sheet, both fore and aft it will be welded to the floor.

I will then close off the well/arch from the load space of the van with a semicircular sheet.

I will then form an appropriate bridging structure to bring this newly formed structure to meet where the patch panel will attach.

As you can probably tell, I have not done this before, and am just trying to feel my way through the process. There is so much rot in the bits I have cut away while they are not beyond salvage, so much work would be required to patch, I believe the above would work better, if it is of course allowed.....

 

[Jimmyhorns]

As for the joggler, there are not any curves for it to need to work on. But I take your point about potentially encouraging rust due to the lip formation.

 

[minimutly]

Rust in the repair - hah, do you think it will make any difference? The rest of the van will have long dissolved before it becomes an issue.
Technically I believe any structural repairs have to be continuously seam welded, wheelarch repairs arent structural are they?

 

[steveo3002]

dont cut it where you put that red line ...keep it small only cut out whats needed and keep it below that swage line

id go for butt weld around the repair join , spot welds where factory did it , tbh if you dress down the welds and seam seal it and underseal no one is going to pick at it

 

[steviec_lj]

As above, only cut out what you really need to. That way you can replace it again in future should the need arise.

Butt weld with a series of tacks or short runs to avoid blowing through. Make sure the inside gets a liberal coating of seam sealer, smear some filler on the outside to fill any pin holes or low spots after you grind back the welds, bit of primer, top coat and jobs done.

Sounds simple really, but it never is. The job will grow arms, legs and another head if you’re not careful

 

[Jimmyhorns]

dont cut it where you put that red line ...keep it small only cut out whats needed and keep it below that swage line

id go for butt weld around the repair join , spot welds where factory did it , tbh if you dress down the welds and seam seal it and underseal no one is going to pick at it

Ah yes, I hadnt thought about the issues with cutting into the swage line and trying to get it to look reasonable - thanks for that.

Butt welding means that I need to cut super accurately, and I am not sure that I have the skills for that yet, hence the joggler and plug weld plan......


My main worry is not with the outside, but with the inner 'tub' or 'well'. It will look very obviously non original. I dont really have the ability to put any bead rolls in (I dont have a bead roller for one).

I am struggling to find the 'rules' on whether a repair has to look the same as the original, and have the same mechanical design......

 

[steveo3002]

doesnt need to have swage lines built in on inner arches etc ...like i said do a neat safe job , cake it in underseal and no one will care to much

yeah about the joggling i expect it will last out the rest of the van plenty of people do that just get some cavity wax inside

 

[Munkul]

never mind the rules, they aren't all that definitive.

From a practical point of view, if its not a structural member, then anything goes, as long as it fills the whole arch and you can't poke a screwdriver through it anywhere. No-one cares about swage lines etc, as long as it's not going to fall apart.

From an ethical point of view, the above still applies, but make sure the welding is half decent.

Even if it's a structural member, people always get away with cutting and patching in, as long as it resembles the original.

If it looks good, it's probably good.

 

[Robotstar5]

.......Butt welding means that I need to cut super accurately, and I am not sure that I have the skills for that yet, hence the joggler and plug weld plan......

Just cut the repair panel slightly oversize then dress back to fit with a grinder/flapwheel.

 

[Jimmyhorns]

never mind the rules, they aren't all that definitive.

From a practical point of view, if its not a structural member, then anything goes, as long as it fills the whole arch and you can't poke a screwdriver through it anywhere. No-one cares about swage lines etc, as long as it's not going to fall apart.

From an ethical point of view, the above still applies, but make sure the welding is half decent.

Even if it's a structural member, people always get away with cutting and patching in, as long as it resembles the original.

If it looks good, it's probably good.

Im going to start a project thread on here I think.... That way I can be critically appraised

 

[slim_boy_fat]

From a practical point of view, if its not a structural member, then anything goes, as long as it fills the whole arch and you can't poke a screwdriver through it anywhere. No-one cares about swage lines etc, as long as it's not going to fall apart.

And make sure there aren't any sharp or 'sticky-out' bits which could injure anyone passing.

 

[anto]

Ah yes, I hadnt thought about the issues with cutting into the swage line and trying to get it to look reasonable - thanks for that.

Butt welding means that I need to cut super accurately, and I am not sure that I have the skills for that yet, hence the joggler and plug weld plan......


My main worry is not with the outside, but with the inner 'tub' or 'well'. It will look very obviously non original. I dont really have the ability to put any bead rolls in (I dont have a bead roller for one).

I am struggling to find the 'rules' on whether a repair has to look the same as the original, and have the same mechanical design......

Make the repair panel first (if possible)
Line up with the old panel and trace around the new panel. That will give you a nice clean line that matches the new panel.

 

[minimutly]

If you have a joggler use it. On the inside I have used cardboard to create templates, a big hammer to create curves sections, and continuously welded any overlapping sections. So long as its sealed properly it will outsee the rest of the van - your not doing a classic resto are you?

 

[Jimmyhorns]

If you have a joggler use it. On the inside I have used cardboard to create templates, a big hammer to create curves sections, and continuously welded any overlapping sections. So long as its sealed properly it will outsee the rest of the van - your not doing a classic resto are you?

definitely not a classic resto - its a 2007 sprinter! It just needs to be functional and pass MOT etc. Thanks for your advice.

 

[Waitesy]

Hey man! How did you get on with this? I’m currently doing exactly the same

Cheers

 

[slim_boy_fat]

Hey man! How did you get on with this? I’m currently doing exactly the same

Cheers

Hasn't been on here since Oct 2019 so I suspect little help there.

 

[Shedendman]

Hasn't been on here since Oct 2019 so I suspect little help there.

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