Chassis repair steel

[Howard Wright]

Hi All

Grovelling under the Green Van last week I noticed a strange vertical line on the near side chassis leg just behind the brake cross shaft.  Further examination revealed some serious corrosion skilfully hidden under globs of underseal and a crack.  


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  IMG_4633.jpeg (Size: 114.13 KB / Downloads: 337)

I did wonder if I could repair in situ but I’ve taken the plunge and am removing the body.

The corrosion is visible from just aft of the front cross shaft to just before the spring housing although I’m sure more will be revealed when the body is off.  Strangely the offside of the chassis looks to be in reasonable condition.

So how would forum members go about repairing this?  I’m assuming that new steel will have to replace old but what steel would be best to use (ordinary mild steel or something higher yield).  I’m tempted to weld a 38mm square box section into the U shape chassis profile.

But if someone has a good condition near side short wheelbase chassis leg in their shed?

Cheers

Howard

[Colin Bromley]

I have some experience of chassis repair, building, and extensive modification, none of which was done on Sevens. I would cut out the bad section and find someone who can bend up a new section of ordinary mild steel, to the correct profile, before welding it in. On C section chassis in the past I have welded diamond shaped plated to the vertical faces over the welded joints, or made up another C section that fits inside, this was welded all the way round, and had several 3/4" holes drilled in it, to enable a series of large plug welds.
So I think your idea of replacing the rot & welding in a box as a strengthener sounds like the right way to go. Tacking in the box before you cut out the bad section would have the added benefit of everything aligned while you weld in the new bit.

[Ivor Hawkins]

Is that a Cherry Bomb in your exhaust system Howard?

[Howard Wright]

Is that a Cherry Bomb in your exhaust system Howard?

Yes!

[Ian Williams]

I would make or have made a top hat reinforcing section that fits snugly inside the chassis rail in question. I would weld the crack and then hot rivet the reinforcing section inside the chassis rail. This has been a successful and pragmatic repair that my friend Joss Campbell carried out on a couple of chassis, it also dosen't look out of place, or out of period.

[Chris KC]

First thing I'd do is get it right back to bare metal/ rust so you can see the extent of the rot. 
If that means getting the whole frame blasted so be it.
If you know someone with a scrap frame which could be pillaged for a repair section it would make life very easy.
Yes, even then I would think about a reinforcing plate of some kind, unless you are very confident in the welded repair. 
It's not something you hear of much these days but my frame was sprayed with zinc and that seems to put a stop to further corrosion.

[Hugh Barnes]

In the past, I have strengthened a frame by welding in a section of square shaped tube of the appropriate dimensions as you are considering.

[Ivor Hawkins]

Is that a Cherry Bomb in your exhaust system Howard?

Yes!

You hot rodder!

[Howard Wright]

Is that a Cherry Bomb in your exhaust system Howard?

Yes!

You hot rodder!

No, just a skinflint.  The system cobbled together from tube, mandrel bends and the Cherry bomb is way cheaper than a full exhaust from our Cherished suppliers.  Although it is not for the purists!

Cheers

Howard

[Reckless Rat]

Bummer, Howard. Look on the bright side - at least you won't be bored this winter. Hope it all comes good in the end.