Mathilde - Traction Restoration Part 2 - Front floor section

baldrick56

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Let me introduce Mathilde, my 1953 Traction Avant. For the record she’s an RHD ‘Onze Normale’ with the ‘Perfo’ engine, dark blue when she came my way but originally silver once I’d delved into the paint layers. I’m going to make this post multi-part (for different subject areas) since it would be too long in one go. This section deals with the floor panel ahead of the seat mounting box-section and its junctions with surrounding panels.

In the first of the series I talked about the tools and equipment and chasing my tail to upgrade the things that weren’t so useful. One thing that got neglected in all this was my camera that despite being a child of the ‘noughties decided it really wanted to exist in the sixties – it didn’t do mind-altering drugs but bathed every image it captured in a psychedellic purple hue, apologies for that in advance.

Considering the floor my dilemma was that the P.O. had already done some repairs. A flat sheet had been trimmed very accurately to shape but only pop-rivetted in, and that to largely rusted out / failing sections. I hummed and hawed for ages, looked to see if I could get the preformed ‘wrinkly’ panels – they didn’t seem to be available. In the end I decided to leave the repaired sheet but to “sandwich” it around the edges with new sections securely fixed to the rest of the shell. Aft of the seatmount the floor was ‘serviceable’ with a fair bit of surface rust and failing bituminous paint that was a complete pig to remove.
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First piece was the rear of the panel abutting the seat mount, I fabricated a full width angle section from flat sheet with projecting ‘tounges’ to stitch into the inner-sills.
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The same theory was applied to the sides with the difference that the “upright” flange of the angle needed to be larger as there was corrosion on the inner-sill to “bridge.” On the nearside I must have had ‘beginners luck’ in spades because I fabricated a tall-legged angle to a curved profile on plan and it all fitted {with a bit of hammer “persuasion”}.

Flushed with success I tried the same technique to the offside and what a disaster – soon as I got it right in section it was out on plan or longitudinally. After bashing it back & forward for hours I scrapped the piece and started again.
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This time I cut two ‘flats,’ one parallel sided, one curved to the plan floor profile {cardboard template}, tack welded them at right-angles then seam welded along the join when I was happy with the fit. Result – perfectly aligned panel with no distortion.
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(The paint you can see in some of the pics is 'Camweld' "weld through" primer - thoroughly recommend this or the equivalent as there's no way of painting these surfaces post-repair)

........ TO BE CONTINUED .......

Disclaimer - other than as a customer I've no connection with any brands mentioned in the text

Happy fixing,
Rob
 
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Lots of work. I'd love to see the pics of the jambonneau work you did - once the quota resets. That's one of the first jobs I'll have to tackle. (well, after the obligatory battery box rebuild - just to get my feet wet).
 
Rob, you keep referring to the car as a RHD 'Onze Normale'. Is that for the sake of our American and European fellow enthusiasts? It should really be called a 'Big Fifteen' as it came out of the Slough factory.
 
Rob, you keep referring to the car as a RHD 'Onze Normale'. Is that for the sake of our American and European fellow enthusiasts? It should really be called a 'Big Fifteen' as it came out of the Slough factory.
I stand corrected - never really sure how to describe it, I guess I'm angling towards what you need to call it {or pretend it is) if you go "shopping." By which I mean all of the suppliers (AFAIK) are European based, if you start talking about 'Big Fifteens' with them you then have to clarify its not the 6 cylinder half the time :unsure:
 
OK - second section following above (needs to be two otherwise photos won't post);
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completing the picture were two smaller-legged angle sections that went under the floor to provide an “edge” to fix the outer sill/rocker panel to. These I managed to get from a single piece of sheet – think because the legs were smaller it didn’t tend to distort so much.

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Another area that was ‘rotted out’ was the bulkhead where the inner leaves of the ‘jambonneaus’ curve around to meet in the middle. Surmising that this area (at least in theory) is potentially subject to high load {the weight of the back half of the engine would largely be transmitted into the shell at these points}, I fabricated wide-leg angles curved on plan to reinforce these areas {also used thicker sheet here – 2.0mm I.l.o. 1.6}. Not entirely trusting the replacement floor at the rear edges of these after careful measurement I ‘through drilled’ to expose the flanges of the triangular stiffeners running the length of the floorpan and plug welded new panel / replacement floor / stiffener together.

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Continuing that last concept and again with the thicker sheet I “bridged” the gaps between my inner jambonneau brackets and the seat mounting cross-piece tracing the lines above the chassis stiffeners and through-drilling / plug welding it all together {used a bottle jack under the triangular stiffeners to gently apply pressure to “sandwich” the layers whilst welding}.

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Thats it I think – one “new” {sort of} floor

Disclaimer - other than as a customer I've no connection with any brands mentioned in the text

Happy fixing,
Rob
 
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