Quarter floor fitment (especially rear)

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moggy1960
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Quarter floor fitment (especially rear)

Post by moggy1960 »

Hi all.
Just after a bit of advice on quarter panel floor fitment. The front quarter floor edge has a joggle on the sill side edge to allow the floor to be simply dropped in against the inner sill step and on top of the chassis leg. The rear quarter floor then is shaped to the transmission tunnel shape with then a high back to weld to the heel board. However there is no joggle on the rear quarter floor sill edge. When the floor is dropped in on the rear it fits nicely but how much overlap have people left of the original floor? Mine was very badly rotten so I literally just have the inner sill floor flange. There just seems a large step underneath from underneath from the inner sill edge to the new floor panel. Do people on here seam weld the floor from inside the car and underneath and use of a seam sealer? Originally the floors would have been sandwiched between the inner sill and under sill front to rear but originally also the floor had the undersills attached to them. Just wondering what peoples experiences are for these drop inside floor replacements? The sensible thing would of to put a joggle on the rear floor edge like the front quarter floor has.
Many thanks
Dave
moggy1960
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Re: Quarter floor fitment (especially rear)

Post by moggy1960 »

I suppose what I'm trying to say is that it's going to be impossible to get a flush floor fit with the original floor edge. unless I cut the new floor quarter to get a butt joint fit. But that means joggling the heel board high back corner edge too. The heel board high back drops straight onto the original heel board flange. So I guess I'm going to have to live with a step from the floor edge I've cut out to the new floor panel.
Dave
mogbob
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Re: Quarter floor fitment (especially rear)

Post by mogbob »

Dave
If you're going down the concours route then spend hundreds of hours ( & £££'s ) taking it all apart , panel by panel , and reassembling to achieve perfection.
In the real world the vast majority work with what's available. Having got involved with 5 restorations classic and vintage I haven't yet fitted a repair panel that didn't need tweaking in some way shape or form.
Stick to the essentials , decent clean metal to weld to and a strong neat pleasing joint to look at.

Will I metaphorically " slap you on the back , for a job well done " when I see your photos of your work ? Of
course I will , good on you. If I ever get to see your car , in the flesh , will I insist you remove the seats , carpets ,seat belts , underlay ,etc so I can inspect the quality of your welding ? I'm sure you would have an appropriate response for me ! You are your own quality inspector.

My first restoration confession time. Having spent years welding up , working anti-clockwise I came back to my first section.... although I thought it was great at the time , my standards had improved. There was no denying it, it was rubbish , I took it apart and did it again.
Crack on Dave , you'll get there.Good luck with it and don't forget to enjoy it.
Bob
Mark Wilson
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Re: Quarter floor fitment (especially rear)

Post by Mark Wilson »

Not sure how much you are doing to to the sill structure, but on mine I was replacing most of it. I repaired the flanges, including welding an angle to the foot of the seat upstand, then plug welded the floor edge extensions to the bottom of the sill step flange from above (bit perverse, but I was working with the car normal way up at this stage, and don't like weld dripping on me...). I trimmed the floor edge extensions flush with the flanges, then plug welded the quarter floor to the top of flanges - I'd cut off the side and rear upstands from the repair panel. I later replaced the floor under the seat as well, and plug welded this to the underside of the repaired seat box flange. As you say, quite a thick step at the three panel joints, but when I eventually turned the car over I welded a thick fillet to finish the joins and after grinding and applying seam sealer it looks fine.

I was trying to make everything as original looking as possible, but agree with Bob about not getting too hung up on originality.. We did have someone on here many years back who made his own floor panels including the floor edge extensions in one piece - but didn't ever seem to finish the project...

1. Floor extension below flange
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2. Extension trimmed flush with flange
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DSCF7075 (Small).JPG (81.58 KiB) Viewed 4455 times
3. Edges prepared to receive floor
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DSCF7173 (Small).JPG (85.32 KiB) Viewed 4455 times
4. Panel ready for plug welding
DSCF7172 (Small).JPG
DSCF7172 (Small).JPG (89.84 KiB) Viewed 4455 times
mogbob
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Re: Quarter floor fitment (especially rear)

Post by mogbob »

Nice work Mark ! I'm a West Country lad , so " proper job ".
Bob
GavinL
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Re: Quarter floor fitment (especially rear)

Post by GavinL »

Looks good. i'm curious about plug welding this panel in place - my understanding was that perceived practice is that plug welding is ok where spot welds existed before, but butt or seam welding is preferred when repairing partial panels. Whilst this sounds logical in principle, i would have thought that a soundly plug welded joint is preferable to a badly welded butt weld, and from personal experience my plug welding is definitely better than my butt welding in thin sheet!

Not meant as a criticism, just a fellow amateur restorer seeking guidance.
GavinL
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Re: Quarter floor fitment (especially rear)

Post by GavinL »

Looks good. i'm curious about plug welding this panel in place - my understanding was that perceived practice is that plug welding is ok where spot welds existed before, but butt or seam welding is preferred when repairing partial panels. Whilst this sounds logical in principle, i would have thought that a soundly plug welded joint is preferable to a badly welded butt weld, and from personal experience my plug welding is definitely better than my butt welding in thin sheet!

Not meant as a criticism, just a fellow amateur restorer seeking guidance.
mogbob
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Re: Quarter floor fitment (especially rear)

Post by mogbob »

The only time a "third party " gets involved is if the car is subject to an MOT and the area in question , typically
around seat belt mountings, suspension and steering mounting points, areas affecting structural integrity , and loose bits of jagged metal likely to injure pedestrians / passers by is involved. Where in these areas , factory seam welding was utilized , the MOT man / woman would expect to see the " same again " in any repairs. If you're in any doubt ask an MOT man /woman what is required in that area. A tester is not a lover of any sub standard welding...... be it spot , plug or seam
With plug welding , close distance , will provide strength. Some people will be belt and braces , seam welding in addition. It may not " seal " the joint completely and generous seam sealer application prior to painting will prevent water / damp penetration.
Gavin have you / do you use brass strip behind the joint when butt welding ? It stops the weld blowing holes through the sheet metal by acting as a heatsink. Obtain some strips , of various lengths about 5/10 mm thick,
10 /15 cm long is normally sufficient. I've filed down some bits to put curvatures into the metal. That way you can tuck them right into the joins. The usual prep : - good clean metal , degreased and your brass strip clamped up really tight behind the join. At a push you can flatten old copper piping with a big hammer / club hammer. It's better than nothing. If heat distortion is an issue , the usual advice of keep moving about applies , allowing the heat to dissipate.
Dave with apologies for going off piste with your thread.
Bob
Mark Wilson
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Re: Quarter floor fitment (especially rear)

Post by Mark Wilson »

Gavin, butt weld v lap or plug is always a matter for debate, so not taken as criticism. My butt welding is no better than you say yours is, but I have used it where I felt it appropriate, eg floor panels (home made) below the seat box, and extensively in the inner wing and flitch area. On the floor panel in my pictures the sill step and seat box flanges, and the crossmember, were originally spot welded to the one piece floor pan, so pretty much as original, plus a lap and a seam for extra strength! The join with the tunnel could possibly have been butt welded, but I didn't want to remove any strength from the tunnel area, and it would have been beyond my skills to cut and weld a flexing panel with multiple curvatures. And the laps were seam welded both sides - here's the evidence m'lud!
Attachments
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volrod544
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Re: Quarter floor fitment (especially rear)

Post by volrod544 »

I was trying to make everything as original looking as possible, but agree with Bob about not getting too hung up on originality.. We did have someone on here many years back who made his own floor panels including the floor edge extensions in one piece - but didn't ever seem to finish the project...


might be me youre referencing ? been doing a bit more recently - but agree that trying to get originality by making panels takes a lot more time than buying repair panels - its quite a learning experience
Mark Wilson
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Re: Quarter floor fitment (especially rear)

Post by Mark Wilson »

Hi Volrod. Yes, it was you I was referencing, and great to see you back on here. I hope my comment didn't come across as disrespectful in any way, as I remember thinking your skills and attention to detail were absolutely amazing. With my much quicker and dirtier methods I still haven't "quite" finished, after nearly ten years!
Redmoggy
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Re: Quarter floor fitment (especially rear)

Post by Redmoggy »

Just a thought, but how about buying the quarter floor and the extensions. Cut out the edge section under the sill step and weld in the repair panel. Now trim the edge of the floor repair so you can seam weld them together creating a one piece panel that replicates the original. If your concerned about your ability to seam weld try holding a thick chunk of copper or brass beneath the seam as you weld.

My recollection of the MOT regs is that you can only replicate original spot welds, where a panel is cut and joined, like the join between your floor repair and trans tunnel, it must be continuously welded but can be either a lap or butt joint. How much this now matters with many classics being MOT exempt is anyones guess.
kevin s
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Re: Quarter floor fitment (especially rear)

Post by kevin s »

I didn't like the repair panels on offer because they were not the original design and I loathed paying for something I was going to have to cut up so I decided to replace the factory construction making the panels myself. Forming the base of the sill was quite a struggle though particularly around the rear where the outer weld flange doubles back on it's self.
The method I used was :

- Replace the lower 1/3 of the inner sill and boxing panels with hand formed L shaped sections seam welded in to re-create the original weld flanges
- Fit a off the shelf rear spring hanger repair panel seam welded to the floor and plug welded to the inner sill and bixing panel.
- Make and fit the outer half of the floor and base of the sill seam weld to the floor (inner half of floor was ok) then plug weld to the base of the sill and boxing panel.
- Fit a off the shelf outer sill.
- fold up a L shapped section to replace the front of the back seat crossmember.

The result is by no means perfect (I don't believe in grinding seam welds flat as it reduces theif strength so they show) but it's strong and has no extra double skinned areas to corrode.
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Re: Quarter floor fitment (especially rear)

Post by Redmoggy »

Kevin, I cannot think of a single reason why grinding the top of the weld bead would reduce its strength. The floor is only 18 gauge steel so a competent welder should have no problem with getting the weld to penetrate through the join, grinding the surface weld bead will then only reduce the thickness to that of the surrounding steel. However, each to their own.
kevin s
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Re: Quarter floor fitment (especially rear)

Post by kevin s »

If you are a perfect welder welding perfect steel and can guarantee 100% penetration with no inclusions you could be right but when welding 60 year old steel that's unlikely, some countries even insist you over plate a butt weld in structural members.

I've seen the results of crashes with back street repairs and butt welds ground flat to hide them, it's not pretty.

Modern cars do use laser welded blanks assembled from new steel in highly controlled enviroments, very few of us can can re-produce this at home.
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Re: Quarter floor fitment (especially rear)

Post by Redmoggy »

As I said, each to their own. You would however hope that those of us repairing cars to convey our own family members and not just to make a quick few quid would take the time to learn. When I was taught to weld, some 25 years ago, I was told that a decent weld, even with a MIG should require very little finishing. If you have a large weld bead on the surface then the chances are the weld did not get hot enough to flow into the joint meaning that it's only really attached ( Poorly ) to the surface of the metal. That is much more dangerous than a decent weld that has been properly finished. As for welding to old steel, if its clean, solid and grease free you shouldn't have much of an issue.

Gusseting a butt weld is something that would usually be required on a chassis member made from much thicker steel than you would see in a monocoque construction. N/Z is also one of those countries that require you do so, both seam welding and plug welding a diamond shaped plate over the repair / join.
kevin s
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Re: Quarter floor fitment (especially rear)

Post by kevin s »

To be clear I was meaning on the structural elements like the sill structure, chassis legs and around the torsion bar mountings, not everywhere.
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