Do it in a day: Floor / Jacking point repair

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So you have a daily driver that needs attention, or a project that needs work but you don’t have a lot of time to get really stuck into it? Why not figure out what jobs you could do in one day. Apart from the normal maintenance jobs like: Oil service, suspension greasing and brake adjustment, what could you do in a day?

My LHD some of you know. This car was imported back in February and transported back to the UK by my friend Martin Wallis. Since being in my workshop very little has happened to it, apart from being put on axle stands – I’ve even had it for sale both in the Club’s magazine and website but it hasn't sold. No one seems to want projects.

The car is extremely solid and only needs a couple of little bits of body repair to make the shell 100%. My task for today is to cut out and repair where someone in the past has used the car’s jacking point and it has lifted up through the floor a little. This is a common area that needs attention in most old 70s BL cars, especially Marinas. With this car I have been lucky that the rest of the floor area is spotless and it only needs a small patch letting in.

Tools for the job (these are what I used – you can substitute to suit).

Socket set (removal of front seat)
Screw drivers (removal of trim)
Welders blanket (if leaving some interior in place
Block of wood
Body hammer
Sharpie pen
Tin snips
Cardboard (corrugated)
Cut off wheel (or grinder with a 1mm cutting disc)
Flapper disc (40 grit)
Masking tape
Sandpaper (coarse grit) or Die grinder with attachment wheel
Drill (with wire brush attachment)
Spot weld drill bit
Various drill bits
Workbench and steel for forming
Ruler
16 or 18 guage steel plate
Weld-thru primer
Zinc rich primer
Body matched paint
Cavity wax
Seam sealer

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  1. Remove front seat, carpet retaining strip and carpet

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2. Remove underfelt and protect trim with welder’s blanket

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3. Inspect affected area – use block of wood and hammer to knock jacking point back (make sure to check integrity of jacking point first).

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4. Clean area around jacking point with sandpaper and mark sport welds.

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5. Mark area to be repaired with masking tape.

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6. If the jacking point is to be replaced, carefully drill out spot welds – be sure not to go through both levels!

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7. Using a cut off wheel (or angle grinder with 1mm cutting disc) carefully cut along your marked lines. We will be attempting a butt weld repair here as it will be neater, if you are replacing the complete jacking point you can do a lap joint and seam weld or plug weld the panel into the floor.

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My repair will be in two pieces as I want to try and retain the original look from under the car – I am also plug welding this plate onto the original jacking point.

8. Clean up both sides of the floor and be sure to clean out the original jacking point with a wire brush attachment if you are keeping it.

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 9. Make a template from corrugated cardboard: A simple way here is to cut a piece of cardboard about the same size as the area to be repaired – press it against the edges of metal – turn it over and you will have a base to start your template!

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10. Cut and trim cardboard to suit – if butt welding, make sure you leave a small gap all the way around (roughly about 1 – 1.5mm).

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11. Paint all areas with weld-thru primer (once in bare metal).

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12. Transfer cardboard templates into metal using tin snips – trim to suit as necessary.

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13. Here I have drilled the top piece of my repair so that I can plug weld it to the bottom piece. I have also re-plug welded the original spot welds after I removed some rust from them.

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14. Once you are happy with the fitment of the patch spot weld it into the floor making sure not to overheat the repair. You should alternate your welds across the patch until they look like a continuous seam weld.

15. Clean up the welds as you see fit.

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16. Prim bare metal with a good quality rust inhibitor primer.

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17. Use seam sealer to protect welds.

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18. Prim area on both sides with a zinc rich primer

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19. Paint to match body colour

20. Wax cavities with a quality wax