The hole in the floor gang.

[Liquid Knight]

I've given tips for doing this but never done a guide so here we go.

Disclaimer: This is how I do it on my driveway and not necessarily how a professional mechanic would.

The aim here is an M.O.T standard repair not a concourse restoration.

First step when welding a hole in the floor of a car is get it up on ramps, lift the side you are welding and rotate the ramp 180 degrees. This is safer than any axle stand/jack combination I have ever seen.

Next disconnect the battery.

Find and inspect the hole you need to repair.

Make sure the interior carpet is lifted out of the way.

If you need a fire extinguisher bigger than this get someone to help or someone else to do it.

Cut away as much rubbish metal as possible. As this is a Fiat make sure you use a sharp flat bladed screw driver to remove as much of the crazy glue as you can.

Clean about an inch around the hole. Remove all of the underseal, paint, crazy glue, muck, grease and crap. The cleaner the surface the cleaner and better the weld. Seriously for an hour job like this forty minutes is getting ready, five minutes welding, ten minutes painting and five minutes tidying up.

If you're a bit of a nerd (like me) you can take a moment to get a brass rubbing of the odd Lancia symbol you might find.

Cut, shape, tack on a plate ( you can now seam weld inside if you like but I haven't due to lack of space and the suck on soundproofing stinks). Seam weld around the outside about an inch or so at a time pausing to make sure the interior isn't on fire. This also affords you an opportunity to fine tune the shaping of the plate as it may distort a little during the process.

You can flap it flat if you like but I prefer to leave the exposed welds. Let it cool and paint inside and out.

Put the interior back, reconnect the battery, take the car off the ramps and tidy the bits of rust and crap off the floor. Job done.

 

[Liquid Knight]

So that was underneath today I've repaired a hole from inside the car.

Same as before, get the car up on ramps, jack up the side you're working on and turn the ramp a hundred and eighty degrees so it's out of the way and the car will not roll. Disconnect the battery and this time I needed to get the back seat out before lifting the carpet.

Guess what torx bit I needed...

...but for every problem there's a solution.

Here's a top tip. If you need to undo the seat belt place a clamp on it with a little slack so it doesn't wind up and become an issue later.

The previous repair had been done but not all the rust was cut away at the time and the soundproofing was put down on wet paint. Arse! :bang:

Chisel as much of that crap out of the way as possible.

Clean as much as possible before you decide how much to cut out.

It's even more obvious this wasn't done properly in the previous repair.

Make a plate a little smaller than the patch you have cleaned so you can lap weld along the outer edge of the plate on to the floor.

Now using features under the car as a guide, cut as much rusty metal out as possible.

So why clean first? The black plastic stuck on the floor bloody stink, gets everywhere and will burn and make a load of smoke if you don't get as much out as possible. Chisel chucks, wire brush bits and then carefully grind out with a brush.

Lap weld around the inside. Same drill as before. weld a few inches and check underneath for fire.

This will leave a nice edge to lap weld from under the car...

...paint, tidy up and that's job done.