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MG MGB Technical - Replacing MGB Foors

My MGB's foors need to be replaced.
Is there any book or documentation giving details to proceed? (or web site)? Weelding is not a problem but my problem is about removing pan and to be carefull about fuel line, brake line, wiring ...
Thanks
Paul

Cehck the archives of this BBS. There is a TON of info as this is topic is addressed several times a year. Also try locating a copy of Porter's DIY Guide to mgb restoration. Basically you're going to cut out the flooring material and leave a half inch or so lip around the crossmember, supports, and outer framing. The gas, brake, and other lines run under the pasenger floor and can be dropped out of the way- but you still need to watch out for them.
william fox

Paul, you might try this link.
http://www.middlebank.co.uk/Floor.htm

Regards,
Dennis
D F Sexton

Hey Paul,
Completed this task last year myself. The best helps to me were, This board, The lindesy Porter, DIY Restoration book and a workshop manual. Mine is a Haynes Manual. Lots of websites out there too. Just Google MGB restoration, or MGB floors and sills, etc.

The best place to start of course is complete removal of carpet, seats, and sound deadner. Get the car in the air, on stands or if you are industrious a rotiserie. Get a good look at how the pans are attached to the sills, crossmembers and tranny tunnel.

Get several spot weld cutters or low angle drill bits.
If you wire brush the painted and welded surfaces the spot welds show up pretty well. Start drilling them spot welds! A reciprocating saw or jig saw with a couple of metal blades help with the process as well.

I used a reciprocating saw to remove most of the sheet metal, then drilled out the spot welds. I used a chisel and two pound hammer to break the remnants of the welds. The floor sections cut out in three big pieces or in my case a million shards of disentigrated ferrous oxide. The wiring and fuel lines should be hidden under the ledge, just be careful when cutting that area. Once down to sill ledges, tranny tunnel ledge and crossmember, clean the ledges up, If they are still there. Fit your new floors. The expensive ones come with all studs and welded nuts, If I had been smart I'd have bought these. The cheap ones have the advantage of having a turned up section that can serve to replace rusted areas of ledge, but you have to weld the nuts in first. (I couldn't figure out exactly were the nuts would go within the raised section of the floor because my seat rails were also disentegrated, so I welded in a piece of 1/4" iron strap. When I was ready to put the seats back with new rails, I simply marked the location drilled and tapped the iron strap.

Punch or drill a hole every couple of inches along the edge of your new floor, lay it in with a few self tapping screws or pop rivits to get it down tight and commence to welding. (MiG welding is the way to go here) Once you've done one side do the other.

Courage, Paul! Courage! Have patience with the spot welds, there are HUNDREDS. Keep a sharp bit in your drill and they'll go faster.

Of course this is the condensed version of how it goes. Figure a couple days of drilling welds after the main portion of pans are gone. Another day of cleaning the ledges to BARE METAL, rust doesn't weld worth a hoot. One more day of spot welding and grinding.

And another months worth of waiting for parts, repairing the holes in the sill that you'll likely find, Letting your fingers heal (WEAR GLOVES AND EYE PROTECTION, rusty eye hurts!)
Allow for frequent 12oz breaks, and the inevitable scowl from the wife as you track in rust particles and tar etc.
Not a painless process but one that can be accomplished with persistence and patience.
Good Luck!
TDHoward

Paul,

There is a booklet still available by most suppliers that was printed by "Practical Classics" and titled if i remind exactly " MGB Restoring and uprating". There is a complete photos sequence explaining step by step the way to proceed in for a DIY .
Good luck!
Renou

Gentlemen
Thanks for your answers and your recommendations.
I have just to do it!!
Paul
Paul

I recently did full sills and lower fenders on both sides along with partial floorpan replacement.

If you dont have them I would reccomentd the following tools:

Air Chisel - If you do the floors in the middle of winter, the wide chisel will make short work of the tar like sound deadener. It becomes brittle and te rapid hammering of the chisel busts it out lickety split. and; (2) the aggressive way to remove welds - cut out the middle of the floor with a four inch angle grinder and cutting wheel. Once you have trimmed back to the lip the floor rests on, use the air chisel to lift off the top strip which used to be the outer edge of the floor. I grabbed the start of the strip with a vise grips while using the air chisel to bust out the successive welds. I did one side with a drill and bits and a chisel and lump hammer - manly man work with lots of banging, beer swilling and swearing. Then the second side with an air chisel - like buttaaa. But the air chisel can do a lot of damage in a hurry if mis-applied

Then dress the lip with a hammer and dollyclean it up with an angle grinder and grinding wheel and wire brush it prior to welding.

Item number 2 - a 4 Inch Angle grinder with (a) metal cutting wheels; (b) Grinding wheels for dressing down welds and exposing old spot welds), and; (c) Wire wheels for cleaning the metal bright and immaculate for welding in new pieces. Get the wheels - particularly the wire wheels- from a welding suply store - much sturdier than the harware store variety (less likely to throw little wires in your eye) and meant for doing serious harm to the metal in a hurry. I'm happy with my Dewalt angle grinder and have been unable to kill it. Definitely screw it the removable handle when cutting metal to hold the grinder steady. The cutting wheels don't like to be jerked sideways while cutting and will express their displeasure by shattering into bits of flying cutting wheel.


Item number 3 is a neat but not essential toy. It is an air powered combination punch and flanger for $40. Great for punching all those little panels for spot welds and making flush fitting lap joints on patch panels. Harbor freight tools has it cheap: http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=41696


I'm an idiot and take way too many risks, but this is one situation where you will be wearing heavy work gloves, eye protection and a disposable mask or you will be bloody and blind in no time.

Regards,

Brian C.

Brian Corrigan

I find wire wheels as a tremendous waste of time, sweat and money.
The composite fiber impregnated hard nylon wheels are the only way to go. These go right through the rust like it wasn't even there, whereas the wire wheels will do little more then turn the most tenacious of the rust black.

They can be found in most hardware stores..and do not bother with the sandpaper wheels..these are even more of a joke.
jegawatt

I have done four floors like Brain describes and seems to work well. A recipricating saw with metal blade is also good for a rough cut of the floor. Just watch lines under pass. floor. Then use air chisel as described. Ear protection is a must.
Kirk Knutsen

Don't forget that after you have cleaned up all the edges, drilled the holes in the new floor pans etc to paint all seams with weld through primer. That way at least you are giving maximum protection to the inside of the joint even if you do seam seal inside and out after final cleaning & painting
Iain MacKintosh

This thread was discussed between 26/07/2004 and 02/08/2004

MG MGB Technical index

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