MGB Floor pans '71 MGB

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GaryBeu

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• Dec 16, 2009

• #1

Well, we are ready to start on the replacement of floor pans. First thing, of course, is getting the old ones out! Can someone give us some guidance and some "what NOT to do's"?

Tony, you mentioned awhile back that you could walk us through it and explain how not to have to weld them...we'd appreciate the assistance.

Any suggestions on who to order from? Any preference between Victoria British and Moss?

Thanks for any help.

 

Mickey Richaud

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• Dec 16, 2009

• #2

Gary -

Other than ensuring that you put in a brace so the body doesn't fold in on you, I'm not much help. But if you find you need a crossmember as well (# 17 here ), I have a new one left over from the restoration I did a while back.

Mickey

 

OP

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GaryBeu

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• Dec 16, 2009

• #3

Thanks Mickey. I might need it since one of the jack channels is pretty much destroyed. How do you go about bracing when you cut them out?

 

Mickey Richaud

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• Dec 16, 2009

• #4

Cross-bracing fore and aft of the doors is the usual method. I'm sure someone here has done it and has some pictures to share.

 

Mickey Richaud

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• Dec 16, 2009

• #5

I have a couple of books on body restoration at the house. I know one of them covers this. If someone hasn't chimed in before I get home later today, I'll check them and get back to you.

 

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GaryBeu

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• Dec 16, 2009

• #6

Thanks Mickey and here are a couple of photos of the floors as they are.

 

Mickey Richaud

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• Dec 16, 2009

• #7

Looks like you have your work cut out...

At least your engine has the torque to twist the radio console 90 degrees!

 

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bob67bgt

Jedi Knight

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• Dec 16, 2009

• #8

Passenger side should not be a problem. When you get that driver side out be sure to rustproof the inside of the frame rail. I have seen some pitted pretty deep from debris holding moisture in there. I have not seen a MGB that needed bracing to put floors in. As a side note I would NOT glue floors in. If you are working with a new car and perfect conditions it would probably be fine. I welded floors in my daughters MGB and about 3 years later it was hit close to head on. The car twisted like a pretzel and the floors did not give way. 99% of the time you will never have to deal with a crash like she went thru. I would have felt real bad if the floors were glued in and the outcome was worse! Good clean metal and lots of plug welds. Rant over and my 2 cents added. Bob

 

Mickey Richaud

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• Dec 16, 2009

• #9

with Bob. If it's only the floor pans you're replacing, bracing probably isn't an issue. Just grabbed the book I mentioned earlier, and there's no mention of preliminary bracing. Sill and crossmember changeouts will be a different animal, however.

 

bill_young

Jedi Warrior

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• Dec 16, 2009

• #10

I replaced the floor pans on a friends '72 a couple of years ago. It's not too bad a job if the sills are in good condition. Two types of replacement pans available, Heritage and Steelcraft. The Heritage pans have all the little studs, water drip holes, and other hardware attached, the Steelcraft pans didn't and I had to fabricate all those. On the plus side the Steelcraft pans had more extra metal around the edges so if your sills or tunnel show some signs of rot that extra material might come in handy. I didn't need any bracing as the sills on that car were fine. If the car body gaps around the doors don't move when the car is on jack stands and the doors are opened then I think you'd be fine replacing the floor pans without any door bracing which will definitely be in your way if you have to use it. The actual step by step is too long to go through here but if you conatct me I'll be happy to write it up and e-mail to you. I didn't take any photos of the process, that I regret, but it's not hard to explain.

 

tony barnhill

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• Dec 16, 2009

• #11

1. When you cut the old floors out, leave about 1" around all edges & crossmembers.....I cut mine with a little $30 air saw from Harbor Freight.

2. Clean the 1" lip with some type grinder so there's no paint left on them - do not put anything on them.

3. Decide which type 2-part glue you want to use.....a visit to your local autobody paint supply hous will help lots....tell them you want to glue 2 body panels together.

Call me in the morning when you've gotten that far.

Oh, 1 side at a time.....I don't get excited about cross bracing if all I'm doing is the floor.

 

DrEntropy

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• Dec 16, 2009

• #12

What Tony said.

And:
I took a LOT of time to evaluate/torture the SEM panel epoxy. Was truly reluctant to accept it as strong enough. I'm a reformed "metal mite" N.D.T. type (second generation mill rat steel worker), skeptic/cynic. I impact tested, mauled, bent, pulled and basically tortured various test pieces of metal bonded with the stuff every way I could think to and have come away a believer.


...just keep in mind I drive cars made outta frozen snot, too. :wink:

 

tony barnhill

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• Dec 16, 2009

• #13

Yep, Doc...same with me & FUSOR.

 

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bob67bgt

Jedi Knight

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• Dec 17, 2009

• #14

Over the years I have seen many things misused. I have also seen floors welded in by rookies that were probably less strong than using pop rivits. I do not doubt that done properly the panel epoxy is very strong or even stronger than welding. I would probably want my butt in a car that had the floors epoxyed in properly over a poor weld job. As long as i can properly weld the floors in thats the way i will do it. For me doing a structural job as close to the way the factory did it wins over new technology. I just wondor if the epoxy repair will be looked at as a DPO repair one day. Whatever way its done do it correctly. By all means if you can not weld have a professional do it or break out that tub of Elmers glue and give it a shot. Bob

 

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GaryBeu

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• Dec 17, 2009

• #15

Thanks for all the advice...we really appreciate the input. Almost ready to start cutting and we'll check out epoxy. Just hope there's enough decent metal around the edges to make this work! We'll let you know.

 

tony barnhill

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• Dec 17, 2009

• #16

I forgot 1 thing....before applying the epoxy....drill several holes in the new floor & the lip you left of the old floor (set the new floor in place & drill through it & the lip) for pop rivets.....after you apply the epoxy & set the floor in place, the pop rivets will pull it tight & hold it until the epoxy dries.

 

tony barnhill

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• Dec 17, 2009

• #17

Bob......I'm taking apart fiberglass panels on the Corvette to do some repairs from an old accident & to replace some broken panels.....to get the epoxy soft enough so I can run a putty knife through it to break the panels apart is taking a professional grade heat gun...I mean so hot it'll make an entire fiberglass panel too hot to touch....

That stuff is strong! Remember, a Corvette body is lots of fiberglass panels glued together....no screws/bolts/pop rivets/etc. Just epoxy!

 

DrEntropy

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• Dec 17, 2009

• #18

I used pop rivets every eight inches or so, pulled everything into place VERY well. Some may argue that is introducing weak spots but it IS the way UH-1's were assembled... I've seen first-hand the abuse some of THOSE things have undergone so I kinda have some faith in the methodology.

I also left about an inch of the vertical lip on the pan, cleaned both it and the mating surface on the body and used the "glue" there too. Those pans are POTTED in place.

 

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Britishautobody

Jedi Hopeful

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• Dec 18, 2009

• #19

Hi guys, I am new to this fourm >
I remember in my earlier rookie days working for a guy and we installed a complete Chevrolet conversion van roof skin with a Liquid nails epoxy or something similar. Tough stuff and expensive if I recall ,it sure saved us time with zero welding ,I am a believer.
That brings to mind another product I probably wouldn't use in my trade but maybe there is a place for it? I moved my shop to my new home location this past Oct. Installed a fire system system in the booth. They needed to cut 2 access holes in the side panels, so I made cover plates out of gal steel. I caulked them with fire rated Fire caulking. I didn't think much about this stuff until I tried to pick at it a week later.I discovered I will have to hammer and chisel this stuff out later to gain access. Amazing adhesion to non prepped Galv steel. Even on concrete to fill cracks I am sold!!!

 

DrEntropy

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• Dec 18, 2009

• #20

Welcome to th' fray!

I've no experience with "Fire caulking". Very interesting that it adheres to galvanized material like that.

This SEM panel bonding stuff worked surprisingly well on steel and aluminum, figured it'd NOT stick so well to galvanizing. I may try that to see!