[Sully1967]

My 1967 Sprint GT Veloce needs the following:

Driver side- Inner, Middle, Outer Sills. Front floorpan.
Passenger side- Middle and Outer Sills. Front Floorpan.

My replacement panels arrived from Classic Alfa (thanks guys!) and I’m trying understand the best way to install my floorpans and sills correctly. Two body shop guys who do collision insurance work (but NOT restoration work) have looked at my project and proposed I do the following:

Plan A (body shop guys plan)
-Cut and remove only as much floorpan out as you have to. Leave as much of the original pan as possible.
-Instead of drilling out the spot welds holding in the original floorpan across the transmission tunnel, leave a 3/4” ledge to weld my new floorpan to.
-Creating a ledge to weld to prevents me from disturbing the factory seam.
-Use seam sealer to seal the new seam that the ledge creates under the car.

Plan B
-Cut and remove the entire front section of the floorpan. Use as much of the new metal as possible.
-Leave a 3/4” ledge to weld to. This prevents disturbing the factory seam at the tunnel.

Plan C
-Cut and remove entire front floorpan.
-Drill all spot welds across inner sill and transmission tunnel.
-Spot weld the new floorpan to the new inner sill prior to installation.

What is the “best practice” way of carrying out these repairs? Thanks in advance.

 

[PSk]

It is all about the inner sill/chassis member? Are you replacing this or not?

If you are then your plan for replacing the floor pan alters completely as there will not be any need to leave any of the old floor plan attached to the old inner sill/chassis member as you will be removing the old inner sill/chassis member.
Pete

 

[Sully1967]

Thanks, Pete.

Driver side- Replacing Inner sill.
Passenger side- Keeping Inner sill.

You are correct about the union between new inner sill and new floorpan. I wasn't clear that my question applies to both driver and passenger sides.

-Transmission tunnel side- Drill welds or create a ledge?
-Use all of the new floorpan, or cut it down?

Thanks in advance.

 

[nunki]

Plan C. Especially because you bought the complete pans from Classic Alfa.

The time spend by your shops will be about the same whether they do a good quality patch or a complete pan replacement. Emphasis here on the "good quality"; anyone can tack weld some 20 gauge steel over rusted pans then apply a boat load of rubberized sound deadener and call it done.

bob

 

[Craig_m67]

Plan C

Drilling out the spot welds is quick and easy. Removing and refitting the floor panels as per factory is actually quicker than pfaffing about patching. Make sure you brace the car adequately when you remove the sills. The tunnel is paper thin so weld carefully.

Besides, anything else will always look dodgy, annoy you and absolutely lower any resale value later.

 

[tdskip]

If you are paying to have people do it for you it would seem it would be worth paying them to do it right, which the guys above have all pointed to as being C. Photo document it all and you'll get your money back on doing it right.

 

[Sully1967]

Thanks for everyone's feedback. The Alfa gods have spoken, I'm going with plan C. To answer a comment, I'm performing the repairs myself.

I spent the weekend running the spot weld drill and am close to removing the old front section of the floorpan. Where is the best place to mate the existing rear floorpan section with the new floorpan?

Option A- Use the entire new replacement panel. No trimming required.

Option B- Cut the new replacement panel short so as not to disturb the seat mounting points. Please refer to attached photo.

Should the butt weld between the old pan and new pan be in the same place as the transverse brace spot welds for the pan? Thanks in advance.

 

[Sketchl]

Ciao Scully 1967,

I opted for B as my front seat mounting metal was in good condition. In addition I cut just in front of the spot welds on the transverse cross member so it left a lip to rest the new floor pan which increased support and eliminated metal warp.

http://www.alfabb.com/bb/forums/car...icult-weld-floor-pans-72-gtv.html#post4701185

Good to see you're going about it the correct way.

Saluti
Sergio

 

[Sketchl]

Gear box support!

In addition, make sure you fit the rear gear box support when welding back the supports to the floor pan!

Saluti
Sergio

 

[shane1750]

Hi Sully
It looks like its too late but you should try to only replace the rusted portion.The floors only tend to rust on the outer sides.It will be very hard to replicate the spot welds on the longitudinal chassis rail and the gear box support. Find yourself a good welder who can butt weld.( I did, he is one of the best) The photos show gas butt welded repairs.

 

[Sketchl]

Ciao Shane,

That's a bit unfair as not everybody will have access to Achim V Hanke's skills! The guy is a dead set metal artisan and we're bloody lucky to have him close.....

If you want the best finish metal work in Sydney, I wouldn't go past Achim at Autocraft Restorations (no website as he's old school!) Tel: (+61) 0400 076553.

As for the floor pan repairs for a home job, plug welding complete floor pans in going to be a lot easier than gas welding patches!

Saluti
Sergio

 

[PSk]

As for the floor pan repairs for a home job, plug welds are going to be a lot easier than gas welding complete lengths of floor pans!

You should not weld the full length of the floor pans to the chassis rails anyway. The heat and resulting distortion would be considerable.

All you need to do is what is called seam weld, that means 1 inch on and 1 inch off. This is what they do to race and rally cars and will be perfect.

FACT: Less weld is better than too much weld! If you want cracks to appear keep over welding your car.
Pete

 

[shane1750]

As you can see in the first photo the floor was cut leaving a 10 mm lip
beside the chassis rail on which the new floor section was butt welded.
Therefore no need to stitch weld the chassis rail leaving everything
looking totally original.

 

[Craig_m67]

... and any rust that has been silently eating way at the sills, tunnel, chassis rails etc remains.

Why you wouldn't fix and improve this area when you're in there is beyond me. Removing the panel (floor, etc) correctly and inspecting, correcting and improving (painting!) the inner sills and chassis cross members is easy and ensures that your expensive repairs are good for another lifetime.

Rosette welds to mimic the original spot welds are easy to master (there's so many of them ) and look correct, unlike a patch.

Personally, I'm suspicious of anything that has been patched as it makes me think something has been missed or hidden due to time/money.

 

[shane1750]

... and any rust that has been silently eating way at the sills, tunnel, chassis rails etc remains.

Why you wouldn't fix and improve this area when you're in there is beyond me. Removing the panel (floor, etc) correctly and inspecting, correcting and improving (painting!) the inner sills and chassis cross members is easy and ensures that your expensive repairs are good for another lifetime.

Rosette welds to mimic the original spot welds are easy to master (there's so many of them ) and look correct, unlike a patch.

Personally, I'm suspicious of anything that has been patched as it makes me think something has been missed or hidden due to time/money.

Sorry Craig but to follow your line of thought to its logical conclusion would
mean replacing the entire body shell ! If there is no rust evident after 50 years I doubt it would start now.Why cut away good metal. The entire outer shell is made up of panels butt welded together.

 

[PSk]

Sorry Craig but to follow your line of thought to its logical conclusion would
mean replacing the entire body shell ! If there is no rust evident after 50 years I doubt it would start now.Why cut away good metal. The entire outer shell is made up of panels butt welded together.

While I can see where you are coming from, and on my car I have probably replaced more than many would have. And I have butt welded in many patches, I do not understand the not removing the whole floor panel and replacing the whole thing. IMO it is less work, especially because most of the time the inner/middle and outer sills need to be replaced anyway.

Anyway, great welding!
Pete

 

[Veep]

be sure to reinforce the body when cutting sills etc.. and check the fit of the doors including rubbers

 

[1750GT]

You've chosen the option that I decided to go with as well on my car. I posted a few photos of some of the steps I went through in the thread below....starting at post #120....that you might find of some use in your journey...

http://www.alfabb.com/bb/forums/gt-1963-1977/37021-afrench-blue-69-gtv-restoration-8.html#post547255