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Floor repair


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Kevin, Charlie, thanks for replies!


I have not decided to use a booster.  But it is a possibility, I just have not decided yet. 

I will be the first to tell you, that stock 521 brakes work reasonably well, provided they are adjusted, and maintained properly.  But I am pretty sure we can agree a single reservoir master cylinder is not ideal, if you get a leak anywhere, you lose all hydraulic braking.  I might also do a disk brake upgrade to a 521.


I am just trying to do some planning ahead.

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Thanks again to all who replied with your solutions to brake modifications, and improvements to a 521.  Now, back to floor repair.

The first nine pictures are the final test fit of the new floor into the drivers side of the cab.  For these pictures, the cab is standing on the back.   It is not all that difficult to pick up the front end of the cab, and tip the cab on to it's back.   I used #10-32 screws, and nuts to hold the floor into place.  My thought is I can drill out the holes on one side, and use washers to hold the floor in place, with washers, and do the welding.  I will find out.  Once I have one spot welded, remove the screw next to it, and weld that hole. 




















When I set the cab back down on the garage floor, I use two 4x4 across the bottom of the cab  The 4x4's just sit in the pockets where the cab normally bolts to the 521 frame.    I also put a short piece of 4x4 on the bottom of the 4x4 cross beam, as a foot for the cab to sit on.





The 1/2 inch bolt is countersunk in to the short 4x4 foot.  This allows me to slide the cab around on the garage floor easily.







When the cab was up on it's back, I cleaned the paint and primer off the edges where I am going to weld the new floor in.





I set the cab back on the floor, and cleaned the top side of the metal edges where the welding the new floor piece is going to be.


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WillDatsun, you do some pretty good work, too.


I need to make a few smaller floor repair pieces.  This picture shows the floor test fitted and screwed in place, but  the wheel well piece of the cab had rust holes in the bottom, and was cut out.



These holes are up higher on the wheel well piece, under the clutch pedal.



These are pieces I made for the bottom of the wheel well panel.  The bottom piece was tough to make, it is hard to bend metal onto a compound curve.



This smaller piece will get worked some more, trimmed, and then welded to the new piece just below it, then welded into the cab.  These two pieces fit in between the new floor, and some braces on the cab.



This is the second cab, that has the front end sheet metal removed, but has a very nice floor.  I removed the brace, that I am holding in my hand, so I could check the fit of the two smaller wheel well pieces.  I also did a small amount of hammer forming the wheel well pieces on this cab.  The brace was removed with a spot weld saw.



I also sprayed this weld through primer on the new floor piece, and inside of the bare metal on the cab.








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The metal brake I got at Harbor Freight.  You can see it is very simple, and does not have built in clamps to hold the metal.  I need to get some clamps to hold the metal in the brake.  But after using a coupon in the newspaper, and timing a sale, I paid less than $48 dollars for it.


While on the subject of clamps, these are some panel clamps I made.   I did not like how the small piece of metal was fitting above the cab floor brace, this is a second piece of metal that was bent and welded to the bottom of the wheel well repair in previous pictures. 



Back side, with one more clamp.   It looks like I may need to cut out more of the old metal from the wheel well panel.



The panel clamp is very simple.  It is a brass pipe nipple, with a slot cut in one end.  The other parts are a bolt, and a nut that fits the bolt.  The head was cut off the bolt, and then a slot was cut into the end of the bolt.  After that, a piece of sheet metal was welded into the slot in the bolt.  Finally, a hole was drilled into the sheet metal.   Then a short piece of welding rod was cut, that fits the hole.



This is the clamp put together.


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WOW, you guys get really deep into this, I just use a board or some other piece of metal to brace one or the other side then make a tack weld, then do it again in another spot till it stays where I want it.

I guess I am not the patient type, when I start fitting panels, I just put them in position and tack it, and then stand back and see if it is right, if not, grind the tack off and re-position it and tack it again, repeat, I am good at grinding. :lol:

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More welding, and grinding, finding pinholes, and welding some more.   I used a bright light under the weld to find pinholes, and then weld them.  I should of cut higher up on the old metal, and had thicker metal to weld.  I was welding by using a series of small tack welds, but in some areas, just as soon as I started a weld, it blew through the old metal, where it has some rust damage, on the inside of the cab.



This is my welder settings.  I am using .030 wire, CO2/Argon, and the "Autoset" on the welder.



After welding I had some high spots, from heat distortion.  I have this big hammer, that I used to move some high spots down.



This is the face of the big hammer.  A nice round face, it works pretty good.  With a big hammer, you can easily tap lightly.  With a small hammer, it is hard to hit hard.



After working large high areas down, I used this flat dolly under the weld,



and this body hammer over the welded area.  Most of the weld was ground down, but not all the way, yet.BodyHammer_zps3963e3fb.jpg

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  • 2 weeks later...

This is a paint stripping disk I found at Home Depot for slightly less than $10.00.  I used it remove the plastic filler, and some of the rust off the roof of one of my 521 cabs.



The last remaining patch of filler.  Notice the vacuum hose, and brush in the background.   By running the vacuum as I am grinding the plastic filler, the mess is a lot less than it would be.



I will get back to floor repair soon.

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Hi Ratsun,

I have a '71 521 that has some holes in the floor. I have viewed all of the DIY jobs and they look cool and functional. Is there a SoCal shop doing the work? i just don't have time and dividing it with a '69 Roadster project. I'm in Ventura, Ca.



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A few days ago, I cut one of the 48 inch pieces of metal into two pieces, for passenger side floor sections.   I also am starting to figure out how to do some bends with the sheet metal brake I got just before Christmas, but first, I needed to bolt the brake down.  I did not want to bolt it to a bench, because i wanted to work on the bench.  I bolted the brake to two metal saw horses I have.



I picked up a piece of angle, and just used it to clamp the brake to the saw horses.



End view of brake bolted down.



OK, the brake bolted down, time to work on floor pieces.  This bend is below the front edge of the seat.  It is 90 degrees to the door sill, on the left side in this picture. 



This is the bend at the front of the floor pan.  The area under the clamps, in the brake is the up slope to the firewall.  This is actually the third bend I do.



The bend by the transmission tunnel is more complicated.  It is not really a bend, as it is a radius curve.  The metal did not really want to smoothly bend.  It is also not square to the other bends.  The radius also made it more difficult for me to locate the curve in the right spot.  I made this 2x4 buck, or pattern to get the angle right, and help locate the transmission tunnel curve.



This is a curve I cut, and sanded into the bottom of the  2x4 buck.  I clamp the sheet metal down between the buck, and bend the metal arounfd the curve, with the brake.



this is the transmission tunnel bend, or curve.



When you have one bend in a piece of sheet metal, you have to cut the corner, to allow a bend on the next edge of the metal.  In this case I did the firewall bend last.



I actually did the transmission tunnel bend three times before I liked it.  The first time I also welded the corner.  I had to cut the weld out,  and now,I have this large gap to fill.  This is the corner under the front of the seat, by the transmission tunnel.



This corner is the transmission tunnel to firewall corner.




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I did a test fit on the floor piece.

Door sill area.


Seat shelf.


The clamp was used to hold the metal on the transmission side where I wanted it to go.  Then the tab was tack welded, to hold the metal in place without the clamp.  Later I welded the gap in the corner, and removed the tab.


Transmission tunnel side.



Firewall side.



After some work in problem areas.  Picture takes from behind of seat shelf, looking forward.



This is the corner between the seat shelf and the transmission tunnel.



This view is looking straight down on the transmission tunnel.



This view is looking down on the firewall area.  This will have more metal welded to the top of this edge, go up higher on the firewall.



This is a temporary tack weld.  It is just there to hold the metal in position, for test fitting.


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More 521 floorpan work today.  If you look at the last picture, in the previous post, I needed to add more metal to the new right floor pan I am making, to go up toward the firewall.

This may look kind of like a piece of metal, but it is actually cardboard, with a very thin layer of aluminium on one side.  Before I took this picture, I just held it in place, and drew where the curve was for the wheel well.  Then I took a pair of scissors, and cut it out.  This was just a test fit to see if I needed to trim is some more.



I had already cut out this piece of metal.  This picture was also after I marked it with the pattern.



I laid the pattern on the metal, to mark the metal.



And then, my camera lens got stuck in the out position, and the camera quit working,


I cut the metal out of the sheet steel to match the pattern, and then bent the transmission tunnel side, in my sheet metal brake, to sort of match the curve on the floor pan.  It got welded to the floor pan, and a lot of grinding of welds, and rewelding places i did not like. 


I did a bit of internet research, and actually found a site that you can pay a little to "ask an expert"  I found some tips that might make a digital camera lens work again.  I got my camera working.


Back to the floor pan.

I did a little more weld clean up on this corner.



This is the small piece of metal going up to the firewall welded in place.



I also put the body mount dimple into the floor pan.



This is the bottom of the cab, and the floor fitted to the brace that goes under the floor.  Inside of brace, looking out.



Outside of brace, looking in.



This is the aft end of the floor pan, held to the cab with screws, and nuts.


I think the fit on this pan, in this cab is pretty good.


Last bit of work I did on floor pans was to cut the long piece of metal for the left side floor pans.



After I got the metal cut, I worked on my camera, and got it working.  I went out and took the pictures of the work I did complete, after my camera quit working.

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I am making the bends in a left side floor pan for a Datsun 521.  the door sill bend is already done, and the next bend I do is the one by the front of the seat.  It is 90 degrees to the door sill.  Depending on how far up on the seat shelf you have rust issues, you make measure where you want this bend to be.  I decided 2 1/2 inches from the edge of the metal.  I am going to bend this area about 45 degrees, so I need a 45 degree "V" cut out of the flange, to allow the bend.  I did that with a cutoff disk, and a die grinder.  Here I am measuring the location of the "V" cut.



The "V" notch was cut, and then I used a big Sharpie felt pen to mark the steel.  I used a carpenters square to locate the mark.



The marked line is used to locate the steel on the brake. 



Here I am just locating one side of the black mark directly over the hinge line on the brake.



Same as above picture, other side of metal.



Double checking with a ruler.



Double checking the other side.  This picture was taken closer than the above picture.  Both measurements are about 7/16.



Then the steel was clamped down.



And then the bend was bent.



About 45 degrees




Tomorrow, I an doing the bend, or curve alongside the transmission tunnel.  This is not a straight bend, and at the front of this bend, there is a funky hump on the floor, by the gas pedal.

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