Reinforcing Seat Frame

[davery]

My drivers seat has the familiar gangsta lean. It appears the passenger and drivers seat back frames are almost the same. It looks like the side with one bolt has a nut welded that could be removed and welded on the other side. There are two threaded holes on both sides of each frame. If I could find an unbent seat back (apparently a driver or pass), can someone suggest how to reinforce it so the lean doesn't happen again? And yes I already know not to raise the top from sitting in the car. Unfortunately, I learned this too late.

[DieselSpider]

VampyRepro in Orlando made his own with heavier C-Channel or Box Tubing from the local metal supply yard using the originals as a pattern. His seat frames were rusted and bent so he made more sturdy frames himself. He does welding/maintenance on metal roller coasters and amusement park rides so he is no stranger to this type of fabrication. The seats looked pretty solid and just like the originals to me.

Makes me sorry the previous owner tossed the original seats since the frames were rusted out as I would have liked to have had them as templates to do similar.

[klweimer]

On my first spider I had this problem and fixed it by taking the seats down to the frames and twisting the backs back into alignment (perhaps over twisted a little for good measure) and then reinforced the back by pop riveting aluminum straps diagonally from low on the outboard side of the back to high on the inboard side. As I recall, the strap was probably 1.5 - 2" wide maybe 1/8 - 3/16" thick. A bit hard to describe without pictures, but the idea was to put some torsional strength across the seat back.
Another thread that might be helpful: http://www.fiatspider.com/f15/viewtopic.php?t=7538
Kirk

[bobplyler]

Vick will do this. I don't know what they do,
http://www.vickauto.com/newstore/index. ... ts_id=2803

[bluespider262]

More tack welds. Many more. The frames on my 79 simply didn't have enough spot welds and the frame flexed.

Just putting a tack weld every inch or two on every seam, the seat is now probably 3-4x more solid.

Metal straps joining the seatback top to bottom, etc. are not needed IMHO if you add more welds to all the existing seams.

[davery]

My problem is I don't weld. So I was thinking of making the braces and taking to someone to weld. I've seen pics of a couple of reinforced seats. They seem to have either tubing or angle iron running vertical on the back side of the back frame. I was think of using angle iron and doing the same and then adding a horizontal brace about 2/3rds of the way up the frame between the two additional braces. Thanks for the input.

[klweimer]

I don't weld either (I know how, but no equipment or place to do so). I've done all kinds of sound repairs using lots of pop rivets. When done correctly, rivets will give you a zero movement joint like welding. Shear and tensile strength are not quite as good as a good weld, but at least as good or better than a weld that looks OK, but isn't sound.
Kirk

[davery]

I don't weld either (I know how, but no equipment or place to do so). I've done all kinds of sound repairs using lots of pop rivets. When done correctly, rivets will give you a zero movement joint like welding. Shear and tensile strength are not quite as good as a good weld, but at least as good or better than a weld that looks OK, but isn't sound.
Kirk

That's a good idea. I assume pop rivets would be stronger than a series of small nuts and bolts? I was able to find a good passenger seat. Now I just need to remove the welded nut from the inside of the frame and have it welded to the out side of the frame.

[klweimer]

Rivets will be much stronger and will swell in the clearance holes to give zero motion between pieces. Do a little research on pop rivets. I use either 1/8" or 3/16" diameter steel rivets. Get a decent hand tool or a basic air operated tool. I tend to get all my stuff from McMaster Carr. For example:
http://www.mcmaster.com/#6659a23/=138s0i7
Follow manufacture's recommendations for hole size and grip range. Use c-clamps to hold pieces together before riveting, just like you would if welding.
Kirk

[spider2081]

If you are riveting in stiffing members or for that matter almost anywhere you are adding metal and using rivets I would use a structural adhesive between the new and old metals. Its pricey but really adds lots of strength.

[davery]

If you are riveting in stiffing members or for that matter almost anywhere you are adding metal and using rivets I would use a structural adhesive between the new and old metals. Its pricey but really adds lots of strength.

That's a good idea. Maybe I use JB Weld to attach the braces and then come back with pop rivets.

[bluespider262]

If you are going to add vertical supports I would at least criss cross them.

The verticals don't flex so just strapping at the edges isn't really doing much.

Rivets should be okay if they fit the hole tightly. If not they Wont help nearly as much. This is ten minutes work for a welder.

[spider2081]

That's a good idea. Maybe I use JB Weld to attach the braces and then come back with pop rivets.

Not sure about JB weld, but I have used Dura-glass body filler on small pieces. the rivets need to be installed before the filler hardens. 3M makes products designed as structural adhesive. It has a longer work time.

[DieselSpider]

I tend to go old fashioned and get out my trusty old ball peen hammer to set solid rivits for structural repairs. Seat backs can too easily shear off pop rivits in even a minor fender bender.

[lglade]

+1 on DieselSpider's hand-formed rivets.

I work in aircraft manufacturing where we use NO welded joints of any kind on the airframe; this is due to the nearly un-measurable change in material properties when heated.

We therefore have hundreds of thousands of fasteners on an airplane, but we use almost no blind (e.g. 'pop') rivets because they will tend to loosen up over time and potentially fall out. We have some non-structural applications for them, but any rivet that goes through primary structure is a formed rivet (rivet gun & bucking bar).