Top anchor bolt nut rusted out

[Tomq]

I don't find any info in the archives on anyone that has tackled the rusted out anchor bolt/nut problem. I was thinking of cutting out the rail on the bottom, that is aluminum I think,replacing the steel plate with a captured nut, then resurfacing the SMC.A problem I see coming is to get the same tolerances regarding hole mounting placement and the fusion of the SMC, to the new construction. Aside from this rust, the cap is pretty good. All or any suggestions welcome,thanks for looking,Tomq

[truckster]

That seems like a tough one to deal with. It wouldn't look as nice, but what if you welded a capture nut on a steel strip (painted to prevent rust, of course) that could fit through a hole slightly larger than the nut, then tightened down the bolt and drilled and riveted the metal strip to the SMC?

I only say that because I'm ignorant of how strong a repair in the SMC might be. Perhaps someone with experience working with SMC can give better advice.

[1rippen6]

I'm guessing this is what you are talking about.

http://67-72chevytrucks.com/vboard/s...d.php?t=769164

[Tomq]

Thanks for the replies, after looking at your pics on the placement of these plates in the wall and how they are attached Mr 1rippen6,I was hoping to not have to be so severe in the re-construction of this anchor strip!I was wondering about opening up the end and sliding a new piece of material the full length of the side with nuts or fasteners of some sort attached to the new piece.When you took apart the top to cut out these parts in the pics #2 of that thread, was the end where the hatch is, have more aluminum up from the bottom of the anchor,or is it only a small piece on the length/corner to serve as a beginning of the form to attach the smc of the double side? Maybe making this too complicated to a simple fix.Thanks for looking Tomq

[pound41]

Thicker piece of metal that you drill and tap

[1rippen6]

I've replaced a couple before I just elongate the hole where the bolt goes through. I used a piece of wire fishing through the rivet hole and back through the bolt hole if that makes sense. I wasn't able to rescue the bad one it fell inside the top.

[cleszkie]

Why not use threaded nutserts in the existing holes of the steel backing plate? They get installed much like a rivet, but result in a new threaded hole. I've done this with good results. You can even select a nutsert with the same thread size and pitch as the stock bolts, but this may require that you drill a slightly larger hole in the existing backing plate. If you use steel nutserts (they come in steel and aluminum), you can even do a little tack weld between the installed nutsert and the backing plate as extra insurance against the nutsert wanting to spin.

[Tomq]

Mr 1rippen6 your suggestion seem proven,what size of flat bar did you poke thru the new slice you made?,and how did you finish up the larger hole? Mr Cleszkie I thought seriously of your plan,but some of these original steel back-plates are not to be found,unless you weigh the bucket of rust I have been getting out thru the rear bracket holes.Also thought of putting in some type of wing anchor,then putting nuts in the box under the lip,bot have waived this plan out because I am not sure if the remaining SMC would stand the pressure required to hold the top to the Jimmy box. Thanks for looking,Tomq

[1rippen6]

I used originals I cut from a different top I can measure one but all you have to do is make it larger than the two rivet holes. Now that I typed that I guess width would help I'll measure one tomorrow.

[1rippen6]

I know I'm late on this but just found them yesterday.

[Tomq]

Well,I used your method and made a small slot where the original fastner was,and then made new flat bars with a thread cut in them,elongated the hole in the fiberglass bottom rail,slid the new threaded flat bar [made a little longer to allow new holes for rivets to secure everything together] in the hole created in the cap.Everything seems good and solid again,just have to put a cover of fiber over the repair. Probably another 2 yrs before road driven!!!Thanks for looking,and advice.