Tap and Die

[DnvrJay71]

anyone ever redone the inserts for a doublewall hardtop? I've got a situation where a couple of the threads are stripped out.
a couple have bolts sheared off in them. I went and bought new bolts (5/16-18) but they don't fit the threads in the inserts.
How would you all suggest repairing it all so I can bolt it down properly?

[red71cheyenne]

If the fiberglass and metal are in good shape, you could just drill and retap to a little bigger size. You might check to see if someone didn't already do that to the ones that the 5/16 won't fit. They might be 3/8. Mine was so bad I had to just cut it all out and replace it with cut down 2X4's. Then I just used brass thread-serts to bolt to.

[71jimmy]

I had the same issue. To replace the "nut" which is in the shell, I used a 1 inch hole drill to drill the fiberglass on the inside of the shell, I spaced them so that I could do a couple of the bolt holes with only one hole in the shell. You'll notice, and I hope I recall this correctly because it's been a couple or more years, that under the shell and under the rubber weatherstrip, were it sits on the body, it has two rivets on either side of the "nut". Drill the rivets out carefully and then you can remove the nut part inside the shell. You'll find this "nut" is a piece of 3/8 inch metal by maybe 1.5 or two inches. Cut new metal stirps, drill appropriate hole and tap, reinsert into shell, rivet on, close fiberglass up.

Good Luck

[red71cheyenne]

Originally Posted by 71jimmy

I had the same issue. To replace the "nut" which is in the shell, I used a 1 inch hole drill to drill the fiberglass on the inside of the shell, I spaced them so that I could do a couple of the bolt holes with only one hole in the shell. You'll notice, and I hope I recall this correctly because it's been a couple or more years, that under the shell and under the rubber weatherstrip, were it sits on the body, it has two rivets on either side of the "nut". Drill the rivets out carefully and then you can remove the nut part inside the shell. You'll find this "nut" is a piece of 3/8 inch metal by maybe 1.5 or two inches. Cut new metal stirps, drill appropriate hole and tap, reinsert into shell, rivet on, close fiberglass up.

Good Luck

On mine it was a continuous solid strip with the nuts welded on. Thats why the whole thing had to go. Hope this method works though, much easier.

[BlazinC5]

When I got my Blazer, there were quite a few busted off bolts in my doubble wall top.. I managed to get them all out by drilling them out. What ya need is a centerpunch, hammer, full set of jobber drills, tap for the specific thread you have and what is called a center drill. It looks like a step drill but it is usually found in any machine shop supplier and possibbly napa may be able to get them to ya. I believe the bolts under the bedsides are 5/16-18. So a good center drill to use would be a #2 or #3. I believe i used a #3.


The good and the bad of a step drill.... Good:They are riggid and you can use your hand drill to direct the drill toward the center of your work by angling your drill in the direction you want to go, then slowly stand it up straigh when you feel your in the rite spot. It may take a few tries. But patience is key.. Bad: they are riggid, they will break real easy if you put them in a slight bind. Digging them out is a PITA. if it is possible..

To begin, I recomend trying this on some scrap 1/4-3/8 sheet metal. get some practice in by drawing some 5/16 diamiter circles on it. And by eyeballing it, use your center punch to put a ding in the middle of one of your circles. start your center drill in the center and if you find yourself off center just point the tip of that center drill where ya want to go. Once you feel you are about as center as it can be. plung the center drill straight into your work. checking frequently to make sure you stay center. Once you get about an 1/8" - 1/4" deap. switch over to a Jobber drill. with a #3 center drill start your Jobber drill at like 3/32". And drill all the way through. That is your pilot drilled hole. after that step up 2-3 or so sizes in your drill index. checking each time for if your hole is becoming off center.. if it is, use that same drill and run it freely in the hole putting preasure to the side that needs it. angling the drill can help to so long as your not to close to the edge.
Now when you accualy get ready to remove the broke off bolt. do as mentioned before, but when stepping up the drill, watch for signs of threads. that is where you stop on using larger sizes.. Take out your center puch and hammer again and tap on the heavy side of the bolt. Hopfully it will cave in on it's self and you can get it out with some needle nose pliers. if you don't get all of it out, just try running the tap through the threads you do have. don't force it to much though. Broken tap in the hole is VERY bad Ju-ju.. If you have some that are already stripped maybe going up one size on all of the bolts would be best. But this would be good practice and it will help keep the holes in the rite spot. And it's better than cutting the fiberglass.. When I did my top, it was on 2x4's lifted by nylon straps from the rafters with a flashlite for light. and yes I was going from the bottom up. I saved all my holes, so it can be done. Ohh ,, and WD-40 your drills and tap.. It helps alot..
Sorry this was so long...

[old man jimmy]

If all else fails, their's always heli coils.