68/70Vette
Well-known member
Jerry's installed inserts into my bellhousing several weeks ago.
Latest problem. I bought Tom's Differentials CNC billet caliper brackets for my rear wheel spindle bearing housing assemblies. They are really a beautiful replacement for the stock cast iron brackets. I was bolting up a Stainless Steel Brake Corporation (SSBC) caliper to the bracket and as I was tightening up the bolt, it of course had the expected torque build up to tighten the bolt. Just when I almost got the bolt to the desired torque.....it started turning effortlessly. My heart sunk. Did I strip the threads? I backed the bolt out and inspected the caliper bracket. Being aluminum, it had steel inserts. The insert head had broken and snapped off. Actually I had also installed, but not fully torqued in the other caliper bolt. When I removed it I also had insert damage. I didn't want to repair this myself. If I buggered up the aluminum caliper bracket it'd mean removing the rear spindle axle..no way I wanted to do this. So I removed the two trailing arms (and strut rods, and spring attachments, and half axles) and took the assemblies to Jerry's. (The owner is Tom Grafton, Jerry passed away)
It turns out of the four inserts, two per side, only one had been properly installed by the machine shop that built the calipers for Tom. They had drilled and tapped the aluminum for the inserts, then screwed in the inserts, and then only used the final installation tool on one of the inserts. The installation tool flares the end of the insert to lock it into place. Three of my inserts had not had their bottom ends flared. When I was screwing in the 7/16X20 bolt, it ran up against the unflared end of the insert, jammed the insert, and then my turning the bolt caused the insert to begin screwing in deeper into the aluminum. Thankfully the stress broke the head of the insert instead of stripping the threads of the aluminum. If the insert is installed correctly, ahead of time you should be able to run a bolt all the way through it with finger pressure only. I called Tom and he checked his inventory and reported back that all the inserts in inventory are correctly installed. I think what happened is that during production someone was screwing in the inserts, finished one properly, then maybe when to lunch,etc, came back and forgot that three inserts had not been finished properly.
Latest problem. I bought Tom's Differentials CNC billet caliper brackets for my rear wheel spindle bearing housing assemblies. They are really a beautiful replacement for the stock cast iron brackets. I was bolting up a Stainless Steel Brake Corporation (SSBC) caliper to the bracket and as I was tightening up the bolt, it of course had the expected torque build up to tighten the bolt. Just when I almost got the bolt to the desired torque.....it started turning effortlessly. My heart sunk. Did I strip the threads? I backed the bolt out and inspected the caliper bracket. Being aluminum, it had steel inserts. The insert head had broken and snapped off. Actually I had also installed, but not fully torqued in the other caliper bolt. When I removed it I also had insert damage. I didn't want to repair this myself. If I buggered up the aluminum caliper bracket it'd mean removing the rear spindle axle..no way I wanted to do this. So I removed the two trailing arms (and strut rods, and spring attachments, and half axles) and took the assemblies to Jerry's. (The owner is Tom Grafton, Jerry passed away)
It turns out of the four inserts, two per side, only one had been properly installed by the machine shop that built the calipers for Tom. They had drilled and tapped the aluminum for the inserts, then screwed in the inserts, and then only used the final installation tool on one of the inserts. The installation tool flares the end of the insert to lock it into place. Three of my inserts had not had their bottom ends flared. When I was screwing in the 7/16X20 bolt, it ran up against the unflared end of the insert, jammed the insert, and then my turning the bolt caused the insert to begin screwing in deeper into the aluminum. Thankfully the stress broke the head of the insert instead of stripping the threads of the aluminum. If the insert is installed correctly, ahead of time you should be able to run a bolt all the way through it with finger pressure only. I called Tom and he checked his inventory and reported back that all the inserts in inventory are correctly installed. I think what happened is that during production someone was screwing in the inserts, finished one properly, then maybe when to lunch,etc, came back and forgot that three inserts had not been finished properly.
