Hey Guys! Haven’t posted in awhile but hope everyone’s doing well. I’ve got something to run by you. I’m swapping my buckets for an 03 Avalanche rear bench seat, it’s a tad wide but it works. I really like that the bottom lifts up and flips forward leaving access for lots of storage. I had a set of Silverado shoulder belts to install with it. Got them mounted but for some reason the inertia locks won’t release. I unbolted them they work fine but they will not release when mounted. What am I doing wrong?
Is your seat frame secure enough to withstand impact of 5 times your weight against the seatbelt? I think that's about what it would experience in a crash. I'm not an engineer, but that's a kinda rule of thumb. Others, feel free to correct. Bill B.
I'm with Bill, I'd attach to the floor (well-reinforced below) rather than the seat frame. I removed the integral seat belts from my Safari Van seat, since the structure which carried the load to the floor (the seat stanchions) was no longer being used. FWIW, you can purchase a "seatbelt mounting kit" from (in my case) Juliano's Hot Rod Parts.
As a forum member who has actually used his 3 point belt for the intended purpose (see https://talk.classicparts.com/threads/maybe-a-little-bondo.17800/#post-86513 ) I agree with Bill. Matter of fact, Bill helped me put the 3 point belts in my replacement '52 GMC. We used some 3" wide by many inches long 1/8" mild steel as "washers" to help distribute the load from the belt system to the cab. Make sure you don't attach the belts to the truck's frame because the cab could come detached from the frame and then use you as a cotter pin to keep the cab and frame together.
I did consider whether the seat frame was up to the task. I looked over the buckets I removed which had the seat belts built into the seat itself before I went this route. As an option I also had thought to use a bracket made from 1/4” angle iron that would attach to the floor. For reenforcement for the seat bolts I used some 1/4” spacers in this pic I had laying around. I do plan to switch out the floor bolts for grade 8.
