I think everyone will agree that hanging and adjusting doors on AD trucks is most easily accomplished using original, OEM hinges - and rebuilding them is the way to go. But when original hinges aren’t readily available or you need to work with existing aftermarket hinges, all bets are off. Things can get dicey real quick. This post focuses on at least two different aftermarket hinges and bending them to set door depth in the opening.
I humbly submit this as a compilation of information gleaned from various posts on the subject throughout this site (thanks!) and elsewhere using my own photos. I don’t claim to be an expert. This is based soley on personal experience and may, in fact, be old news to many of you. Opinions, techniques, and results may vary.
Hopefully, this will help someone struggling to get their doors to fit without them sticking in or out of the cab where they shouldn’t and have decent gaps — particularly when aftermarket hinges are used. It assumes any sheetmetal repairs have been done carefully and the pillars, hinge pockets, floor, cowl, and rockers are where they’re supposed to be. Doors from donor trucks may be a different size and shape!
The attached photos are referenced by letter.
With disclaimers out of the way, here’s my story...
The Truck A 1950 Chevy 3100 came to me with recent paint work and doors shells hung. The belt line was close but needed some tweaking. The leading edge of both doors rubbed the cowl when opening. The passenger side was the worst and I later found evidence suggesting the door was a donor. It was ‘tight’ in the opening without much gap. The upper hinge bolt heads interfered with the door, preventing it from closing all the way. The door was not flush with the cowl and needed to come out more but the hinges were maxed out.
Aftermarket Hinges Unnecessarily Hogged!I started pulling bolts that hold the hinges to the cab. What did I find under those large flat washers? Gaping holes way beyond any amount of vertical or horizontal movement possible. Someone had gone crazy with a die grinder. Bolt holes were hogged in every direction. The edges of the face plate, ground off in places. Even the sheet metal edge of the hinge pocket was trimmed away. The bolt heads were already crushing the washers into the void. I found the driver side hinges were also hogged out but not nearly as bad (photo A).
I could have spent the time welding up the holes but at this point we had no real reference for their size, shape, and location. So rather than try and repair this side I decided to order another set with hopes they might be better in other ways. I chose Dynacorn
Link to Dynacorn out of CA, a company we were familiar with. But like everything else, their reproduction parts are made overseas.
Differences, Pro, Cons When they arrived I found obvious visual differences between the generic repop hinges, that I think are sold by most vendors, and the ones made by Dynacorn (#1101C) (photo B).
The Dynacorn hinges appear more ‘finished’. The strap that goes into the door is slightly thicker and the rest of the hinge arm is ‘beefier’. The hinges pivot freely on the pin but not sloppily. The tin face plates are spot welded to the body of the hinges squarely.
The Generic hinges had tighter pins. Being slightly thinner material they would probably be easier to bend in a vise without heat.
The real test was whether the new hinges would bolt on and work without modifications. Was the bend and geometry of the hinge strap (arm) better or worse? In the end, all four would need a small bend to work correctly on this truck.
Adjustments and Bending Out of all door adjustments designed by GM into this hinge system, the 'door panel to cowl panel' (whether the door is flush with the cowl or not) is the trickiest and requires the most work.
The factory service manual only mentions bending the hinges to make this particular adjustment (photo C).
Are you old enough to remember film strips and projectors in class rooms back in the old days? I am. Brad Allen has posted frames from a vintage GM service training film strip called "Servicing Chevrolet Truck Cabs"
Link to Servicing Chevrolet Truck Cabs - Brad Allen that is a great reference for all things related to door adjustment. Frame #24 mentions "enlarging body hinge bolt holes or bending hinges" (photo D).
Personally, I think the hinge holes at the cowl can and should be left alone. They’re only slotted for vertical movement and any horizontal adjustment needed can be made by bending the strap. It’s just a little bit more work. What neither the manual or film strip tells you is where to bend, which direction, and how much. There are no suggestions on how to bend them.
I'll explain later how and why bending works the way it does. But the bottom line is: Bend the hinge strap in the opposite direction you need to move the door. Bend in to move the door out, and bend out to move the door in (photo E).
I'd suggest bending hinges only while off the truck. Using too much force while on the truck will likely bend the pillar and hinge pockets out of shape. And heat from a torch can damage surrounding paint, if that's a concern.
The generic hinge (being slightly lighter material) can be bent in vise with a pipe wrench (photos F & G).
I preferred heating them with a oxy/acetylene torch, in a vise, and grabbing the pin area with a large adjustable wrench (photos H & I).
(Continued)
