1967-72 door hinges

[Accelo]

I just finished rebuilding another set of 1967-72 door hinges.
There are several issues I had to deal with.
1. I used a drill to mark the hinge top halves with a small dimple. This way I always knew which side the pin should be driven in from. It also keeps me from making assembly errors.
2. The new pins were not straight.
a. Some had as much as .025 run-out. None, I inspected, had less than .005.
b. After removal, the old pin run-out was worse than the new pins.
c. Pin material and finish type varied. Black or plated seem to be the most common.
d. Outside diameters were close and varied less than .0005”.
e. All were 3/4" too long. Cutting to length, before insertion, seemed to work better.

3. Hinge ears would invariable get bent in the dissemble phase. This happened no mater how careful I was or how much heat I had to use to get the old hinge apart.
a. They were bent back into shape using a punch that matches the contour of the outside diameter of the ear. This kept me from flatting the bore from hammering on the OD. The pin is checked by inserting the pin through both sides and inspection where it impacts the other ear. This step is completed without the other half of the hinge installed.
4. The factory used nylon bushings. I have not found any aftermarket source for these bushings.
a. At lest 3 different styles of replacement bushing are available. See attached picture.
b. One is steel and the other two brass.
c. I prefer the longer brass bushings; your results may vary.
d. Always inspect the pin fit after installing the bushings.
e. Rotate the pin while installing as the pin and/or bore may not be straight.
I learn something every time I rebuild a set. First the quality of the parts varies a lot. Not only do the bushing vary but the straightness of each pin varied. Some manufactures had crappy bushing but straight pins.

I have included a picture of the three different styles of bushings. As you can see the manufactures have spent more time attempting to shave a penny off the cost of each unit. Having worked in manufacturing I can relate to the never-ending lengths they will go to. GM was the same, they are not getting off the hook. But I will stay current and just address the parts I have purchased.
The last bushing/ pin set was from eBay and sold by motorcitymusclecar (Iinline Tube) In the sales picture the bushing looked brass colored. They are not brass but coated steel of some type and they are magnetic. The picture was misleading in my opinion. These bushing are longer than stock nylon bushing and may be pressed in beyond what the stock bushing protected from corrosion. They went in with some difficulty. After they were installed getting the pin through both bushings was impossible. I galled the pin in my first attempt to install it. It came out hard and I ruined the new pin in the process. Galling would have been impossible if brass was used. Inline Tube did have the pins with the least run-out and may have been the better steel based on how the pins parted on the lathe.
Careful alignment after disassembly and careful part choices will make this a easier job. Seems a lot simpler than it is. Out of a 10-skill level it’s at least a 5. A large vise and a Torch are almost mandatory tools to complete this job.
Cheers.

[402Bowtie]

Any experience with NOS pins or bushings? Curious how they would compare...

[Richard]

I used GM NOS pins on my 72 doors. The pins were to long and had to be trimmed. Bushings were brass instead of the stock plastic. Only a couple of the stock bushings were partially intact. I chose to replace pins with doors and hinges on truck. One at a time, drove old pins out with an air hammer, tapped new bushings in place, slid new pins in and then drove them home with the air hammer. Was not to bad. A good long stroke air hammer helps a lot.

[Accelo]

Most the hinges I have been working with had not been functioning for years and would hardly move without a 12" Crescent on them. I will have to try the air hammer on the next pin. I have not as I was worried about penning the end over. I will give it a shot next time. I know the rapid hammering can have a much different affect than say smacking it with a 3 pounder.
I have even attempted to use a press on the pins. They are difficult to position and most required the press and heat to disassemble anyway. The last hinge set came from a truck that hadn't been on the road for 20 years.
Good news is the hinges are very well built, compared to the stamped steel of later years, and can be repaired easily enough.
Thanks for the feedback. Always appreciated.

[Richard]

Using a pointed tip on the air hammer smaller than the pin usually keeps from peening the end out. Another little thing I sometimes do is use a small piece of tube just larger than the pin to keep the bit from dancing off of pin. Thanks for the info on the pins.