1974 620 Door Sag due to Cracking Broken Top Hinge

[Cardinal Grammeter]

My door started sagging about 3/4" at the latch - I could actually lift the door up at the latch to where it was supposed to be.

 

Turns out the top hinge was cracking in half with only about 1/4" of steel holding it together.  (Once that crack propagates through that 1/4", the hinge will be broken in half and there will be no top hinge support on the door - when you open the door, only the bottom hinge will support the door.)

 

It appears the reason it cracked was because that heavy wire spring that engages the detent wheel that keeps the door open so it doesn't slam back, the spring was wearing into the hinge body.  This wear was about 1/8" the result:  much greater force was required to lift the spring with the detent wheel when the door was opened - you really had to force the door open to get the spring up on the detent wheel.  This additional force created a large bending moment in the hinge body where the crack propagated.

PREVENTION:  Keep grease on the detent wheel and wire spring so it does not wear into the hinge body.

 

SOLUTION: 

1) Weld up the groove worn into the hinge body by the wire spring, or

2) With the spring up on the wheel, I put slid a piece of 12 ga copper wire into the wear groove and twisted it tight so it would stay in the groove.  This keeps the wire spring where it belongs so the force required to get it up on the detent wheel is small as original.  NOTE:  I don't know how long the copper wire will last, but if it gets worn through I think it would be possible to install again.