How did I break my wheel cylinder link?

[Dan McCrea]

I have an 81 F150. I went to change the rear drum brake pads. When I pulled the drum there was a part that fell(?) into it. It's one of the pins (link) that pushes the pad out from the cylinder.

It is about 2 inches long, has a rectangle end to fit the notch in the brake shoe and a round (not tapered) end for the cylinder. Both ends are intact but the shaft burst or twisted and now looks like a drill bit. (It's still one piece) Nothing else appears damaged?? The drum surface is not scratched or gouged, all springs and other parts seem okay.

Does anyone know how and when something like that can occur? I have no idea if this could happen from the shoe and cylinder or if it fell out and then got damaged. Puzzled.

Dan

[Dan McCrea]

My buddy seems to have solved my mystery. His theory is the brakes were way out out of adjustment. When the brakes were applied the pin had no shoe to stop it and fell out. It lodged itself somewhere and the rim of the drum rode over it cutting the deep groove diagonally the length of the pin and twisting it a bit. Thus the drill bit look. The groove in the pin fits perfectly on the rim of the drum. The brake pads were soaking wet from fluid pumped by the cylinder. I'd like to say I didn't do the previous brake job but none of you would believe me.

:-)

[DeltaP]

Use the parking brake much?

[Dan McCrea]

I dont, but the previous owner may have. Will that alter the brake adjustment?

[DeltaP]

If the drums are worn past their limits and the shoes aren't concentric to the drums then when the shoes get way out of adjustment and the park brakes are applied the links get very loose between the cylinder pistons and the shoes. They're not supported by much and one or more of 'em can get "cocked" and pop out of position and fall out.

[DeltaP]

Weak return springs can help this scenario along too.

[Dan McCrea]

Thank you very much. The machine shop told me the drum in question was junk when I went to have it turned.