Parking brakes that, when set, will prevent the car from rolling forward but not when rolling backward usually need a little more preload on the shoes
Umm... no. Parking brakes should keep a car from rolling forward or backward. Otherwise it's not a good parking brake. Never had a parking brake before that couldn't do both.
He didn't say that your parking brake should only work in one direction, he said if it isn't working when rolling backward it usually needs a little more preload.Ok I read it again. I don't see what I'm missing.
If he or anyone takes offense to the statement I said, I don't know what say.
The only one offended was probably me, the "Umm... no." was a surprising response to someone trying to help you.
Hope you get the issue resolved.