The fifteen degrees is ideal but not set in stone as all cars have some different wear and characteristics.
Model a brake rod adjustment.
Place pin in clevis one at a time and adjust until pin snaps over brake arm.
The fifteen are after the slop is taken up turn the brake rod eye so the pin just slips in.
Pedal is more firm now and brakes much better.
Remove rod a 1853 that connects emergency brake lever to cross shaft center lever.
This video will show you how to do just that.
530 next replace the rod inserting it through hole b in center cross member and connecting the rod to the cross shaft center lever through upper hole c in lever.
Always be sure that all are loose as you do all four one at a time.
See that wheels revolve freely.
The brakes are controlled by rods that connect the front and rear wheels giving you the basic braking system.
Another good brake trick is to balance your brake rods to length.
Turn the adjusting wedge at each brake not the pull rod until the brake drags then back off the wedge 2 or 3 notches or just enough to allow the wheels to revolve without drag.
Turns out my push rod needed adjusted.
You can lock the rod clevice eye a bit out of plane with.
Make all adjustments with brakes cold.
Front at the wheels and back at the cross shaft.
The angle is set with the actuating rod or pills to take up slack.
My brake pedal was super soft after a brake booster replacement.
Jack up all four wheels.
Do the brake shoe to drum tightening before attaching the brake rod.
You will need to disconnect all service brake rods where the adjustment is made.
If the brakes are giving you a lot of trouble in your model a and when are they not it may be time to adjust them.
Release hand brake lever.