Drum Brake break-in time
 

My 68 GTO has all drum, power brakes. Everything new, great feel at the pedal, everything properly installed.

I was wondering what the typical break-in time is for the shoes. Driving nothing but late model vehicles for the last 45 years I was a bit surprised at the lack of braking power when first moving the car around. Brakes "work", pedal is hard, booster seems to be working.

I built drum brakes for vintage racing motorcycles for years, arc'ing the shoes on a lathe for the fastest possible bed-in for the shoes, rebonding new aggressive compounds on old shoes, tuning the linkage etc. But I'm not an expert on the behavior of OEM type street brakes.

The car has only moved maybe a couple hundred yards, up and down my drive a few times, across the street and up and down that drive ... and they have gotten better.

Can I expect them to improve with actual on the road time an braking from more than 15 mph?

Thanks

the drums/pads need to be broken in or burnished. theres different procedures for this but most are basically doing some medium pedal force stops from about 35-40mph down to 5mph, not stopped. repeat at least 10 times with a minute or so cool down between. then do a few more at more aggressive braking from a little faster speed. you can google brake pad/shoe break in procedure for tips from many places, or call the brake shoe companies tech line to ask what they recommend.

take it out on a back road with minimal traffic & do a few of the slow downs and you should feel the brakes improve. heres just one link from summit, its for pads but the same process is done for shoes, you want to get a layer of brake shoe material on the drums. also want to turn used drums if they are within spec or if no signs of warping at least hit them with some 80 grit sand paper in a criss cross pattern.

https://help.summitracing.com/app/an...-and-rotors%3F

The post on the burnishing the new brakes is spot on.
If you have been driving 4-wheel discs for decades, then you will have to learn how much of a difference there is with "Mechanically Adjusted" Drum Brakes. Unless fully adjusted to the optimum position, drum brakes will have more pedal travel before engaging.
You can use a "Brake Spoon" to adjust the brakes at each wheel while the wheel is off the ground and free to travel when spinning by hand.
Make sure before using the brake spoon that the brakes have been properly bled.
The drum brakes can self-adjust each time you apply the brakes when backing up.
They will, however, never give you the same feel as four-wheel discs.