This worked for me and I'm passing it on for you to try. I did some searching and didn't see where others had used this method.
Depress emergency brake pedal until all slack is gone and you feel resistance. Back up vehicle and get on the brakes with very firm pressure. Release emergency brake, pull forward a few feet and repeat the process until you get max benefit.
As I see it, with slack rear adjustment the master cylinder piston will stop from front brake pressure before the rear cylinders can engage shoes correctly to drum for self adjusting. By depressing the emergency brake you have the rear cylinders getting the required cylinder fluid action from master cylinder. A firm brake application is require for the adjusters.
Depress emergency brake pedal until all slack is gone and you feel resistance. Back up vehicle and get on the brakes with very firm pressure. Release emergency brake, pull forward a few feet and repeat the process until you get max benefit.
As I see it, with slack rear adjustment the master cylinder piston will stop from front brake pressure before the rear cylinders can engage shoes correctly to drum for self adjusting. By depressing the emergency brake you have the rear cylinders getting the required cylinder fluid action from master cylinder. A firm brake application is require for the adjusters.