After last year's MOT test the tester said that the parking brake was out of balance and ideally needed adjustment. (I had recently replaced the parking brake shoes). This year to adjust it I followed the workshop manual procedure which said to tighten the adjusters until the wheels lock then back off the adjustment by 7 notches. I did this and had my first MOT fail for many years. The tester said the reading was just over 100 when it should have been 200.
I brought the car home and set about adjusting again. After 3 episodes of putting on axle stands, wheels off, adjust, wheels back on, take off axle stands and test drive, I was getting nowhere. The parking brake would not hold the car.
I adjusted the brakes again until the wheels were locked and the car struggled to move with the parking brake on. For attempt no. 5 I backed off the adjusters by only one tooth. I took the car for a retest and it passed with a reading of 200.
Hopefully my experience may help others.