I fitted new genuine Volvo rear discs, pads and shoes along with the adjuster modification to mine, then adjusted only the cable (leave the adjusters for now) and let the shoes bed in for a couple of weeks (parking brake poor at this point) then loosen cable and tighten up adjusters and re-adjust the cable and the parking brake can easily hold on a 15° incline.
Easiest way to adjust the cable is to unbolt the passenger front seat (UK models) and lift it back a few inches to allow access to the cable taking care not to disturb the wire connections under the seat
