How to improve Park Brake Performance with Dr Diff Rear Wheel Disc Conversion?

Cal Tonsley said
Hi All
I’ve converted my Aus Valiant Hardtop (69 Dart) with 8 3/4” to rear wheel discs using the Dr Diff Mopar 10.7" Rear Disc Brake Kit
While braking performance has been track tested and is very good, I need to improve the effectiveness of the park brake in order to pass my roadworthy inspection. I find that the park brake holds the vehicle somewhat satisfactorily with the rear of the vehicle facing downhill but it is hard pressed holding the vehicle on an incline when the front of the vehicle is facing downhill. I have done a fair bit of searching regarding adjustment methods and optimisation but am still looking for some advice. Apart from cable adjustment, the only other tip I found for these Cobra calipers is to apply and release the handbrake 20-25 times and then apply the foot brake. I have done this once but found little in the way of improvement. I have adjusted the cable to where there is a little drag in the released position and I can only pull the park brake out 3-4 clicks. With the foot brakes applied I can pull out the park brake another 4-5 clicks but still the performance of the brake is marginal on anything but a level road.
Can anyone please advise any other tips regarding adjustment of the park brake using the Dr Diff kit in order to maximize park brake holding power?

Thanks in advance!

View attachment 1716342328

View attachment 1716342329

I run DoctorDiff's 11.7" rear disk kit on my Duster and haven't had any issues with the parking brake holding the car on a hill in either direction, my driveway is fairly steep so it has definitely been parked on a hill.

How many miles are on the rotors and pads at this point? Is the picture of the rotor you posted the current condition or just a picture from when you first installed them?

I tested my car and found the number of "clicks" pretty hard to count accurately, can you take a picture of the lever with the park brake fully applied? Or maybe count the number of ridges visible on the park brake lever when it's fully applied?