Honestly mate I'm unsure as from what I've seen you do in theory should work. The rear calipers have no trouble locking the rear brakes when I've done it before . I had the adjustable bias valve before the handbrake and didn't use the factory bias valve at all that's the only thing I can see different . Using the manual valve to adjust brake bias isn't an issue on rally or track cars as the car is stiffer and your not carrying loads or passengers which a factory valve will compensate for


Sent from under my Dok Dok