Wilwood Pad Knockback

[67Rally]

I posted this question on PT as well, but haven't gotten much feedback yet.

I had been dealing with some pad knockback on the street over the past couple years. 12 bolt (c-clip) rear with 12.19" 4 piston Wilwood DynaPro's out back. (6 piston DynaPro's in the front, 7/8" Wilwood Dual MC, Wilwood Proportioning valve, manual brakes). All suspension, steering and brake items have less than 3,000 miles on them.

I swapped out the 12 bolt for a brand new Strange S60 with the tapered bearings, and kept the same brake setup. I have had 1,000-1,200 trouble free miles this year. Not a hint of knockback, until I ran my first autocross on Sunday, and it was back with a vengeance. First push on the brake pedal went most of the way to the floor, and then the next push I had perfect brakes, all day long. I had no faith in the brakes, and was too focused on the learning course to try left foot braking on my first outing.

I've done a ton of searching, but most threads didn't seem to have a resolution here or over there. I don't want to switch to a floater rear.

-I have seen mention of the D154 calipers, has anyone had good success with this option? Just adapting the D154's to my current rear brakes, or go with the full D154 rear parking brake kit?
-Some people recommend a residual valve. 2lbs? 10lbs? Is this a bandaid fix?
-Same with knockback springs? 5lbs? 10lbs? Better or worse than a residual valve?
-Some people recommended a larger bore MC, maybe a 1" bore?


Open to any and all REAL LIFE experiences. I really thought the tapered bearings had solved my issues, but they only fixed them on the street.