I've converted my 1976 FJ40 to 4 wheel disc brakes. The front brakes are original discs, the rear are a JTO kit with '85 Monte Carlo calipers. I installed a master cylinder for a FzJ80 to control everything with a Wilwood 260-12627 proportioning valve so I could tune it in. My issue is that I have the proportioning valve at the max "less brake" setting and my rears still lock up first. Do I have the wrong proportioning valve? Do I have something connected improperly? Any input is greatly appreciated.