I converted my fj40 to disk from a 1979 mini truck. The rear axle is also from a mini truck. All wheel cylinders and calipers are new. I used a booster/mstr cyl from a 1996 Tacoma. When the pedal is depressed it will not return to top without assistance. This is only a factor when the engine is running. Also, I get very little travel, is that normal? I had the same problem when I was using the orginal master cyl/booster. After I converted to disc is seems that the brakes lock up after only 1 inch of pedal depression. Ideas?