[Quentin Z]

No track, but had the same issue, rears locked up first. I have an older car and decided to replace the master cyl and add a proportioning valve at the same time. Interestingly, the replacement master cyl seemed to have different bore sizes front and rear, while the old one was nearly the same. Not sure if that's why, but the new cylinder works much better, and I never touched the proportioning valve, although its there if I need it.