SpecRacer.com

That's a weird problem. I had never heard of there being different size calipers before. I can see why it took you so long to troubleshoot this one.

Had this happen years ago half way though race felt like anker was thrown out .Chased this for a couple of events before i found issue. change out the master . it worked for me.They appear to work fine.not sure what ws going on but your describing same exact symtoms.old master bench tested ok ,but i think fluid was not returning to master as it should

Karl, I had that issue several years ago when I changed out master cylinders. Turned out I didn't have enough "slack" in the master cylinder rods and several laps into my first session on the track, my brakes, front ones primarily, locked up, hence the anchor effect. Simple fix to give the fluid more room to expand.