Brakes sticking, when hot

[Jeff & Debi <jplewis@cats.ucsc.edu>]

My brakes stick on, only when driving in stop and go type traffic, and
or hot weather. Car is 86 5KTQ. just bled and replaced fluid. Seems to
pass servo test per Benltey.Could it be the check valve on the bomb?
Should I rebuild, replace the servo?
Any btdt's?
Any help would be appreciated. do not want to go to a mechanic. The list
has helped me more than any mechanic ever has!

Thanks
Jeff Lewis
Aptos ca.
86 5KTQ 1.8 bar 100k mi.