Rear Brakes Lock up above 80 degrees

[nevadacobra]

I just finished my MKIV Roadster and I noticed that in the morning (50F) when the car is on jack stands, I can spin all the wheels easily. However, when I come home and the ambient temperature is around (80F) the rear brakes are locked. Yesterday I took it on a test drive and I could feel the back brakes grabbing. I hurried home and the rears were smoking by the time I got in the garage. They stayed locked until this morning when the car rolls freely in the garage?? My mechanic friend suggested that I pump the brakes multiple times to see if they were building pressure and not releasing. I pumped the brakes over 20 times and the car rolled freely. However, when I get home tonight I bet the brakes are will be tight and the car will not roll. Any suggestions on troubleshooting the problem.

[Mr B oldschool]

did not see any help will assume rear disc put on jack stands let set as described if they lock up both rear brakes only crack the bleeder at right rear if they turn after this let sit again recheck if locked up crack left rear bleeder if free up let sit again if locked again brake steel brake line to T where where rear brakes tie in if they turn free this means rear flex hoses are ok let sit again if locked go to master cyl brake the line there too rear brakes if they free up ck the rod ajustment are balance bar if too tight fluid expansion will apply brakes that also would cause over heating and lockup after driving it's a starting point