Hi all my father inlaw has just bought a fiesta mk4 si. He took it for an mot and it failed on rear brakes,we've changed the shoes and bleed them,Now the one side now locks both with foot brake and handbrake but the drivers side doesn't any ideas?

 

bias valve may be faulty or maybe an airlock
contaminated drums could be to blame if the handbake doesn't do its job and need cleaning.