Check the bypass valve differential pressure control (models without ABS and EBD)
Defective control valve is subject to replacement without fail!
PERFORMANCE ORDER
Plug gages designed to measure the pressure to 100 kgf / cm 2, GTZ and the rear side of the valve-regulator.
Gently squeezing the brake pedal, determine the dependence of the pressure in the brake circuit of the rear wheels of the pressure GTZ. Compare result of measurement to a reference chart. A faulty regulator valve replace.