Disc break issue in corolla 1974

[shahidkamal.1964]

I have a Corolla 1974. The drum breaks were replaced with disc breaks. Servo was installed recently. Wheels are getting jammed
Is there an expert in lahore.

[Hassan1991]

You know your problem already
You have upgraded front brakes without changing the distribution of brakes in front and rear.
Replace the proportional valve with the approx and your problem will be solve.

[arslan.v8]

KE20 comes with front discs rear drums, does your car have discs at the rear too?