oh, i forgot; my 2 cent:
firstly- identified your problem.hard to brake?can't brake?brake but not enough?nice braking but 2-3 times it'll be so hard? etc etc...
from here you can direct to root cause.
simple check, press pedal brake and see the pedal feedback.if it return to the original position, your servo is OK.
during braking, there must be a pressure at the end stoppage. means the fluid pressure enough..
try 4-5 times push the pedal.if its still the same force, your vacuum ok.
if all this symptom ok, means something not right at the mechanical stop section like hose, brake pad, ventilated disk, disk itself etc..etc..
maybe everybody can share their own experince of the brake problem.
mine was very hard to push the pedal after 3-4 times.after all the checking-try and error, found the vacuum one way valve at the vacuum hose not function.verified by Barhan - ex-lion suzuki mechanics-10 years doing auto works for suzuki and motorsport.