Allow me to introduce myself as the potential victim of the same problem
Wasted alot of time (and some money) to get my problem diagnosed. Kher i'll post a step by step method to troubleshoot your actual cause.
Step 1:
Cross analyse mechanics analysis. Start you car. Dont drive then shut the engine down after 10 seconds. Now press on brake paddle a couple of times. Dont need to hard press it. Just press release, press, release until you find the paddle getting hard. After that if you try to apply brakes, it would tend to be getting rock solid.
Now apply a mild pressure on brakes again, keep pressing and start the engine in neutral. If you feel the paddle depressing upto midway, BINGO, your servo is OK. No need to replace.
Step 2:
Since you mentioned that your paddle is going 3/4. There can be 02 causes. Cause 01 is more likely. As Mr. istafa111 said, go to mechanic and ask him to completely bleed your brakes. Remember, partial bleeding may not solve the problem. Buy 02 cans of SEIKEN brake oil. Go to the mechanic and whatever he says, just force him to do a complete system bleed. Totally remove the previous brake oil from all the lines of 04 wheels.
This will ensure 02 things, if there is air in the lines it will be removed. Secondly, your old brake oil that is contaminated with moisture shall be totally replaced. Some car manufacturer advise to completely bleed brake oil after 02-03 years (if you use the car or not)
Cause 02 is worn brake pads and leathers. Refer to step 3
Step 3:
Before encountering this recent problem, did you start to feel that your brakes are okay but the paddle goes about 1/2 depressed when brakes applied. If yes, i would recommend to replace the front Disk pads also (I would recommend the brand ASUKI. Cost you about Rs.600) Been using it and more satisfied than OEM ones. Yes people can disagree with me on this but.......an honest opinion
Step 4:
Although I am sure that your problem will be resolved by now. If you still believe that your problem is not solved, there is one final resort. Buy a set of Master Cylinder Seals from Reputed Suzuki parts shop. These are like a set of 04 - 05 rubber washers. Ask your mechanic to replace them in the MASTER Cylinder. Note: You'll have to re-bleed the whole lines again (my recommendation). However a skilled mechanic can replace them without much brake oil spill.
What I did was i performed all 04 steps before getting rid of the problem. For me it was master cylinder seals and contaminated brake oil.
Hope it helps. Do let us all know the results