Rather than reply on this old topic : http://www.zukiworld.com/forum/index.php?topic=15367.0

I prefer start a new one.

I've made some verification today on my Vitara brakes.

All is working well.
Calipers move on slider
Pistons are not jammed
Pads and shoes are almost new

Too, I have bleedded the system and a lot of oil has been replaced during this bleeding.

So, my Vitara is still braking very bad.

And after only 3 hard ( ) braking (45mph to 0), the pedal becomes very spongy and brakes are fading a lot.

I suspect front brake pads who are being replaced when I bought the truck.

I suppose they has not installed the best.

I don't know if I must just change front pads for better ones (Hawk, for exemple) or try to find if it's possible to install GV/XL7 bigger brake.   

Any suggestion?

my 04 vitara stops just fine I dont see any reason to change to GV/XL7 brakes personally i would have changed pads first then tried other stuff I've had pads that never would work great usually you get what you pay for also if you change to GV/XL7 brakes don't they all have ABS
I will keep my brakes just for the fact that I can use 15" wheels(cheaper,more to choose from, and lower ply rating)

my 04 vitara stops just fine I dont see any reason to change to GV/XL7 brakes personally i would have changed pads first then tried other stuff I've had pads that never would work great usually you get what you pay for also if you change to GV/XL7 brakes don't they all have ABS
I will keep my brakes just for the fact that I can use 15" wheels(cheaper,more to choose from, and lower ply rating)

Thanks for your advice! 

Finally, I've just ordered Hawk LTS pads with Raybestos disks.

LTS pads are supposed to be designed for light truck (Pickup, van and SUV) and  have better heat resistance.

http://www.hawkperformance.com/truck/lts.php

But I will have them only in 2 week.