im assuming you mean the pedal is going to the floor??
for starters, try bleeding the brakes, bleed the RR, LR, RF, LF calipers in that order.
if the pedal still goes to the floor, check the fluid level in the reservoir, and check all the brake lines and connections for leaks, if you dont find a leak it's probably the master cylinder.
also, double check the vacuum line going from the upper intake manifold to the brake booster. if it is cracked or loose it will cause the brakes to feel like they are slipping.
__________________ MAC Fenderwell CAI, MAC Catback 2.5" duals, MotoBlue 42%UDP's, Performance Distributors S/D coil & Taylor 8mm's, Diablosport Predator tuned, Steeda Tri-Ax, Spec Stage1 Clutch, Spec Aluminum Flywheel, FRPP Aluminum Driveshaft, Steeda Clutch Quadrant, Steeda Firewall Adjuster, 3.73's & FRPP T-lock, Zex 75 wet shot w/single outlet purge.
/ Flat Rate Hyundai Technician  / | 
Braking Problem 
