BRAKE TROUBLESHOOTING - Disks
SYMPTOM CAUSE SOLUTION
LOSE YOUR PEDAL DURING HEAVY BRAKING CONDITIONS
Fluid boiling due to wet fluid or foot drag. Flush out entire system with fresh brake fluid. Install heat shields where necessary. 
Incorrect or faulty master cylinder. Repair or replace master cylinder.
Leak in caliper or hydraulic lines. Check for leaks in caliper and lines.
Pedal linkage failure. Check pedal assembly.
Excessive spindle deflection in corners. Check spindles for warping.
BRAKES ARE DRAGGING
Bad master cylinder. Switch or replace master cylinder.
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Rotors warped. Replace rotors.
Calipers not square to rotor. Re-align brackets or shim calipers.
Tapered brake pads. Replace pads, check caliper alignment to rotor.
M/C has internal residual pressure. Remove residual pressure valve.
CAR WILL NOT STOP
Glazed pads and/or rotors. Grind and/or sand glaze from rotors.
HAVE TO PUSH TOO HARD ON PEDAL
Not enough pedal ratio. Increase pedal ratio
Pedal mounted at bad angle. Master cylinder push rod should not be off more than 5° in any angle
Wrong pad material for your applications. Pads must match rotor operating temperature range. 
Frozen pistons in calipers. Rebuild calipers.
CALIPER LEAKS
Caliper seal old or dried out. Replace with new seals.
Nick or ding on piston or cut seal. Replace pistons and/or seals as necessary.
SPONGY PEDAL OR BOTTOMS OUT
Air in brake system. Re-bleed the system.
Calipers not bled with bleed screws straight up. Unbolt calipers and hold with bleed screws in the vertical position.
Faulty master cylinder. Replace master cylinder.
Calipers not mounted square to the rotor. Re-align brackets parallel to rotor, or shim caliper. 
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Calipers flex excessively. Check caliper bolts and brackets. 
Excessive spindle deflection in corners causing piston knock-back. Check spindles for warping or cracks.
OSCILLATION FEED BACK IN PEDAL
Excessive rotor run out. Shim between rotor and hub/hat.
Pad material buildup on rotors. Change pads, clean rotor face.
Calipers loose. Tighten caliper mounting bolts.
Rotor faces not parallel. Re-grind rotor faces, or replace rotors.
Cracked rotors. Replace rotors.
Excessive front bearing clearance. Check for proper bearing size, or tighten the spindle nut.
FRONT BRAKES LOCK TOO SOON
Possibly the wrong brake linings fitted at the rear of the vehicle, a wrongly adjusted or faulty brake proportioning valve, oily or worn-out rear brake linings, worn-out or damaged rear brake discs or drums, a defective rear wheel brake circuit. 
REAR BRAKES 
LOCK TOO SOON
Possibly the wrong brake pads or shoes fitted to the front or rear of the vehicle, a wrongly-adjusted or faulty brake proportioning valve, oily or worn-out front brake pads, worn-out or damaged front brake discs, defective front brake calipers. 
CAR SWERVES 
OUT OF LANE
DURING BRAKING
Due to problems on one side of the vehicle, e.g. the wrong brake pads, worn, oily or glazed brake pads, worn or damaged brake discs or drums, pistons that are rusty and can't move or that are difficult to move in the wheel cylinder or disc brakes. The issue is normally on the side opposite to where the vehicle swerves.