BRAKE TROUBLESHOOTING

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.
	I
	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.
		I
	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.

TO CHECK YOUR BRAKE HYDRAULICS

Crawl underneath the car and use brake hose clamps to close all the flexible lines. Now you can check pedal travel. Locking them all off is to test the entire system. Please note that neither the servo nor the ABS system will operate without the engine running, though brakes should still operate with a dead engine and no ignition. It will merely take more pedal pressure to gain a "reasonable" braking AND will not be a true test running test if you have either (post June 1993 was the first installation of the servo boosted power brakes.). Pedal travel with all flexible hoses locked off/clamped should be as good a pedal pressure as you could ever get. With the cap of the brake fluid reservoir removed, look for either signs of bubbles of fluid flow within the reservoir indicating possible master cylinder seal failure allowing fluid or air to escape back past the seal into the reservoir.

After the all-hoses-clamped test, try releasing clamps and comparing pedal travel for each individual brake drum/disc set-up. It should be possible to detect if there might be an issue affecting one brake more than the others. As well, logic dictates that if brake shoes are not correctly adjusted it can require more pedal travel/fluid displacement to bring the shoes into contact with the drums to them create the braking effect

With your disc brakes, there is no adjustment to go wrong though on poorly maintained disc brakes you can have a situation where one pistons is not working while the other is. That will stop its side of its caliper pushing its piston out and the pad being unable to move. If this happens it is possible that the piston(s) on the other side of the same caliper operates normally when the pedal is pressed forcing the pad to contact the disc which in turn forces the disc to flex to the extent that it is forced over to make contact with the seized pad on the other side of the caliper. The effect of this feels not a lot different in relation to pedal pressure and the amount of spring normally associated with applying the brakes, however the brakes are less efficient when out on the road.

Mixing fluid types or the wrong type of fluid can cause all sorts of issues for seals, ABS etc. See the brake fluid section of this manual.