Inboard padOutboard pad

Condition 1: Excessive inboard pad wear

The inboard pad is located next to the caliper piston. When it wears faster than the outboard pad on the opposite side of the rotor it’s an indication the pad is maintaining pressure against the rotor surface at all times.

The following items can cause this problem:

Possibility #1 The square-cut O-ring seal has hardened, preventing the piston from retracting to the “at rest” position. SOLUTION: Rebuild the caliper with a new O-ring, dust seal, and slide bushings or replace with a factory rebuilt caliper. Replace the pads.

Possibility #2 The caliper guide pins are corroded, seized, have no lubricant or deteriorated lube. SOLUTION: Clean and lubricate caliper guide pins and bushings with a high temperature synthetic brake grease. Replace corroded pins.

Possibility #3 The brake pads are seized in the slides.SOLUTION: Replace pad slide hardware on both calipers and lubricate with proper lube. Replace the pads.

Possibility #4 The caliper piston has physical damage or is corroded.SOLUTION: Replace the caliper and pads.

Possibility #5 Residual pressure in the hydraulic system is preventing the caliper piston from retracting to its “at rest” position. SOLUTION: Check the condition of ABS hydraulic unit, master cylinder, metering and proportioning valves. Replace parts as necessary.

When disc brake friction materials wear prematurely or unevenly the wear pattern can guide you to the root cause. We’ll show you the four most common wear problems on single piston floating caliper braking systems. We’ll give you the most like causes and the best way to correct the problem. Always replace the pads and clean and lubricate the caliper pins and hardware. Clean the rotor. Then “bed” the new pads them by slowly stopping the vehicle from 30-mph. Allows 30-seconds for the pads to cool. Then repeat the procedure 29 more times.

Diagnosing Premature Brake Pad Wear

Inboard padOutboard pad

Condition 3: Pads are worn in a tapered or wedge pattern

A tapered brake pad indicates a binding condition that’s preventing the pad from applying evenly. The binding can be caused by caliper mounting hardware or a pad that’s seized in the slide. Check the following items:

Possibility #1 The brake pads were forced into the caliper slide area.SOLUTION: Double check the pad fitment. Remove the pads and check for corrosion on the ends of the pad backing plate. Check for debris wedged in the pad slide area. Correct the condition and replace the pads.

Possibility #2 One caliper guide pin is worn or seized or the rubber guide pin bushing has deteriorated. Either condition would cause the caliper to cock during application and apply uneven pressure to the pads. SOLUTION: Check the guide pins and rubber bushings for wear, corrosion, incorrect lube, or lack of lubrication. Replace cracked or deteriorated rubber bushings. Install new guide pins and lubricate with high temperature synthetic brake grease.

Inboard padOutboard pad

Condition 2: Excessive outboard pad wear

When the outboard inboard pad wears faster than the inboard pad the condition proves the caliper piston is releasing and the problem isn’t caused by an hydraulic issue. The following mechanical items can cause this problem:

Possibility #1 The caliper body isn’t releasing clamping pressure on outboard pad due to corroded or seized caliper guide pins.SOLUTION: Clean and lubricate caliper guide pins with high temperature synthetic brake grease. Replace corroded pins. Replace the pads.

Possibility #2 The outboard brake pad has seized in the slide.SOLUTION: Replace pad slide hardware on both calipers and lubricate with proper lube.

Condition 4: Pads are cracked, glazed, missing friction material, or exhibit edge lift from the backing plate.

This condition is a sign of thermal distress caused by improper installation, overuse of brakes, residual pressure in the hydraulic system, or improper adjustment or operation of the parking brake.

Possibility #1 Improper bedding procedure. Overzealous brake pedal application causes the friction material to overheat, glaze, or crack.SOLUTION: Check for proper caliper guide pin movement and pad slide operation. Replace pads. Perform 30-30-30 bedding procedure.

Possibility #2 Improper fitment of pads, rotor, or shims. SOLUTION: Double check fitment and replace if necessary.

Possibility #3Seized caliper guide pins or pad slides. SOLUTION: Check caliper guide pins and pad slides for corrosion and replace as necessary.

Possibility #4 Overzealous braking by driver. SOLUTION: Replace rotors and calipers if they show signs of overheating. Replace pads. Advise customer on proper vehicle and trailer load limits and proper braking technique when hauling heavy loads.

Possibility #5 Residual pressure in the hydraulic system is preventing the caliper piston from retracting to its “at rest” position. SOLUTION: Check the condition of ABS hydraulic unit, master cylinder, metering and proportioning valve. Replace parts as necessary.

Possibility #6 Improper fitment of pads, rotor, or shims. SOLUTION: Double check fitment and replace if necessary.

Possibility #7Parking brake is not adjusted properly (rear disc brakes), the cable is seized, or owner drove while parking brake was applied (rear disc brakes). SOLUTION: Check parking brake cable operation and adjustment. Adjust or replace parking brake components as needed. Replace brake pads.

Possibility #8Brake pads were defective or low quality SOLUTION: Replace with application specific brake pads.