Brake Pad Inspection and Replacement

How to tell when pads are done, and how to change them without ruining a caliper or a disc.

Brakes are the one system where a mistake has no gentle failure mode. This job is well within a competent home mechanic — but every step below that mentions torque, bleeding or a firm lever is not optional, and if you finish without a firm lever the bike does not move.

Tools

• Torx/hex drivers for caliper and pad pins
• Torque wrench
• Piston retraction tool or clamp
• Brake cleaner
• Measuring gauge or calliper
• Service manual

Knowing when

Pads have a minimum friction material thickness. That figure is in your service manual — measure against it rather than judging by eye. A pad that "looks like it has some left" can be below minimum.

Inspect both pads in each caliper. Uneven wear between the inner and outer pad usually means a sticking slide or piston, and fitting new pads without fixing that just wears the new ones the same way.

Look at the disc while you are there: scoring, a pronounced lip at the outer edge, or blueing all indicate the disc needs assessing too. Discs also have a minimum thickness.

A pulsing lever or pedal is usually a warped or unevenly worn disc, not a pad problem.

The job

Support the bike securely. You will be pulling on fasteners and you may have a wheel off the ground.

Before dismantling, note how everything is arranged — pad orientation, anti-rattle clips, shims and their order. Photograph it. Several of these parts fit more than one way and only one is correct.

Retract the pistons slowly. Pushing pistons back forces fluid up into the master cylinder reservoir, so check the reservoir level first and be ready for it to rise. Overflowing brake fluid strips paint immediately.

Clean the caliper and pad seats — but do not use a wire brush or abrasive on the piston face or the seal groove. Brake cleaner and a cloth.

Check the caliper slides and boots. A seized slide is a common reason for uneven pad wear, and fitting new pads to a seized slide wastes them.

Fit the new pads with any clips and shims in their original arrangement, and torque every fastener to the manual figure. Caliper mounting bolts are a safety-critical fastener — this is exactly where a torque wrench earns its cost.

Pump the lever or pedal until it comes firm BEFORE moving the bike. The first pull will go to the bar because the pistons are retracted. Riding off without pumping is how people discover they have no brakes at the end of the drive.

Bedding in

New pads need bedding in. Until they are, braking distance is longer than you expect — ride accordingly for the first few miles.

Follow the pad manufacturer's bedding procedure if they give one. The general approach is a series of moderate stops from moderate speed, allowing cooling between them, rather than one hard stop.

Avoid hard braking and avoid coming to a complete stop with hot brakes and holding the lever during bedding, which can deposit material unevenly on the disc.

Parts for this job

Check fitment for your own model and year before ordering — add your bike and we will flag what fits.

Other Harley how-to guides

This guide covers procedure and judgement. Torque figures, fluid capacities, gaps and tension settings are specific to your model and year and must come from the factory service manual for your motorcycle — we deliberately do not print numbers we cannot stand behind for your bike. Independent aftermarket retailer, not affiliated with Harley-Davidson, Inc.