Master Cylinder Rebuild Kits

Has your brake lever gone soft, or is fluid seeping from the master cylinder on your motorcycle? With a rebuild kit, typically containing new seals and piston parts, you can rebuild the existing front or rear brake cylinder instead of replacing the whole unit.

How to choose the right kit

A rebuild kit is made for a specific master cylinder, so fitment is crucial. Check three things before you order:

• Position: front or rear brake, as the kits are different.
• Bore: e.g. 1/2, 11/16 or 3/4 inch, which must match your cylinder.
• Year and model: e.g. XL, FXR or FLT within a specific year range.

Many kits from Bikers Choice also list the original H-D part number they replace, so you can compare directly with your current part. In this category you will also find Performance Machine and OMIX.

Rebuild or new master cylinder

If the cylinder bore is scored or corroded, new seals typically cannot seal properly. In that case, one of our new master cylinders is often the better solution. Replace the brake fluid and bleed the system thoroughly after the rebuild. You can find related parts under master cylinders and brake boosters.

Frequently asked questions

How do I find the bore size of my master cylinder?

The bore is often stamped on the cylinder body or can be found via the original part number. Compare it with the product name, where the bore is stated as e.g. 1/2 or 11/16 inch. If in doubt, feel free to contact us with the number.

Can I rebuild the master cylinder myself?

You can if you have experience with brakes. The cylinder must be disassembled, cleaned and reassembled with the new parts, and the system must then be bled. Brakes are safety-critical, so if you are unsure, a workshop should do the job.

Why is the lever or pedal still soft after the rebuild?

This is often caused by air in the system, so bleed it again. A soft feel can also come from old or boiling brake fluid, hoses that expand, or a bore that is too worn for the new seals to seal.