Reservoirs, Caps & Covers
About Reservoirs, Caps & Covers
The reservoir cap or cover closes the fluid chamber on a brake master cylinder and keeps dirt and moisture out of the brake fluid. Riders replace one that is cracked, lost or stripped, or fit a finished cover in chrome, black or a color to match the bike.
The listings here include front master cylinder covers for Harley-Davidson models, covers for Suzuki Boulevard and Intruder models, a billet rear brake cover for a Honda, and colored front and rear brake caps for KTM, Husqvarna and Gas Gas bikes. Surfaces range from smooth to finned or milled, in chrome and black. A cover is shaped to a particular master cylinder, so match the make, model and year in the title. Check front or rear, and keep any diaphragm or gasket the cover seals against so the reservoir stays sealed.
Brands in this category include Covingtons, Drag Specialties, Acerbis, Thrashin Supply Co. and Works Connection. The cover sits on a master cylinder, so see Brake Master Cylinders if the cylinder itself is leaking, and Rebuild Kits & Parts for seals. For the fluid path see Brake Lines, Hoses & Fittings. The whole group is Brakes & Brake Parts.
FAQs on brake reservoir caps and covers
What is the difference between a master cylinder cover and a cap?
Both close the fill opening of the reservoir. A cap is typically a small lid, while a cover is a larger, often decorative piece shaped to the master cylinder. Either one should seal the reservoir, so check which style your master cylinder uses.
Does a master cylinder cover need a gasket or diaphragm?
Most reservoirs seal with a rubber diaphragm or gasket under the cover. Reuse your original if it is in good condition, or use the one supplied. A cover that does not seal lets moisture and air into the fluid.
Will brake fluid damage paint and chrome?
Yes. Brake fluid can lift paint and mark plastics and some finishes. Wipe up any spill at once with a damp cloth, and keep the reservoir area covered while you work.
How do I check the brake fluid level safely?
Set the bike upright with the bars straight so the reservoir is level, clean the cover first so nothing falls in, then open it and compare against the level mark. Use only the DOT fluid named in your manual, and close it right away.
How do I know a cover will fit my master cylinder?
Covers are made for particular lever assemblies, listed by make, model and year, such as a Harley-Davidson year range. Compare the shape and the number of screws with your old cover, and check front or rear.
