Reservoirs

Reservoirs: the fluid tank that keeps your brake system topped and sealed

Brake reservoirs hold the hydraulic fluid your master cylinder draws from, keeping the system full as your pads wear and the caliper pistons travel further. The cap and seal keep moisture and grit out, which matters because brake fluid absorbs water over time. In the aftermarket world this category covers three real jobs: standalone billet reservoir kits that feed a remote or custom master cylinder, and cosmetic reservoir covers that dress up or protect the factory tank on the engine bay side. If your build has relocated or upgraded the master cylinder, a matched reservoir is part of getting the plumbing right.

What ThreePiece stocks

There are 11 products in this category right now, from 3 brands: Wilwood (7 in the sample), Perrin Performance (2), and Wehrli (2). Current pricing runs from $25 to $203 for what is in stock, which is a live range and not a fixed quote. Wilwood covers the functional side with billet aluminum kits such as the Billet Reservoir Kit 4 oz and the bracket version, the Billet Reservoir Kit 4 oz w/ Bracket. Perrin and Wehrli lean toward covers and dress-up pieces.

How to choose

Decide first whether you need a working reservoir or a cover for the factory one. A billet kit like the Wilwood units is the part you plumb in when you are running a remote or aftermarket master cylinder and need a defined fluid volume and mounting point; the bracket version saves you fabricating a mount. If your factory reservoir works fine and you just want a cleaner engine bay or some heat protection, the cover route is cheaper. Perrin offers both a soft Brake Reservoir Cozy and a hard Subaru Brake Reservoir Cover in red. Wehrli's covers are the higher-priced end of the range, including the Master Cylinder Reservoir Cover in Bengal Red and the WCFab Red cover. Covers are fitment-specific, so match the year and platform before buying.

Fitment coverage

Fitment data is attached to 3 of these products, spanning model years 1992 to 2023, with Subaru appearing directly in the product names. The covers are made for specific applications rather than universal, while the Wilwood billet kits are the more adaptable option for a custom setup. Because coverage here is a small sample, confirm your application before ordering.

What else you need with it

A reservoir is one piece of a hydraulic job. Pair a billet kit with the right master cylinder and fresh brake lines, and check your hardware while you have the system open. If you are refreshing the whole corner, look at brake pads, brake rotors and brake calipers, or start with a complete brake upgrade kit from the main Brakes section.

Fitment help and ordering

All orders ship free, and Affirm and Katapult financing is available at checkout. If you are unsure whether a cover fits your car or which reservoir suits your master cylinder, call our fitment line at 813-535-5801.

Reservoirs: the fluid tank that keeps your brake system topped and sealed

Brake reservoirs hold the hydraulic fluid your master cylinder draws from, keeping the system full as your pads wear and the caliper pistons travel further. The cap and seal keep moisture and grit out, which matters because brake fluid absorbs water over time. In the aftermarket world this category covers three real jobs: standalone billet reservoir kits that feed a remote or custom master cylinder, and cosmetic reservoir covers that dress up or protect the factory tank on the engine bay side. If your build has relocated or upgraded the master cylinder, a matched reservoir is part of getting the plumbing right.

What ThreePiece stocks

There are 11 products in this category right now, from 3 brands: Wilwood (7 in the sample), Perrin Performance (2), and Wehrli (2). Current pricing runs from $25 to $203 for what is in stock, which is a live range and not a fixed quote. Wilwood covers the functional side with billet aluminum kits such as the Billet Reservoir Kit 4 oz and the bracket version, the Billet Reservoir Kit 4 oz w/ Bracket. Perrin and Wehrli lean toward covers and dress-up pieces.

How to choose

Decide first whether you need a working reservoir or a cover for the factory one. A billet kit like the Wilwood units is the part you plumb in when you are running a remote or aftermarket master cylinder and need a defined fluid volume and mounting point; the bracket version saves you fabricating a mount. If your factory reservoir works fine and you just want a cleaner engine bay or some heat protection, the cover route is cheaper. Perrin offers both a soft Brake Reservoir Cozy and a hard Subaru Brake Reservoir Cover in red. Wehrli's covers are the higher-priced end of the range, including the Master Cylinder Reservoir Cover in Bengal Red and the WCFab Red cover. Covers are fitment-specific, so match the year and platform before buying.

Fitment coverage

Fitment data is attached to 3 of these products, spanning model years 1992 to 2023, with Subaru appearing directly in the product names. The covers are made for specific applications rather than universal, while the Wilwood billet kits are the more adaptable option for a custom setup. Because coverage here is a small sample, confirm your application before ordering.

What else you need with it

A reservoir is one piece of a hydraulic job. Pair a billet kit with the right master cylinder and fresh brake lines, and check your hardware while you have the system open. If you are refreshing the whole corner, look at brake pads, brake rotors and brake calipers, or start with a complete brake upgrade kit from the main Brakes section.

Fitment help and ordering

All orders ship free, and Affirm and Katapult financing is available at checkout. If you are unsure whether a cover fits your car or which reservoir suits your master cylinder, call our fitment line at 813-535-5801.