Master brake cylinder

The brake master cylinder is a hydraulic part that turns the force of your foot on the pedal into hydraulic pressure. That pressure pushes brake fluid through the lines to the calipers and wheel cylinders, bringing the car to a safe stop. It sits on the bulkhead behind the engine, right where the brake pedal meets the bonnet line, usually with the fluid reservoir on top.When its internal seals wear, pressure leaks past them inside the cylinder, and the brakes start behaving in ways you can feel. Because this is the heart of the braking system, a failing one is genuinely dangerous, not a fault to nurse along. If the pedal slowly sinks to the floor under steady foot pressure, the master cylinder is failing internally and the car should not be driven until it's fixed. The warning signs to watch for:

• A pedal that sinks while you hold it: The clearest sign, as fluid leaks past the worn internal seals.
• A spongy or soft pedal: Stopping takes more travel and the pedal lacks its firm feel.
• Braking that fades in traffic: The pedal slowly drops the longer you sit holding it at lights.
• The brake warning light on: Often paired with a dropping fluid level.
• Fluid pooling at the bulkhead: A leak from the rear of the cylinder where it meets the booster.
• Uneven or weak braking: One circuit failing leaves the car pulling or stopping poorly.

A used or aftermarket brake master cylinder undercuts a dealer one by a wide margin, but the listings are scattered over a lot of separate sites. Parthunt24 draws used brake master cylinder listings together from marketplaces like Ovoko, ProxyParts, eBay, and TotalParts, putting 398 options side by side on price, condition, and fitment before you choose a seller.

Getting the right cylinder comes down to a few precise details, because the braking system won't tolerate a near-enough match. The bore diameter has to be exact, since it sets how much pressure your pedal generates, and an ABS car needs a different cylinder from a non-ABS one.Match the OEM number first, then check the number of brake circuits, the port layout, and the reservoir type, all of which line up with what you're removing.Enter your make and model on Parthunt24 and the results drop to cylinders that match your car. Each listing leads through to the marketplace selling it, where the seller's full description and the checkout are waiting.

• Vehicle make, model, and year: Brake systems differ even between model variants.
• OEM part number: The most reliable compatibility reference.
• Brake system type: ABS and non-ABS systems require different master cylinders.
• Number of brake circuits: Single- or dual-circuit systems must match exactly.
• Bore diameter: Must match the vehicle’s braking-force requirements.
• Brake fluid compatibility: Check whether the system requires DOT 3, DOT 4, or DOT 5.1 fluid.
• Reservoir type: Confirm whether the brake fluid reservoir is integrated or remote.
• Port configuration: The brake-line connection layout must match exactly.
• Transmission type: Some automatic and manual variants use different braking setups.
• Mounting points: The bolt pattern and firewall fitment must align correctly.

On the seller's page, bear in mind a master cylinder's wear is hidden inside, so what the seller says about it counts for more than the picture. The internal seals decide whether the cylinder is any good and can't be seen, so a note confirming it held pressure on the donor car is the detail that matters most.

• Photos: The cylinder body, the ports, the reservoir mount, and the pushrod end.
• Seller reputation: Their score, recent reviews, and length of trading history.
• Compatibility: OEM number and bore size matched to your car.
• Included components: Bare cylinder, or with reservoir, seals, and fittings?
• Condition: Used, tested, or reconditioned? Ask about fluid leaks and pitting.
• Testing: Confirmation that it held firm pressure with no internal bypass before removal.
• Warranty and returns: A clear policy, which matters a lot in terms of the safety aspect.
• Shipping: Ports are capped and padded so dirt and damage stay out.
• Documentation: The car it came off and evidence of a clean removal.

If the seller's notes on pressure and condition hold up, place the order on their marketplace.

What you pay for a brake master cylinder turns on the car, the brand, and whether ABS is built in. A used cylinder for a common car runs around €25-€70, an OEM or ABS-integrated unit sits at €70-€180, and cylinders for premium or performance models can climb past €250.Brake master cylinder prices on Parthunt24 start from 5.00. Here's what sets one brake master cylinder price above another:

• ABS integration: Cylinders built into an ABS system cost more than simple non-ABS ones.
• Brand: Known braking brands sit above unbranded aftermarket units.
• Reservoir included: A cylinder sold with its reservoir saves a separate purchase.
• Model rarity: Common cars stay cheap; rare or premium models cost more.
• Condition: A tested, leak-free cylinder takes the higher price.

A quick price sort on Parthunt24 shows which seller has the cheapest brake master cylinder for your car.

The master cylinder is one link in a sealed hydraulic chain, so replacing it is the right time to check what it joins onto. Stale fluid and worn parts further down the line will drag a fresh cylinder's performance down, and the system needs bleeding regardless, so look these over while you're in there. Browse these on Parthunt24:

• Brake fluid reservoir: Cracked or stained reservoirs are worth renewing with the cylinder.
• Brake booster: Sits right behind the cylinder and shares its workload.
• Brake lines: Corroded lines often show up once the cylinder is off.
• Brake pads: Worth refreshing while the system is open and being bled.
• Brake pedal: Worn pivots affect how the pushrod meets the cylinder.
• Brake fluid: Always bleed through fresh fluid to the correct DOT spec after fitting.
• Brake calipers: Seized calipers put uneven demand on the new cylinder.

Get a brake master cylinder wrong and you've a safety part to send back and a job to start over, which is reason enough to compare carefully up front. Parthunt24 brings the major used-parts marketplaces together on one page, showing the condition, the bore and ABS detail, and the price for every brake master cylinder in the results, across mainstream and premium cars in Europe.Weigh every seller's cylinder in one view and the best value one stands out. Compare prices, find the best deal, and buy a brake master cylinder for your car today on Parthunt24.