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<h2>What is a car brake master cylinder and what does it do?</h2>A car brake&nbsp;master cylinder plays an important role in the overall balance of the braking system. It is designed to provide equal pressure to all four wheels, which helps ensure that the vehicle stops in a straight line and doesn't pull to one side or the other. It is a hydraulic pump that converts the force applied to the brake pedal by the driver into hydraulic pressure.<h2>Brake master cylinder functions brake master cylinder functions</h2>The main function of the brake master cylinder is to convert the force applied on the brake pedal into hydraulic pressure that is used to actuate the brakes.When the brake pedal is depressed, it pushes a piston inside the master cylinder which in turn pressurizes the brake fluid in the cylinder. This pressure is then transmitted through the brake lines to the individual brake calipers or wheel cylinders, which then apply the brake pads or shoes to the rotors or drums respectively.<h2>Brake master cylinder diagram</h2>The master cylinder also has two fluid chambers, one for the front brakes and one for the rear brakes, to ensure that the brakes operate independently in case of a leak or failure. It also has a reservoir that holds extra brake fluid and allows for topping up the fluid as needed.<img src="https://media.cdn.a-premium.com/2022/item/image/e3c8d30a027b4060a0e2728defc4deb2.gif" alt="brake master cylinder diagram" width="1000" height="375" />Master brake cylinder failure symptomsA failing master brake cylinder can cause a range of symptoms that affect the braking performance of a vehicle. So if you notice the following signs, you may need a new master brake cylinder:<ul><li>Brake pedal goes to the floor: If the brake pedal goes all the way to the floor with little resistance, it may indicate a problem with the master brake cylinder. This can be caused by a loss of hydraulic pressure or a problem with the seals inside the master cylinder.</li><li>Brake pedal feels hard: On the other hand, a brake pedal that feels unusually hard or difficult to press down can also indicate a problem with the master brake cylinder. This can be caused by a restriction in the brake lines or a problem with the master cylinder's internal components.</li><li>Brakes are grabbing or dragging: A failing master brake cylinder can cause the brakes to grab or drag, even when the pedal is not pressed. This can result in reduced fuel economy and increased wear on the brake components.</li><li>Noisy brakes: A faulty master brake cylinder can cause the brakes to make unusual noises, such as squeaking, squealing, or grinding. This can indicate that the brake pads or rotors are worn, or that there is a problem with the brake calipers.</li><li>A brake warning light is on: A failing master brake cylinder can cause the brake warning light to come on. This can indicate a problem with the brake system, such as a leak or a loss of hydraulic pressure.</li></ul><h2>Brake master cylinder replacement steps</h2>Before replacing the brake master cylinder, you need to gather all the necessary tools and equipment. You will need a set of wrenches, pliers, a brake bleeding kit, a container to catch brake fluid, and a new brake master cylinder. After that, follow the steps:<ol><li>Disconnect the brake lines and wiring harness from the old master cylinder.</li><li>Remove the old master cylinder by unscrewing the bolts that secure it to the brake booster.</li><li>Install the new master cylinder onto the brake booster and tighten the bolts.</li><li>Reconnect the brake lines and wiring harness to the new master cylinder.</li><li>Use a brake bleeding kit to bleed the brake lines and remove any air bubbles from the system.</li><li>Test the brake pedal to ensure that it feels firm and responsive.</li><li>Adjust the pushrod that connects the brake booster to the master cylinder, if necessary.</li><li>Check the brake fluid level in the reservoir and top it off if necessary, and you&rsquo;re recommended to use the type of brake fluid recommended by the vehicle manufacturer.</li></ol>

Brake Master Cylinder

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Air Filter Box

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Mass Air Flow Sensors/Car MAF Sensors | A-Premium

Air Flow Sensor

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Air Intake Duct

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Air Intake Hose

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Air Intake Manifold Actuator Control Solenoid

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Air Intake Manifold Flap Adjuster

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Air Intake Manifold Runner Control Sensor

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Electric Vacuum Pump

Engine Air Duct Assembly

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Engine Air Filter

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Intake Manifold

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Intake Manifold Flap Actuator

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Intercooler

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Oxygen Sensor

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Pressure Sensor

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Throttle Body

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Throttle Position Sensor

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Turbocharger

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Turbocharger Oil Line

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Vacuum Pump

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Air Filters & Intake Systems

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Camshaft Adjuster

Camshaft Adjuster Cover

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Camshaft Timing Gear

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Camshafts

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Engine Valve Cover

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Harmonic Balancer

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Timing Belt Kit

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Timing Chain Kit

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Timing Cover

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Timing-Control Valve Solenoid

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Valve Lifters Tappet

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Cams, Timing & Valvetrain

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Belt Tensioner

Coolant Level Sensor

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Crankcase Breather Hose

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Crankcase Breather Valve

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Crankshaft Position Sensor

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Engine Oil Dipstick Tube

Engine Oil Filter

Engine Oil Pan Gasket

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Flywheel

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Oil Cooler

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Oil Cooler Line

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Oil Filter

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Oil Filter Housing

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Oil Level Sensor

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Oil Pan

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Oil Pump

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Oil Pump Pickup Tube

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Cranks, Pistons, Oil & Components

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Camshaft Position Sensor

Camshaft Position Sensor & Magnet Kit

Connector Plug

Distributor Cap

Engine Valve Covers & Ignition Coils Kits

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Glow Plug Relay Module

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Ignition Coil

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Ignition Coils & Spark Plugs Kits

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Ignition Distributor

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Ignition Starter Switch

Ignition Switch Actuator

Knock Detonation Sensor

Relay

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Spark Plug

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Spark Plug Wire

Electronic Control Modules, Ignition & Distributors

Engine Wiring Harness

Intake Manifold Repair Kit

Engine Components & Accessories

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Auxiliary Water Pump

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Expansion Tank

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Expansion Tank Mounting Plate

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Fuel Cooler

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Radiator

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Radiator Hose

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Radiator Support Assembly

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Temperature Sensor

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Turbo Hose

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Water Coolant Pipe

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Water Outlet

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Engine Cooling

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Engine Mount

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Engine Mounts

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Catalytic Converter

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EGR Valve

Emissions Fluid Pump

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Exhaust Fluid Heater

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Exhaust Gas Temperature Sensor

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Exhaust Manifold

Fuel Tank Breather Valve

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Fuel Vapor Leak Detection Pump

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Nitrogen Oxide Sensor

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Secondary Air Injection Check Valve

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Vapor Canister Vent Solenoid

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Exhaust & Emission Systems

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Fuel Filter

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Fuel Injection Control Module

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Fuel Injection Pressure Regulator

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Fuel Injector

Fuel Injector Kit

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Fuel Injector Module Wiring Harness

Fuel Line Kit

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Fuel Pump

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Fuel Sending Unit

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Fuel Tank Filler Neck Pipe

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Fuel Tank Strap

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Fuel Systems & Components

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The engine comprises many essential elements such as the lower cylinder block, upper cylinder head(s), and the cooling & lubricating systems. With A-Premium aftermarket engine components, you can expect that your engine deliver years of reliable performance. We offer a diverse selection of engine components from air filters and ignition coils (kits) to fuel pumps to cater to your needs.

2011 Audi S4 Brake Master Cylinder

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