Brake Master Cylinder

Given that the master cylinder will wear through normal use and can become corroded over time, it’s essential to replace it in order to avoid the risk of brake failure. A vital part of your car’s braking system, the master cylinder converts the pressure created by your foot pressing down on the brake pedal into hydraulic pressure, which builds up as brake fluid becomes trapped. This hydraulic pressure sets the whole braking mechanism into action, ending with the wheel cylinders demobilising the wheels. The master cylinder is a complicated piece of machinery, itself having several components. These include the housing, bore, brake fluid reservoir, fluid level sensor, piston(s), rubber cap, return spring and, in a manual car, rubber boot. Hydraulic pressure is instigated when the spring, cup and pistons slide in the cylinder bore. As an extra safety measure, modern vehicles usually have dual master cylinders, each with a different system of brake-circuit operation. If one cylinder fails (perhaps through the loss of brake fluid), the other will be able to work alone until the malfunctioning cylinder can be replaced. A common cause of failure is contamination or loss of brake fluid; if brake fluid becomes hygroscopic (attracting water), it will affect the system.

The brake master cylinder is the hydraulic pressure part of the brake system which holds brake fluid in a reservoir. When you push the brake pedal down the plunger inside the brake master cylinder housing is forced forward which transfers pressurized fluid to the brake calipers or wheel cylinders which then actuates the brake system to slow the car down. The master cylinder is divided into two separate sections, a primary and secondary pressure system. This safety system was created inside the master cylinder so if one half of the brake system fails the car will still have the remaining half to help slow the vehicle. This safety is divided into front or rear brakes.

The master cylinder is constructed with rubber seals which in time can go bad and allow the brake fluid to bypass internally or leak out from the rear of the master. When the brake master goes bad the brake pedal will sink and the brake warning light will come on. This condition will greatly decrease the stopping ability of the car. Inspect for brake fluid leakage around the master cylinder and check the fluid level regularly. If leakage is present replace master cylinder immediately. If the master cylinder actuator rod is adjusted to far out it will not allow the brake master plunger to fully return creating residual brake pressure which causes the brakes to lock up and not allow the car to roll. There must be 1/16 of an inch or 1.5 mm clearance between the master cylinder and the brake booster or pedal rod.

Most of the time, if a brake component needs replacing, it leaves a trail to follow. This trail is made of stinky brake fluid. That's the good news. Following a trail of brake fluid will usually lead you to a current or future brake problem. There are lots of brake components that can go bad. You've got wheel cylinders, master cylinders, discs, boosters, ABS systems and even brake pads. Any of these things can make your brakes more exciting than you ever hoped. Excitement is not something we want out of our brakes.

When you step on the brake pedal in a vehicle to slow it down, its braking system uses a brake master cylinder to convert the pressure you place on the pedal into hydraulic pressure. The conversion of the pressure takes place because the brake master cylinder transfers brake fluid to the braking circuit as you step on the brake pedal. The brake master cylinder will do this no matter if your vehicle is using disc brakes or drum brakes. There is no way any braking system could exist without a brake master cylinder. Warning Light – The first symptom that is the easiest to notice is when the Brake Warning Light illuminates on the dashboard. This indicates that there is problem with the braking system, so it might not necessarily mean that the brake master cylinder is at fault. But if the braking system sensors detect the brake fluid pressure is dropping, it will likely be due to a bad brake master cylinder. This will result in the warning light coming on. Leaky Brake Fluid – The brake master cylinder needs a certain level of braking fluid to create the hydraulic pressure necessary for slowing down the vehicle. If the brake master cylinder is leaking braking fluid or if there are unsecured reservoirs on the cylinder which are holding the fluid, then you will have a low brake fluid level for sure. This will impair your ability to slow down the vehicle. You would need to replace the brake master cylinder in this situation. Spongy Brake Pedal – When the brake pedal starts to feel spongy as you place pressure on it with your foot, this will automatically be a sign that your brake master cylinder is having issues. The cylinder contains rubber seals which keep the brake fluid inside of it. If these rubber seals were to get worn out or damaged, then there’d be an internal brake fluid leak. The result of this would be a spongy feeling in the brake pedal. Contaminated Brake Fluid – Another problem that could happen as a result of worn out rubber seals is contamination in the brake fluid. The seals not only help keep the brake fluid from coming out, they also prevent dirt and debris from mixing with the brake fluid. If this were to happen, the brake pressure would not be as strong as you step on the brake pedal. You’d probably end up pressing down harder on the pedal just to get the vehicle to slow down like normal. Sinking Brake Pedal – Following all these other symptoms, you will start noticing the brake pedal not returning to the top after you’ve removed your foot from it. Instead, it will slowly sink to the floor. This could become a real driving hazard, so you’ll want to fix the brake master cylinder right away at this point.

    In extreme cases, a contaminated air filter can turn on the check engine light. An extremely dirty air filter restricts engine air intake. Engine misfire. A misfire results from incomplete combustion inside the engine. A contaminated air filter can restrict engine airflow, resulting in a rich air and fuel mixture.

    Sometimes, the worst part of getting your car fixed is having to bring it to the garage. We are therefore happy to offer our customers a free collection and delivery service If you prearrange a collection, we will pick your car up from your home or place of work and drive it to our premises, carry out all the necessary work (having consulted you) and deliver it back to you at the end of the day.

    We are able to tow, jump start or repair your vehicle if you are experiencing problems or broken down for a small fee. If we can’t sadly start your vehicle, we can contact a local recovery firm to collect your vehicle for a very competitive price.

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    Many Autos operate a fleet of pool cars with a dedicated driver, so wherever we are collecting from, we need to be able to leave one of our pool vehicles either in your work car park / parking space, or if in a residential area, we would need to be able to leave our car either at your house or on the road with a permit if required. We would be grateful if you could bear this in mind when booking to use our free Collection and delivery service

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