2002 Mercedes-Benz ML320 Brake System Inspect Cost

Brake system inspections are necessary to be performed for all vehicles at different intervals throughout their service life. This can take seconds or minutes, and the intent is to uncover anything that could cause a safety concern. A technician will inspect the various parts of the brake system, drive the vehicle to test the brakes, and note any inefficiencies or adverse conditions. In order to perform this inspection, the technician must know and understand the components of the brake system, even on highly sophisticated models with advanced engineering.

The brake system begins at the brake master cylinder and reservoir. These components supply the fluid and create high pressure needed to actuate the rest of the system. The brake pedal will press the power brake booster, which will press the brake master cylinder. Pressurized fluid from the brake master cylinder is sent through the anti-lock brake modulator valve, where it undergo changes in pressure due to anti-lock brake control module requests. The fluid will then flow from the anti-lock brake modulator valve, and to the wheels where it will enter either wheel cylinders or brake calipers. Note, some vehicles will have a proportioning valve to direct the pressures to the different ends of the vehicle, and some will not have ABS. At the brake calipers or wheel cylinders, the brake pads or shoes, respectively, will be pressed into the brake rotors or brake drums, also respectively. All of these components work together in a chain reaction in order safely slow and stop a vehicle.

Most often, a brake system inspection will just be a routine portion of manufacturer specified maintenance, and will be performed at mileage intervals. In those cases, there will likely be no symptoms. However, when a brake system makes a funny noise, causes vibration, is hard to use, will not slow the vehicle, prevents the vehicle from driving, makes the vehicle pull to one side, or leaks brake fluid, the vehicle will need a visit dedicated to the inspection of the brake system.

Any problem with the brake system from squeaky brakes to total failure should be inspected immediately. When attempting to stop a vehicle with a faulty brake system, the likelihood of brake failure is high, and the parking brake is not a sufficient substitute for the service brake. This can pose a serious hazard to passengers and other vehicles on the road. If the brake warning light illuminates, the vehicle should not be driven, as a brake fluid leak will eventually cause total brake system failure.

Since brake system inspections are based on factory scheduled maintenance intervals, the frequency of this inspection should only be as often as the manufacturer suggests. However, as brakes tend to wear out between the 40,000 - 70,000 mile range, even vehicles which have been neglected will receive a brake system inspection within this interval.

Inspection can begin or end at any point on the brake system, but typically physical inspection will occur after the technician has read the customer complaint and driven the vehicle if safe and possible. During the test drive the technician will look for things like vibration in the steering wheel and brake pedal when slowing or stopping, squeaks and rattles that change when the brakes are applied, and the feel of the brakes overall. During the physical inspection, any issues noted with the brakes will call attention to specific areas or components, but the inspection will be exactly the same as if the vehicle were in for scheduled maintenance. The brake fluid condition and level is checked, the system is inspected for leaks, drum brakes are cleaned and adjusted if needed, and brake pad and shoe thickness are checked against specifications for the specific vehicle. Some fasteners may be checked for tightness, and the brake line mounting hardware will be checked to ensure it is present and intact. When any issue is found, the technician will have a diagnosis right away, but further inspection may be required.

Depending on the service needed for a vehicle, including brake flushing and bleeding, master cylinder or power brake booster replacement, full brake pad and rotor service, or just cleaning and adjusting rear brake drums, the procedure will vary greatly. One portion of most brake system repairs and services performed is flushing and bleeding the brake system. In most instances, if the brake lines must be opened or disconnected for any reason, the old fluid is flushed out while bleeding the brakes, which provides better protection for the brake system components, and ensures all of the air and contaminants are out of the brake system.

We recommend using the factory approved brake fluid for the vehicle being repaired, and not mixing any types of brake fluid. Also, the brake system should be flushed and inspected for obvious signs of deterioration, and repaired if necessary to prevent further failure. If the Entire brake hydraulic system is replaced, a new type of brake fluid may be used, but it must be at least the minimum standard of when the vehicle was manufactured. Also, each vehicle has a factory specified maintenance interval based upon engineering and research pertaining to the system being serviced. Following the factory scheduled maintenance interval for brake inspections and services can greatly reduce the chances of future brake system failures.

Mixing brake fluid can lead to brake system failure due to congealing of the fluid within the brake lines. The different types of brake fluid, i.e. DOT3, DOT4, or DOT5 are meant for higher and higher braking demand, and will not always result in better braking performance. In fact, except for the most strenuous braking conditions, upgrading brake fluid will likely have no benefit.

Inspecting the brake system for possible failures and safety concerns can be done by anyone with a good understanding of brake hydraulic, pneumatic (vacuum) and mechanical systems. This knowledge is necessary to properly notice, diagnose, and repair brake system failures or wear and tear which are often found on vehicles. Also, many brake systems have electronic components such as the anti lock brake system control module which may need to be scanned to identify the cause of failure. Not all consumer grade scanners are built for this task, and a professional may be needed due to the high cost of professional scanning software or equipment.