How are Brake Master Cylinder Reservoir issues diagnosed?
Simply put, the brake master cylinder reservoir must be visually inspected to determine failure. If the technician notices the brakes feel spongy or the brake pedal sinks to the floor, he may attempt to bleed the brakes before determining where the leak in the brake system exists. In many cases, even when the reservoir can be replaced separately, the brake master cylinder and master cylinder reservoir will be replaced at the same time. This is most common when the brake fluid reservoir to master cylinder seal is deteriorated. If no brake issues are noted, the technician will note the location of any leaks or cracks, and recommend replacement of the reservoir, seals, or master cylinder and reservoir assembly.
How are Brake Master Cylinder Reservoirs replaced?
Depending on the components being replaced, this can be as simple as removing the lid and placing a new lid on the reservoir, or it can be as difficult as replacing the master cylinder as a whole. The worst case scenario will require the brake master cylinder to be removed, so let's take a look at how that is accomplished. First, the technician will begin by draining the brake fluid from the system, especially since the new brake master cylinder will require new fluid and bleeding of air. Then, while the brake master cylinder is still firmly attached to the brake booster, the brake lines will be removed, and excess fluid will be caught with rags or a drip pan, ensuring that the brake fluid is not allowed to drip on any painted surface. Next, fasteners which attach the brake master cylinder will be removed, and the brake fluid level sensor and brake pressure switch will be disconnected if equipped. Afterwards, the new brake master cylinder with the attached brake master cylinder reservoir can be mounted, electronic switch connectors installed, and brake lines can be installed as well. Lastly, the reservoir will be filled with the appropriate grade of brake fluid, and the entire system will be flushed of the old brake fluid and bled of air before testing.