Brake Repair: Manual Bleeding

There are two general methods used for bleeding air from a hydraulic brake system. The manual method, and incidentally, the only one that can be done without costly equipment and professionals, requires two people. This typical and regularly needed car repair can be done without the help of a brake repair specialist only if you are sure that the remedy is going to fix the issue at hand and if you are skilled and knowledgeable in auto mechanics. Your helper need not be an expert.

When bleeding brakes by the manual method, it is necessary to watch the level of the fluid in the master cylinder. If the fluid gets too low, air will be drawn into the cylinder causing an endless process. So if it is a possibility, bleed the master cylinder first. To proceed with the manual bleeding of the system, if a method is not otherwise mentioned in your factory issued owner’s manual, start at the rear wheels going right to left and then proceed to right to left on the front wheels. Right and left are determined from a driver’s prospective.

First, a hose must be attached to the bleeder valve of the wheel at hand and the other end must be immersed in a glass jar of brake fluid. This stops the waste of the fluid and allows for bubbles, which indicate air, to be seen. It should be noted that when dealing with brake fluid, it is proper to allow no other substance to mix with it, including water or just pure moisture from the elements.

Opening the bleeder valve, have your helper slowly press the brake pedal to the floor. Close the valve and have your pedal pushing partner slowly release pressure off the brake pedal. Pause for a fifteen second pause to allow for the collection of air pockets. This, in theory, will make the process faster as large pockets of air will escape more rapidly than several smaller and scattered pockets. Repeat this procedure until no air is coming from the hose and into the glass jar. That is, no bubbles can be detected in the brake fluid in the glass jar. The same procedure should be competed for each remaining wheel in the aforementioned order or in accordance with your owner’s manual suggestions.

After successfully bleeding all the lines, check the master cylinder reservoir for proper brake fluid level. It should be filled approximately to one fourth of an inch from the top of the container, or to the fill line if one is indicated on the container.