Flushing Hydraulic System

Whenever new brake components are installed in the hydraulic system, it is recommended that the entire hydraulic system be thoroughly flushed with clean brake fluid. If brake fluid becomes contaminated, it may lose some of its original qualities. It is good practice to bleed the brake system until all old fluid is removed when performing major brake work. Old fluid should be bled from the system and replaced with new brake fluid if any of the hydraulic system parts are corroded or the fluid is discolored or dirty. If any of the rubber parts of the hydraulic system are soft or swollen, old fluid should be removed and all rubber components in the hydraulic system should be replaced. Do not reuse old brake fluid at any time. In the event that improper fluid has entered the system, it will be necessary to service the system as follows:
- Drain the entire system.
- Thoroughly flush the system with brake fluid.
- Replace all rubber parts of the system, brake hoses and combination valve.
- Refill the system.
- Bleed the system.

Fig. 27 Flushing Hydraulic System:

Flushing is performed at each wheel in the same manner as the bleeding operation except that the bleeder valve is opened 1-1/2 turns and the fluid is forced through the lines and bleeder valve until it emerges clear in color. Approximately one quart of clean brake fluid is required to flush the hydraulic system. After completing the flushing operation at all bleeder valves, check to ensure the master cylinder is filled to the proper level.