E Class L4-135 2.2L SOHC VIN D TBI (1984)
Brake Bleeding: Service and Repair
About Brake System Bleeding
The following notes apply to master cylinders without proportioners or pressure control valves located in the master cylinder outlet ports:
Some models incorporate a self-centering valve. After any bleeding operation, turn ignition switch to ACC or ON position and depress brake pedal.
Valve will center itself.
Some cars with disc brakes are equipped with front disc brake pressure metering valve which is located on the left frame rail directly under the battery.
The purpose of the metering valve is to provide a better match of the front disc brakes with the rear drum brakes, resulting in improved braking balance
in light pedal applications.
Gravity bleed and pedal methods are not affected by the presence of the metering valve. However, pressure bleeding is influenced by the metering valve.
Bleed pressure, which is normally about 35 psi, is high enough to cause the metering valve to close, which stops the flow of fluid to the front brakes.
However, the valve can be held open manually by depressing the pressure release plunger (located at the bottom of the valve) in its uppermost position
by hand or secured with masking tape while bleeding the brakes.
Under no conditions should a rigid clamp, wedge or block be used to secure the plunger as this can cause an internal failure in the valve. It should be
noted that the pressure release plunger of the valve is already in its uppermost position when there is no pressure present.