Replacing the check valve of the throttle valve servo of the 1st chamber (BMW 5 Series E12)

The check valve is installed in the vacuum supply channel to the servo drive. The main parts of the check valve are the diaphragm 1, piston 2 and spring 3. To replace the check valve:

• remove the carburetor; screw the M4 bolt into the valve cover and remove the cover;
• remove the check valve parts (it is prohibited to use a sharp instrument for this purpose);
• install the new valve parts in the reverse order of removal, making sure that no dust or dirt gets inside the valve;
• insert the valve cover;
• after installing the check valve, make sure it is tight.