Dismantling and assembling primary pump - AR27.30-P-0660-02A

WARNING: This page does not describe the selected car, but rather 42 other vehicles, including the 1999 Mercedes-Benz S600, 1999 Mercedes-Benz S500, 1999 Mercedes-Benz S420, 1999 Mercedes-Benz S320, and 1999 Mercedes-Benz CL600. However, it is still accessible from the selected car via links, so may be relevant.

Remove intermediate plate.
Remove radial seal ring (6) and replace.

If the radial roller bearing (20) is damaged, the primary pump must be replaced.
Replace O-ring (7).

Install O-ring (7) in the groove so that it is not twisted.

Fig 1: Identifying Roller Bearing, Radial Seal Ring And O-Ring
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Remove/install both pump gears (3 and 4) in pump housing.

Check pump and pump gears and replace if necessary.

Oil the pump gears (3 and 4) before installing.

Install pump gear (4) with the chamfer (arrow) facing the radial roller bearing (2).

Fig 2: Installing Pump Gear With Chamfer
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.