Removing, installing, dismantling and assembling secondary pump (transmission in situ) - RA27037220530X(27-530)

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.

Operation number of the operation texts and work units or standard texts and flat rates:

27-5206, 27-5205.

Fig 1: Identifying Secondary Pump Components

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

NOTE: Observe removal and installation notes of op. no. 27-600.

Transmission	Lower a little at the rear, removing rear engine mount. Disconnect, connect exhaust system at rear.
Nut for axial retainer (44)	Unscrew, screw on.
Hexagon socket bolts (45)	Unscrew, screw in and remove secondary pump (20), 8 Nm.
O-ring (18) and intermediate plate (19)	Remove, install.
Pump gears (22, 23)	Remove from housing. When removing, lubricate the gears and insert into the grooves (item 1).
Cover (27)	Remove after removing the circlip (28) (item 2).
Pressure spring (24), spring plate (25), switch-off plunger (21)	Remove from pump housing (20), check O-ring (29) and Teflon rings (30 and 31) and replace if necessary (items 3-5).

Dismantling and assembling

Remove pump gears from housing.
Remove circlip (28) and cover (27).

Fig 2: Identifying Circlip And Cover
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Installation note

Lubricate pump gears (22) and (23) and insert in the pump housing. Insert the driving pump gear (22) so that the drivers (arrow) are facing upwards.

Fig 3: Identifying Lubricate Pump Gears And Driving Pump Gear
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Remove switch-off plunger (21) with pressure spring (24) and spring plate (25) from pump housing.

Fig 4: Identifying Switch-Off Plunger With Pressure Spring
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Remove O-ring (29).
Check all parts for damage and wear. The gap between the two Teflon rings (30, 31) must be completely closed, if necessary insert the Teflon rings into the grooves with a little grease.

Fig 5: Identifying O-Ring And Teflon Rings
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Vehicles without secondary pump, as of 06/91

Removal, installation

Unscrew nut for axial retainer (44).
Unscrew hexagon socket bolts (45) and remove secondary pump (20).
Installation note

The slot (arrow) in the axial retainer (43) must be horizontal.

Fig 6: Identifying Unscrew Nut For Axial Retainer And Unscrew Hexagon Socket Bolts
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Fig 7: Identifying Transmission Housing, Lower Cover And Gasket
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

The bores in the transmission housing for the secondary pump are sealed off by means of a cover (17) and gasket (18).

Fig 8: Identifying Cover, Gasket And Snap Ring
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.