Hydraulic system - Draining and refilling - RA32001290630X(32-0630)

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.

Preceding work:

Lower engine compartment lining removed

Operation no. of operation texts and work unit or standard texts and flat rates

32-0800

Model 129

Fig 1: Identifying Hydraulic System - Draining And Refilling

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

DRAINING PRESSURE OIL SYSTEM

Bolt (50a)	on distribution valve (50), unscrew by approximately 1 turn (Position 1). NOTE: The Allen bolt (50a) was replaced by a hexagon bolt in 09/90.
Connecting rod/control rod (54, 55)	remove from level controller lever.
Oil drain hose	plug onto, remove from fluid drain plug (3p, 6p) on the level controller (3, 6). Ensure that the front wheels are pointing straight ahead.
Oil drain plug (3p, 6p)	open slowly and drain the fluid into a clean container. Then recluse the drain plug (3p, 6p), 14 Nm (Position 5).

FILLING PRESSURE OIL SYSTEM

Level control switch	put into "normal level" position. The red indicator lamp in the switch must not light up.
Oil reservoir (2)	fill hydraulic oil into the oil reservoir (2) with funnel 126 589 12 63 00, until the oil level is between the "min." and "max." marking on the oil dipstick.
Lever on level control unit	press into position "Fill" (No. 8).
Engine	allow to run at approx. 2000 rpm, until level of vehicle visibly rises at front and rear axle. Switch off engine. Pay attention to oil level in oil reservoir (note information No. 9).
Screw (50a)	screw into distributor valve (50).
Connecting rod/control rod (54, 55)	install on level controller lever (3, 6). Replace self-locking hexagon nut, 10 Nm.
Engine	start, allow to run at approx. 2000 rpm.
Pressure oil system	fill until the normal vehicle level is reached, while noting the oil level.

If during repair work the oil reservoir (2) has been emptied or the pressure oil pump (1) replaced or the high pressure extending hose (4) has been replaced or unscrewed, the pressure oil pump must be bled.

Special tools

Fig 2: Identifying Special Tools (126 589 12 63 00 27 32)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Fig 3: Identifying Special Tools (589 00 17 00 32)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

SERVICE PRODUCTS AND CAPACITIES

Hydraulic fluid	see Specifications for Service Products, Page 343 (1.0 liter can, Part No. 000 989 91 03/10)
Total capacity of system	approx. 4.5 l

Use a line wrench for tightening the pressure lines, and under no circumstances a normal open-end wrench in order to avoid damage to the line connections. Use special tool to improve access to individual line connections.

Only use solid copper sealing rings of the specified dimensions for the banjo bolts. Always replace sealing rings.

NOTE: The pressure oil pump has its own lubrication, i.e. the oil delivered acts simultaneously as lubricant.

Scope of work

Draining pressure oil system

Unscrew bolt (50a) approximately one turn using 4 mm Allan key.

Fig 4: Identifying Bolt And Distribution Valve (Version Installed Up To 8/90)
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

NOTE: In 9/90 the Allen-type pressure supply bolt (50a) was replaced by a 10 mm hexagon bolt.

Fig 5: Identifying Allen-Type Pressure Supply Bolt And Distribution Valve (Version Installed Since 8/90)
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
If connecting rod/control rod is fitted. Remove connecting rod/control rod (54) at the lever of the level control unit (6). If necessary use open-end wrench to hold hinge pin in position.

Fig 6: Identifying Connecting Rod/Control Rod And Level Control Unit
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Ensure that the front wheels are pointing straight ahead.
Slowly open oil drain plug (6p) while collecting the oil in an oil reservoir (2). Then retighten oil drain plug, 14 Nm.

Fig 7: Identifying Oil Drain Plug, Oil Reservoir And Oil Drain Plug
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
If connecting rod/control rod is fitted. Remove connecting rod/control rod (55) at the lever of the level control unit (3). If necessary use open-end wrench to hold hinge pin in position.

Fig 8: Identifying Connecting Rod/Control Rod And Level Control Unit
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Plug the fluid drain hose (061) onto the level controller's (3) fluid drain plug (3p). Slowly open the drain plug (3p) and allow the fluid to drain into a clean container. Then recluse the drain plug, 14 Nm.

Fig 9: Identifying Drain Hose, Level Controller'S And Drain Plug
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Fig 10: Identifying Level Controller'S And Drain Plug
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Filling pressure oil system

(except for USA model)
Move level control switch (S77) into "normal level" position. Red indicator lamp in switch must not light up.

Fig 11: Identifying Level Control Switch
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Fig 12: Identifying Fluid Reservoir With Connections
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

All models
Use funnel with strainer (060) to fill oil reservoir (2) with oil, until the oil level is between the "min." and "max." markings on the oil dipstick.
NOTE: Only re-use clean oil.

Fig 13: Identifying Strainer And Oil Reservoir
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Move lever (6a, 3a) of level control unit on front and rear axle into position "Fill".

Fig 14: Identifying Lever Of Level Control Unit On Front Suspension
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Fig 15: Identifying Lever Of Level Control Unit On Rear Suspension
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Allow engine to run at approx. 2000 rpm until the level of vehicle rises visibly at front and rear axle. Note oil level in oil reservoir.
NOTE: The hydraulic system is not fully charged until the vehicle's suspension has extended to its maximum height. This procedure may be accompanied by whistling and bumping noises. The bolt (50a) in the distribution valve (50) must be open while the system is being charged (Position 11).
Switch off engine.
Screw bolt (50a) into distributor valve (50).

Fig 16: Identifying Bolts And Distributor Valve (Version Installed Up To 8/90)
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Fig 17: Identifying Bolts And Distributor Valve (Version Installed Up To 9/90)
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Mount the linkage rod/control rod (54, 55) on the lever on the level controller (rear suspension), or on the lever on the torsion bar (front suspension), 10 Nm.
Shown on rear axle

Fig 18: Identifying Control Rod, Level Control Unit And Rear Axle
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Start the engine and let it run at about 2000 rpm.
Charge the hydraulic system until the vehicle reaches its normal ride height. Monitor the fluid level continuously during this procedure.
When engine is not running, oil level in oil reservoir must be between the markings "max." and "min.".

Fig 19: Identifying Oil Reservoir, Oil Dipstick And Sealing Cap
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

If during repair work, the oil reservoir has been emptied or the pressure oil pump replaced or the high pressure extending hose is replaced or unscrewed, the pressure oil pump must be bled. For this step, when the engine is running the high pressure extending hose disconnected at the steel line (P) must be held in a container, until no bubbles appear in the escaping oil.

Then repeat the work steps Nos. 6-14.

Fig 20: Locating High Pressure Extending Hose

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

NOTE: After charging the hydraulic system, discharge the remaining air from the system by taking the vehicle for a test drive on an undulating, uneven road surface. Then recheck the fluid level (Position 14).

Model 140

Fig 21: Identifying Hydraulic System Draining Points

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

DRAINING PRESSURE OIL SYSTEM

Linkage (7)	remove, install at lever on level control unit.
Oil drain hose (061)	attach, remove at oil drain plug (3p) on level control unit (3).
Oil drain plug (3p)	open slowly, while catching the oil in a clean container. Then retighten oil drain plug (3p), 14 Nm.

FILLING PRESSURE OIL SYSTEM

Oil reservoir (2)	fill hydraulic oil into the oil reservoir using funnel 126 589 12 63 00, until the oil level is between "min" and "max" markings on the oil dipstick.
Lever on level control unit	press into position "Fill". Install linkage (7), replace self-locking bolts, 10 Nm.
Engine	start and allow to run for approx. 30 seconds in the middle speed range, then switch off engine (note information in No. 8)
Oil level	check in oil reservoir, the oil level must be between the "min" and "max" markings when the engine is not running.

Special tool

Fig 22: Identifying Special Tools (126 589 12 63 00 27 32)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

SERVICE PRODUCTS AND CAPACITIES

Hydraulic fluid	see Specifications for Service Products, Page 343 (1.0 liter can, Part No. 000 989 91 03/10)
Total capacity of system	approx.	2.0 l

Scope of work

Draining pressure oil system

If the linkage is fitted. Remove linkage (7) at lever on level control unit.

Fig 23: Identifying Linkage
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

NOTE: Designations on level control unit

A=Model 140 with level control on rear axle

B= Model 140 with level control on rear axle and ADS.

Model 140 with level control on rear axle and ASD.

Fig 24: Identifying Lever Control Unit, Connector And Oil Drain Plug
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Modified fluid drain plug on level controller

A new fluid drain plug (3m) was installed at connection "S2" on the level controller. The earlier connection fitting (3m) was deleted at the same time. Tightening torque for fluid drain plug: 14 Nm.

Fig 25: Identifying Connection Fitting And Fluid Drain Plug
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Attach oil drain hose (061) to oil drain plug (3p) on the level control unit (3).
Slowly open oil drain plug (3p) while collecting the oil in a clean container. Then retighten oil drain plug, 14 Nm.

Fig 26: Identifying Oil Drain Hose, Oil Drain Plug And Level Control Unit
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Filling pressure oil system
Use funnel with strainer (060) to fill oil reservoir (2) with oil collected.
NOTE: Only re-use clean oil.

Fig 27: Identifying Funnel With Strainer And Oil Reservoir
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Check oil level in oil reservoir, top up if necessary. To fill the system when spring struts are empty the oil level should be approximately at the maximum marking (a).
Move lever on level control unit into position "Fill" and allow engine to run at medium speed for approx. 30 seconds.

Fig 28: Moving Lever On Level Control Unit
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Install linkage rod (7) using new self-locking hexagon bolts, 10 Nm.

Fig 29: Identifying Linkage Rod And Self-Locking Hexagon Bolts
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Check oil level in oil reservoir (2) when engine is not running and correct if necessary. When the system is operational the oil level should be between markings "max." and "min" at curb weight. If the vehicle is fully laden the oil level is thus below the "min" marking (no longer visible on dipstick).
NOTE: Only use approved hydraulic fluids.

If during repair work the oil reservoir has been emptied or the tandem pump replaced or high pressure extending hose unscrewed, the pump must be bled.

Fig 30: Identifying Oil Reservoir
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

must be bled.

For this step, when the engine is running press the lever of the level control unit into position "Empty" or "Neutral" to ensure the oil returns to the oil reservoir (this is already the case on a raised vehicle). If no oil is supplied to the oil reservoir on ASD vehicles, also hold the high pressure extending hose disconnected at the steel line in a container until no bubbles appear in the escaping oil. Then repeat the work steps Nos. 4 - 8.