Replace valve stem seals with cylinder head installed

AR05.30-W-3512J

Replace valve stem seals with cylinder head installed

04.12.2019

Engine

900.9 in model 375.1, 970, 972, 975, 976

Engine

902.9 in model 375.1, 970, 972, 974, 975, 976

Engine

902.9 in model 375.3, 950.5/6, 952.5/6, 953.6, 954.5

Engine

902.9 in model 957

except code MS8 (Natural gas engine)

Engine

924.9 in model 958.0, 970, 972, 974, 975, 976

Engine

925.9 in model 970, 972, 974

Engine

926.9 in model 950.5/6, 952.5/6, 953.6, 954.5, 957, 958.2

Engine

926.9 in model 958.0

Shown on engine 900.9

1

Valve stem seal

2

Valve spring

3

Retaining clip

 Warning

Risk of accident from vehicle starting off by itself when engine running. Risk of injury (bruises and burns) resulting from working on the engine while it is being started or when it is running.

Secure vehicle to prevent it from starting off by itself. Wear closed and snug-fitting work clothes. Do not touch hot or rotating parts.

AS00.00-Z-0005-01A

Notes on engine oil

AH18.00-N-0101-01HA

Firing order

AH01.00-N-0100-01AA



Remove

1

Remove cylinder head cover

AR01.20-W-5014J

2

Remove charge air manifold

AR09.41-W-8681J

3

Remove cap of timing case and attach cranking device

AR03.30-W-1600-03J

 Bolt, turning device to timing case

*BA01.60-N-1003-01A

 Turning device

*904589046300

4

Remove soundproofing on top right of frame

5

Crank engine with turning device until piston for cylinder 1 to be inspected is positioned precisely at ignition TDC

 Observe firing order.

6

Remove rocker arm assembly

AR05.00-W-5521J

7

Remove retaining clip (3)

Replace

8.1

Remove valve springs (2) from cylinder 1 and 4; replace valve stem seals (1) and install valve springs (2)

Engine 900.9, 924.9

AR05.30-W-3512-01J



Exhaust valve spring, exhaust valve and exhaust valve seat ring modified

BT05.30-N-0004-01RH

 Magnetic pin

*210589004000

 Valve tool case

*541589006100

 Pliers

*606589003700

8.2

Remove valve springs (2) from cylinder 1 and 6; replace valve stem seals (1) and install valve springs (2)

Engine 902.9, 925.9, 926.9

AR05.30-W-3512-01J



Exhaust valve spring, exhaust valve and exhaust valve seat ring modified

BT05.30-N-0004-01RH

 Magnetic pin

*210589004000

 Valve tool case

*541589006100

 Pliers

*606589003700

9

Bring piston on cylinder 2 exactly into the top dead center position

AR03.10-W-7041-03J

 Valve tool case

*541589006100

10.1

Remove valve springs (2) from cylinder 2 and 3; replace valve stem seals (1) and install valve springs (2)

Engine 900.9, 924.9

AR05.30-W-3512-01J



Exhaust valve spring, exhaust valve and exhaust valve seat ring modified

BT05.30-N-0004-01RH

 Magnetic pin

*210589004000

 Valve tool case

*541589006100

 Pliers

*606589003700

10.2

Remove valve springs (2) from cylinder 2 and 5; replace valve stem seals (1) and install valve springs (2)

Engine 902.9, 925.9, 926.9

AR05.30-W-3512-01J



Exhaust valve spring, exhaust valve and exhaust valve seat ring modified

BT05.30-N-0004-01RH

 Magnetic pin

*210589004000

 Valve tool case

*541589006100

 Pliers

*606589003700

11

Bring piston on cylinder 3 exactly into the top dead center position

Only for engine 902.9, 925.9, 926.9.

AR03.10-W-7041-03J

 Valve tool case

*541589006100

12

Remove valve springs (2) from cylinder 3 and 4; replace valve stem seals (1) and install valve springs (2)

Only for engine 902.9, 925.9, 926.9.

AR05.30-W-3512-01J



Exhaust valve spring, exhaust valve and exhaust valve seat ring modified

BT05.30-N-0004-01RH

 Magnetic pin

*210589004000

 Valve tool case

*541589006100

 Pliers

*606589003700



Install

13

Install retaining clip (3)

 Bolt connecting retaining clip of nozzle holder combination to cylinder head

*BA07.15-N-1003-01A

14

Install rocker arm assembly

AR05.00-W-5521J

 Only install cylinder head cover after valve clearance has been adjusted.

15

Set valve clearance



Model 375, 950, 952, 953, 954, 957, 970, 972, 974, 975, 976

AP05.30-W-0560B

 Model 958
No instructions were created yet for these variants.

16

Install charge air manifold

AR09.41-W-8681J

17

Install cylinder head cover

AR01.20-W-5014J

18

Install soundproofing on frame above on the right

19

Remove cranking device at timing case and attach cap

AR03.30-W-1600-03J

 Inspection hole cap to timing case

*BA01.60-N-1002-01A

 Turning device

*904589046300

20

Check engine oil level at display; correct if necessary

 Observe engine oil quality set in maintenance system or Specifications for Operating Fluids.

21

Start engine and allow to run in idle for 10 s until the oil pressure has built up, then run the engine at varying speeds

22

Switch off engine and check for leaktightness

 Visual inspection.

 Timing case

Number

Designation

ENGINE 900.9, 902.9, 904.9, 906.9

ENGINE 924.9, 925.9, 926.9

BA01.60-N-1002-01A

Inspection hole cap to timing case

Nm

25

25

 Timing case

Number

Designation

ENGINE 900.9, 902.9, 904.9, 906.9

ENGINE 924.9, 925.9, 926.9

BA01.60-N-1003-01A

Bolt, turning device to timing case

Nm

25

25

 Diesel injection system with unit pumps (MR/PLD)

Number

Designation

ENGINE 900.9, ENGINE 902.9 except CODE MS8

Engine 924.9, 925.9, 926.9

BA07.15-N-1003-01A

Bolt connecting retaining clip of nozzle holder combination to cylinder head

Hexagon socket

Nm

30

–

Twelve-point with radius seat

Nm

35

35