Replace valve stem seals with cylinder head installed

AR05.30-G-3512DD

Replace valve stem seals with cylinder head installed

21.08.2019

Engine

900.91/92 in model 000.001

Engine

902.91/93 in model 000.001

Engine

904.94/95/96/97 in model 000.001

Engine

906.90/93/94/95/96/98/99 in model 000.001

Engine

924.91/93/94 in model 000.001

Engine

925.9 in model 000.001

Engine

926.91/92/93/95/97/98 in model 000.001

Modification notes

19.03.2019

Document completely revised

Shown on engine 900.9

1

Valve stem seal

2

Valve spring

3

Retaining clip

 Danger

Risk of explosion due to escaping combustible gas or overheating of gas cylinders.Risk of injury caused by burns to skin and eyes. Risk of frostbite to body parts caused by escaping gas and by touching components near the valves when emptying gas cylinders. Risk of poisoning or suffocation caused by inhaling gas.

Remove any sources of ignition.
Protective clothing, safety gloves and safety glasses must always be worn.
Ensure that the work area is adequately ventilated.
When working on vehicles at ambient temperatures over 60 °C, all gas cylinders must be removed.

AS00.00-Z-0018-01A

 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

 Caution

Risk of injury to skin and eyes due to handling of engine oil. Risk of poisoning caused by swallowing engine oil

Wear protective gloves, protective clothing and safety glasses.
Do not fill engine oil into beverage containers.

AS18.00-Z-0001-01A

Notes on work safety regulations for vehicles with natural gas-powered engines

AH00.10-N-1000-04A

Firing order

AH01.00-N-0100-01AA



Remove

1

Remove cylinder head cover.

Natural gas engine

AR01.20-G-5014DE

Diesel engine

AR01.20-G-5014DD

2

Remove charge-air distributor.

Natural gas engine

AR09.41-G-8681DD

Diesel engine

AR09.41-G-8681DE

3

Attach the cranking device.

AR03.30-W-1600-03J

 Bolt, turning device to timing case

*BA01.60-N-1003-01I

 Turning device

*904589046300

4

Turn engine using turning device until piston on cylinder to be machined is exactly at overlapping TDC.

 Observe the firing order.

5

Remove rocker arm assembly.

AR05.00-G-5521DD

6

Remove retaining clips (3).

Replace

7.1

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

With engine 900.9, 924.9

AR05.30-G-3512-01DD



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

BT05.30-N-0004-01RH

 Ensure correct seating of the conical valve keepers in the valve spring retainer and in grooves on the valve stem.

 Pliers

*606589003700

 Valve tool case

*541589006100

 Magnetic pin

*210589004000

7.2

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

For engines 902.9, 904.9, 906.9, 925.9, 926.9

AR05.30-G-3512-01DD



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

BT05.30-N-0004-01RH

 Pliers

*606589003700

 Valve tool case

*541589006100

 Magnetic pin

*210589004000

8

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

AR03.10-G-7041-03DD

 Valve tool case

*541589006100

9.1

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

With engine 900.9, 924.9

AR05.30-G-3512-01DD



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

BT05.30-N-0004-01RH

 Pliers

*606589003700

 Valve tool case

*541589006100

 Magnetic pin

*210589004000

9.2

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

For engines 902.9, 904.9, 906.9, 925.9, 926.9

AR05.30-G-3512-01DD



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

BT05.30-N-0004-01RH

 Pliers

*606589003700

 Valve tool case

*541589006100

 Magnetic pin

*210589004000

10

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

Only for engines 902.9, 904.9, 906.9, 925.9, 926.9

AR03.10-G-7041-03DD

 Valve tool case

*541589006100

11

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

Only for engines 902.9, 904.9, 906.9, 925.9, 926.9

AR05.30-G-3512-01DD



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

BT05.30-N-0004-01RH

 Pliers

*606589003700

 Valve tool case

*541589006100

 Magnetic pin

*210589004000



Install

12

Install retaining clips (3).

 except natural gas engineBolt, retaining clip nozzle holder assembly to cylinder head

*BA07.15-N-1003-01D

13

Install rocker arm assembly.

AR05.00-G-5521DD

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

14

Set valve clearance.



AP05.30-G-0560DD

15

Install charge-air distributor.

Diesel engine

AR09.41-G-8681DD

Natural gas engine

AR09.41-G-8681DE

16

Install cylinder head cover.

Diesel engine

AR01.20-G-5014DD

Natural gas engine

AR01.20-G-5014DE

17

Remove turning device from timing case and attach cap.

AR03.30-W-1600-03J

 Bolt, turning device to timing case

*BA01.60-N-1003-01I

 Inspection hole cap to timing case

*BA01.60-N-1002-01I

 Turning device

*904589046300

18

Check/correct engine oil level.



AP18.00-G-0101DD

 For approved engine oils, see the manufacturer's Specifications for Operating Fluids.

19

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


Do not rev up engine before the full oil pressure is present.
The engine can otherwise be damaged.

 See information from body manufacturer.

20

Switch off engine and check for leak tightness.

 Perform visual inspection.

 Timing case

Number

Designation

Engine 900.9, 902.9, 904.9, 906.9, 924.9, 925.9, 926.9 in model 000.001

BA01.60-N-1002-01I

Inspection hole cap to timing case

Nm

25

 Timing case

Number

Designation

Engine 900.9, 902.9, 904.9, 906.9, 924.9, 925.9, 926.9 in model 000.001

BA01.60-N-1003-01I

Bolt, turning device to timing case

Nm

25

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

Number

Designation

Engine 900.9, 902.9 (except 902.90), 904.9, 906.9 (except 906.90) in model 000.001

Engine 924.9, 925.9, 926.9 in model 000.001

BA07.15-N-1003-01D

Bolt, retaining clip nozzle holder assembly to cylinder head

Hexagon socket

Nm

30

–

Twelve-point with radius seat

Nm

35

35