420890 Volvo.Penta Flywheel housing

Note: Because the accumulator operates with a low pressure, a low pressure gauge is needed for this procedure.Periodic measuring of the accumulator's pressure can help detect wear of the accumulator's seals.If oil leaks past the piston's O-ring seal into the upper portion of the accumulator, the pressure in the upper portion will increase.If nitrogen gas leaks past the piston's O-ring seal into the lower portion of the accumulator, the pressure in the lower portion will decrease. Low pressure can also be caused by nitrogen gas that leaks from the seals for the gas valve and/or for the end caps.Checking the Pressure
Note: The Tool Operating Manual, NEHS0742 is provided with the tool.
Illustration 1 g00995703
Assemble the following parts according to Tool Operating Manual, NEHS0742: nipple (1), needle valve (2), pipe tee (3), coupling (4), low pressure gauge (5), chuck (6) and hose (7). Make sure that needle valve (2) is closed.
Illustration 2 g00995678
Gas valve
Remove the guard and the cap in order to access the gas valve.
Connect chuck (6) to the gas valve. Turn the chuck's handle in order to open the gas valve.
Wait until the low pressure gauge stabilizes. Read the gauge. For the correct pressure, refer to the engine's Specifications manual.If the pressure is correct, proceed to Step 5.If the pressure is too low, proceed to "Charging the Accumulator".
Turn the chuck's handle in order to close the gas valve. Open needle valve (2) in order to purge the nitrogen gas from the tooling.
Remove the tooling from the gas valve. Install the cap and the guard over the gas valve. Charging the Accumulator
Note: Only use dry nitrogen gas to fill the accumulator.
Illustration 3 g00995724
Assemble the following parts according to Tool Operating Manual, NEHS0742: hose (1), nipple (2), coupling (3), regulator (4) and coupling (5). Connect coupling (5) to the nipple that is on the needle valve.
Crack the nitrogen bottle's valve in order to purge any debris from the valve.
Make sure that regulator (4) is closed. Make sure that the nitrogen bottle's valve is closed and connect the regulator to the nitrogen bottle.
Open the needle valve. Open the nitrogen bottle's valve. Observe the pressure gauge on regulator (4) and open the regulator's valve until some pressure is indicated on the regulator's gauge. Then close the regulator's valve.
Wait for 10 to 15 minutes in order to allow the temperature of the nitrogen gas to stabilize. Read the low pressure gauge. For the correct pressure, refer to the engine's Specifications manual.If the pressure is too low, repeat Steps 4 and 5 until the correct pressure is achieved.If the pressure is too high, perform Step 5.a through Step 5.c.
Close the needle valve and disconnect coupling (5).
Open the needle valve and then close the needle valve in order to purge some of the nitrogen gas from the accumulator.
Wait until the low pressure gauge stabilizes. Read the gauge. Repeat Step 5.a through Step 5.c until the correct pressure is achieved.
Turn the chuck's handle in order to close the gas valve. Open the needle valve in order to purge the nitrogen gas from the tooling.
Remove the tooling from the gas valve.
Close the nitrogen bottle's valve. Remove the tooling from the nitrogen bottle.
Install the cap and the guard over the gas valve.