HEAD AS 3665122 - Caterpillar

Introduction
The problem that is identified below does not have a known permanent solution. Until a permanent solution is known, use the solution that is identified below.Problem
The charging procedure that is currently published in the Testing and Adjusting section of the Service Manual for the above machines is correct for checking and adding charge pressure to an accumulator that has been in service for a period of time. For new accumulators or rebuilt accumulators, the currently published charging procedure can cause an accumulator bladder to rupture. The currently published procedure can also cause damage that will result in premature failure of the bladder.Solution
To ensure that a new accumulator bladder is not damaged during the charging process, use the following steps when you are charging a new accumulator or a rebuilt accumulator.Before a new accumulator or a rebuilt accumulator can be installed on a machine, the accumulator needs to be allowed to warm to room temperature. Then, use the following procedure to charge the accumulator.
Turn the adjustment knob for the regulator pressure counterclockwise until the needle for the pressure indicator on the pressure gauge moves from 0 kPa (0 psi) to 35 kPa (5 psi).
Allow the bladder to expand slowly in order to begin the process of filling the inside of the accumulator cylinder.
When the pressure reading on the charging adapter gauge and the pressure regulator gauge are identical, close the accumulator cylinder.
Allow a waiting period of five minutes for the temperature of the nitrogen inside the accumulator to stabilize.
Turn the adjustment knob for the regulator pressure counterclockwise until the needle for the pressure indicator on the pressure gauge moves to 70 kPa (10 psi).
Allow the bladder to expand slowly in order to continue the process of filling the inside of the accumulator cylinder.
When the pressure reading on the charging adapter gauge and the pressure regulator gauge are identical, close the accumulator charging valve.
Allow a waiting period of five minutes for the temperature of the nitrogen inside the accumulator to stabilize.
Repeat Step 5 through Step 8 for 345 kPa (50 psi) and 690 kPa (100 psi).
Turn the adjustment knob for the regulator pressure counterclockwise until the needle for the pressure indicator on the pressure gauge moves to the required pressure level for the machine. See the machine specification for the correct pressure.
Allow the pressure in the bladder to reach the required pressure level.
When the pressure reading on the charging adapter gauge and the pressure regulator gauge are identical, close the accumulator charging valve.
Allow a waiting period of five minutes for the temperature of the nitrogen inside the accumulator to stabilize.
If there is a decrease in pressure on the gauge for the adapter, open the charging valve. Opening the charging valve will allow more nitrogen to enter the accumulator.
Repeat Step 12 through Step 14 until the following items occur:
Pressure readings of the gauge on the adapter and gauge on the regulators are identical.
Pressure readings do not change after the ten minute stabilizing period.
Close the valve on the nitrogen cylinder.
Remove the adapter