Anyone know if there is a recommended replacement interval on the accumilators in hydraulic systems on excavators? I know these typically contain compressed nitrogen in a bladder that acts on the oil. It would seem logical to assume these will lose some pressure over the years but the manuals I have for my machine make no mention of checking or replaceing it. Anyone know?
In 12 years I have never changed a acum on one of these machines and we have a ton of mid sized excavators. You need to put a gauge in the pilot system and see what your system is doing. You should pull of that pump and disassemble it as well, really simple to do. You may have some gear damage.
Most excavators use a small accumulator to provide pilot pressure should the engine break down with the implements in the air. To check yours just pick the boom all the way up, shut down the engine, turn the key back on with the lock lever in the run position. Now try to lower the boom. It should go all the way to the ground before the accumulator runs out. Most of those small accumulators are throw away units. There are larger units that operate on a piston and they give you trouble all the time. They have special fittings and procedures for charging them. If you don't know how to do those, stay away from them.
Stay away from the accumulator, it doesn't work like an absorber like say a ride control on a loader. This device will not cause your pilot system to surge, pull the pilot pump and inspect.