Rebuilding the steering accumulator on my 644c john deere. Opened it up and found the piston was broke in half. Any idea what caused this? Don't want to tear it up again, I didn't do this the steering was jerky when I bought it
I would think the accumulator had lost its nitrogen charge hundreds or thousands of hours ago. Repeated start ups with no resistance would have moved the piston upwards quickly and slamming hard against the top cap. Looking at how that piston was originally machined (and failed) there was multiple opportunities for stress cracking.
That makes sense. I was thinking they had turned hard against the cylinder stops and more or less crushed it with the hydraulics. Just didn't want to repeat someone else's mistakes.
The steering accumulators purpose is to provide some reserve hydraulic pressure to the steering system if the engine was to shut down unexpectedly. Same scenario for the service brake accumulator/ braking system.