Hi folks, I recently purchased a 2009 M5040DT, no cab, 300 hours. I soon noticed an irregular knocking/gurgling noise in the power steering hydraulics, if I hold the metal pipe I can feel air making its way through the loop. Putting my ear to the pump, there's an occassional swishing sound that sounds like it is picking up some air. I've just changed the fluid and filters, same problem before and after. The fluid level is good, there's some bubbles but it doesn't look to be excessively foaming. I checked the o rings on the pump suction pipe, they look fine but I've ordered new ones anyway to rule that out.
Questions:
Would a worn shaft seal on the pump suck air, or blow out fluid? Seems you can't buy just the seal for this pump but have to get the full seal kit at $400.
Can I rule out cavitation as opposed to a suction leak? I don't have much experience with this, but it sounds like cavitation is more a regular noise whereas this is erratic? Also, would cavitation create gas/air bubbles that travel through the system, or would it make a noise just in one place? At the advice of the dealer I tried removing the oil cooler bypass valve, but that had no affect.
Any advice would be greatly appreciated, this is starting to nag me. The steering and the hydraulics all work great, no noise or stutters.
Questions:
Would a worn shaft seal on the pump suck air, or blow out fluid? Seems you can't buy just the seal for this pump but have to get the full seal kit at $400.
Can I rule out cavitation as opposed to a suction leak? I don't have much experience with this, but it sounds like cavitation is more a regular noise whereas this is erratic? Also, would cavitation create gas/air bubbles that travel through the system, or would it make a noise just in one place? At the advice of the dealer I tried removing the oil cooler bypass valve, but that had no affect.
Any advice would be greatly appreciated, this is starting to nag me. The steering and the hydraulics all work great, no noise or stutters.