I have a well used 410b that recently developed a loud pulsating noise in the hydraulics. The noise changes with engine rpm, and when you use one of the bucket or loader functions the noise goes away while the ram is operating. I changed the hydraulic fluid in the transmission 2times because it was milky, replaced the hydraulic filter and cleaned the screen on the line coming from the bottom of the transmission sump. I'm at a loss of where to look next any help would be greatly appreciated. Thanks in advance.
Welcome to HEF Benny ! Pump drive coupler in good shape? Has the screen in the priority valve (pressure line from pump goes there first) been removed and inspected? Any debris in the filter or screens? What oil did you use?
I haven't checked the priority valve screen, or the coupling. I will do that next, there was plenty of debris in the suction screen in the sump. This started before I changed the oil but I replaced it with Napa oil that met hy gard specs. Thanks
Well I removed the priority screen and it was clean as can be, and I checked the pump drive coupling and it seemed fine. Im not sure where to look next. It seems like its building pressure and then dumping it like a weak relief valve or a weak bypass valve, or something. Thanks again for the help.
Next would be to check charge pressure and standby pressure. I suggest, if you don't already have it, is to acquire the operation and Test Manual TM1468.