SnowRidge
Elite Member
Back when it was warm out, I changed the hydraulic filter and fluid in my 3520. I used a Napa 1202 (Wix 51202) filter and Certified Universal Hydraulic Fluid purchased at Sam's Club. Everything went smoothly, and I had no problems after the change -- until the temperatures dropped.
When the ambient temperature dropped below approximately 70F, I started getting a loud hydraulic whine from the front of the machine. When I say ambient, I am referring to the outside air temperature at the time the machine was first started that particular day, and by extension the temperature of the hydraulic fluid after the machine had been sitting overnight or longer.
The whine wasn't pure, but had a rattle quality to it, and it was sensitive to both engine RPM and temperature. There was no whine below about 1500 RPM when the temperature was about 70F. As the temperature dropped, the whine started at lower and lower RPMs, until it was present at all speeds when the temperature was about 50F or below. Operating the tractor long enough (at RPMs below the threshold of the whine) eventually warmed the hydraulic fluid enough that it ceased for the day, even at PTO speed.
The whine only occurred when there was absolutely no load on the hydraulic system. As soon as the bucket was raised, empty or full, and however slowly, or if the 3PH was raised, the whine stopped instantly. It never tapered off or came on gradually. It was either there or not. At no time has there been any obvious degradation of the tractor's hydraulic capabilities. Every thing seemed to work fine, and still does -- although I have been carefull to keep the RPMs down until the machine warmed up.
Due to circumstances, the machine has sat unused since the fall, and I have just now had a chance to look into this. Google has revealed not a single parallel to what I have experienced -- for any brand of tractor. Specifically, I could find no mention of an abnormal hydraulic whine being eliminated by placing a load on the system.
After looking at the diagrams in the service manual, it seemed like the most likely culprit would be a malfunctioning relief valve. If loading the hydraulic system hadn't stopped the whine, I would have suspected the hydraulic filter (cavitation due to insufficient intake flow at the pump), but in my mind, I couldn't make the connection to a faulty filter.
Still, the filter was relatively easy to change, and I had one on hand (genuine Branson), so I changed it. BTW, it is possible to change the filter without draining the fluid first. Just be prepared for a bit of a mess. /forums/images/graemlins/tongue.gif
Once I screwed the Branson filter on -- and cleaned up a bit -- I fired her back up and the whine was completely gone. /forums/images/graemlins/crazy.gif
So much for my theories. In any event, I don't know if the Napa filter was defective, or if the Napa 1202 is inherently incompatible, but I'll be visiting my friendly dealer and buying nothing but Branson hydraulic filters from now on .
Just thought I'd pass this little experience on.
When the ambient temperature dropped below approximately 70F, I started getting a loud hydraulic whine from the front of the machine. When I say ambient, I am referring to the outside air temperature at the time the machine was first started that particular day, and by extension the temperature of the hydraulic fluid after the machine had been sitting overnight or longer.
The whine wasn't pure, but had a rattle quality to it, and it was sensitive to both engine RPM and temperature. There was no whine below about 1500 RPM when the temperature was about 70F. As the temperature dropped, the whine started at lower and lower RPMs, until it was present at all speeds when the temperature was about 50F or below. Operating the tractor long enough (at RPMs below the threshold of the whine) eventually warmed the hydraulic fluid enough that it ceased for the day, even at PTO speed.
The whine only occurred when there was absolutely no load on the hydraulic system. As soon as the bucket was raised, empty or full, and however slowly, or if the 3PH was raised, the whine stopped instantly. It never tapered off or came on gradually. It was either there or not. At no time has there been any obvious degradation of the tractor's hydraulic capabilities. Every thing seemed to work fine, and still does -- although I have been carefull to keep the RPMs down until the machine warmed up.
Due to circumstances, the machine has sat unused since the fall, and I have just now had a chance to look into this. Google has revealed not a single parallel to what I have experienced -- for any brand of tractor. Specifically, I could find no mention of an abnormal hydraulic whine being eliminated by placing a load on the system.
After looking at the diagrams in the service manual, it seemed like the most likely culprit would be a malfunctioning relief valve. If loading the hydraulic system hadn't stopped the whine, I would have suspected the hydraulic filter (cavitation due to insufficient intake flow at the pump), but in my mind, I couldn't make the connection to a faulty filter.
Still, the filter was relatively easy to change, and I had one on hand (genuine Branson), so I changed it. BTW, it is possible to change the filter without draining the fluid first. Just be prepared for a bit of a mess. /forums/images/graemlins/tongue.gif
Once I screwed the Branson filter on -- and cleaned up a bit -- I fired her back up and the whine was completely gone. /forums/images/graemlins/crazy.gif
So much for my theories. In any event, I don't know if the Napa filter was defective, or if the Napa 1202 is inherently incompatible, but I'll be visiting my friendly dealer and buying nothing but Branson hydraulic filters from now on .
Just thought I'd pass this little experience on.
