My friend mowed some brush with his new Deere 333E CTL and new brush cutter for me the other day. When he stops the mower it makes a terrible (to my ears) noise, like a shuddering screech down to stopped speed. It just doesn't sound right to me and he has no clue, just says it's always done it. he's probably got 50 hours on the ctl /mower and he's already been through a hydraulic motor on the mower. Anyone with same/similar setup can comment on this issue? The noise comes from the CTL not the mower and it stops in about 3 seconds.
My brush cutter (Brush Monster) make a loud noise when I stop the cutter. It always has. I assume it is the bypass valve opening and closing as the momentum of the cutter turns the motor into a pump.
Spot on with the only correction being "crossover relief valve".
X2 mine does as well..
Thanks guys.
I have seen some of these brush cutters without a cross over relief and the noise you hear is the fluid dead heading inside the motor as the momentum turns it from the cutter side. This can be eliminated with a simple check valve plumbed in. The check valve remains closed when cutting and opens to create a loop when the main valve is closed. This will eliminate the noise and increase motor life. I have done this to several mowers. I will post a diagram if anyone is interested.
Sitting here watching it rain, so I will post the diagram either way.
Thanks for posting the diagram. What if the motor runs in both directions, would you plumb it the same way?
A single direction motor can be done with check valve. A bi-directional motor can't be set up with check valves, they require using a crossover relief valve.
Yes, a cross relief valve would be necessary for a bi- directional application ; it would have to be set above system pressure to from blowing over in a stall situation which happens often in a brush mower. With a mower or a grinder for that matter being made to cut in one direction, it seams reversing rotation would be only used for clearing the cutter of a clog. Is this why both directions would be important to the operation of the mower? I seem to recall the machines I worked on only had a switch to turn the high flow on , in one direction only. I know for a fact the tigercat mulchers I have worked on do not reverse rotor hydraulically.
According to mfg site it already has a crossover relief... so, maybe that's where the noise is coming from?
I just have a Bradco brush mower, it will run in both directions, it has double sided blades. I use one direction for rough woody material and the other direction for field mowing.
I have not seen a mower set up in such a way. That is why I try not to make definitive statements. When using the bi-directional motor is the mower hooked to the same hoses as the grapple would be? So I can be activated either was, or must the hoses be switched to change direction?
Reversing the cutter is the same as opening and closing the control in different directions as you do to open and close your grapple. I assume on a high flow machine you would hook it up to different hydraulic ports but my cutter and grapple hook up to the same connectors. The rotating thumb switch on the joystick controls the aux hydraulic. Push it up, flow is one direction, pull it down, flow is the opposite. Ken
Since you use the same function for the grapple and mower, is it possible you have a cly spool rather than a motor spool. A motor spool would have the work ports open to crank in neutral allowing the motor to freewheel, a cly spool would be closed to tank in neutral and would likely cause a noise in the valve when closed.
To my knowledge all CTL and skid auxiliaries are closed center or tandem spools for use with cylinders, kinda have to be.
I have never seen a motor spool on a SS or CTL. With the multi functions of the machine and the use either fixed or variable volume pumps a motor spool would be unusal. to use with attachments using cylinders each attachment would need either dual pilot operated check valves or dual counterbalance valves to hold a load (keep the grapple closed or open).
So it seems the only option for a bi-directional mower is to hear the noise.
If you wanted to go to the trouble you could install some additional valving on the mower to give you soft starts and stops. If things are matched and sized right it's probably not worth the expense and trouble.
per mfg, noise is normal. Thanks for replies.
Did you ask them if all of their mowers lose a motor during warranty? Just sayin'....
Ha, good one! They say the noise is coming from the relief block.