Hydraulic noise L4330

[Gerald]

Hello to All,
I've be away from TBN for a while, too much work.
Now I am semi retired, more time for the tractors, I hope!

Now for a question I hope someone can help me with. On two
other tractors, both 3010s I installed a hydraulic top link.
They both worked fine. Last weekend I finally got all the parts
together to put one on my new 4330. It works good but has a
loud noise, groan, scream that is the loudest at about 1500 RPMs.
Seems like you can feel it in the line that is the output
from the valve. On all three I used a prince RD-5000 series
single spool valve with powerbeyond. The Tap or block I used
on the tractor was from kubota.
It works perfect but the noise worries me.
Anyone have an idea whats causing the noise?
Thanks, Gerald

 

[nailerguy]

Let me start by saying that I am not familiar with the valve that you are using, but that said, a noise in the hydraulic system as you have described it is usually a high pressure bypass as in a small orifice, built into the hydraulic top link to control the speed of extension or retraction, or a pressure relief valve that is possibly set to low for the tractors hydraulic output pressure or possibly (but not probably as you have done this twice before),a simple plumbing error.

Most tractors use fixed displacement pumps for the lift system and when the valve is in the nuetral position, the oil is returned to the sump. You did'nt say when the noise was occurring but if everthing is fine (no noise) when the valve is in nuetral then the problem could be caused by the top link.

Try this, move the handle slowly until the top link is barely moving, if there is little or no noise at this position and a lot of noise at the full open position, then there could be some kind of orifice built into the top link that prevents it from taking all of the oil that the tractor is sending to it.

The remaining oil has to go somewhere or the pump would make pressure until it failed or it stalled the tractor./forums/images/graemlins/shocked.gif This is where the pressure relief comes in. The excess oil is bled out of the system and back into the tractor at a pressure which is set just below the pump capacity. This way the pump and the tractor do not suffer any damage.

However if the pump is continuosly pumping oil across the relief valve, heat will quickly build in the oil and when it gets above @160 degrees Fahrenheit, standard hydraulic oil will begin to break down and that is when real damage can occur./forums/images/graemlins/frown.gif

Good luck in finding your noise and fixing the problem and one more thing that just popped into my head, does'nt the 4330 have a larger capacity pump (more flow) than the 3010?/forums/images/graemlins/wink.gif

 

[_RaT_]

The pump as I understand first delivers fluid straight back to the 3 pt hitch and from there is sent to the loader. The relief for the hydraulic's is also back there I am told. I have yet to actually dig into mine and do a thorough investigation but plan to as I want to check the relief pressure on occasion. The L30 series cuts out at about 2700 PSI. The high pitch sound sure sounds like a pressure relief issue and a good investigation is needed as dead heading any hydraulic pressure will destroy the pump. While I doubt this to be your case, I would want to be sure that you are bypassing enough. You mentioned you came off the Kubota supplied hydraulic tap. Is this the block of aluminum that has 4 bolts and 3 taps that attaches under the tractor near the HST pedal?

 

[Gerald]

Thanks for the help nailerguy & Rat,
I found the noise, well 95% of it.
One of the hoses was touching the fender,
acting like a big music box I guess.
Anyway I found something interesting here.

<font color="blue"> Hydraulic Noise</font>

I guess it should be a little louder
with 12 ft. of new hose.

Thanks Again, Gerald /forums/images/graemlins/cool.gif