Hydraulic problem

Degolyerent · Jul 19, 2011

I have a MX4700 DT it has 370 hours it just started making a hydraulic bypass type noise when I lift the three point hitch all the way to the top
The noise is the same as when you lift your FEL to the top and don't release the lever
I had a new hydraulic filter so I put it on immediately but it still makes same noise
The tractor is still under warranty but I am curious as to what the problem may be
It calls for hydraulic oil change at 400 hours

J_J · Jul 19, 2011

When you raise the 3pt to the max, the relief will go off and make a sound. That is normal.

The fluid through the system has to go somewhere, with the piston at max lift.

SPYDERLK · Jul 19, 2011

If you set the lever just short of max height it doesnt bypass, right? It sounds like youre calling for a higher position than the 3ph can mechanically reach. My 2 Kubs with position control have an adjustable stop at the top portion of the control lever travel to allow setting it to stop short of calling for a height that hits the internal mechanical limit of the rocker shaft.
larry

Degolyerent · Jul 20, 2011

Thanks, something has happened with the adjustable stop I guess, it must be visible from under side of tractor. I did not realize that it has a adjustable stop for the up position. I know it has the adjustable knob to stop it in the down position

Leejohn · Jul 20, 2011

Check your feed back lever adjustment. See if the nut have backed out.

Degolyerent · Jul 20, 2011

I will check that out when I have a chance again, I posted last night without looking at tractor and as far as the upper stop goes it is in same position as always, so I will check to see if nut on lever has backed out, I appreciate your help with this situation
Thanks again, TBN rules!

SPYDERLK · Jul 21, 2011

Degolyerent said:
I will check that out when I have a chance again, I posted last night without looking at tractor and as far as the upper stop goes it is in same position as always, so I will check to see if nut on lever has backed out, I appreciate your help with this situation
Thanks again, TBN rules!

Try not going quite all the way to the stop. Does it still do it?? We have ours set pretty critical at the limit and it does it sometimes if we just slap the lever all the way up. It may not be the same as your issue, but sounds like.
larry

Degolyerent · Jul 21, 2011

The upper stop is not adjustable, and if I stop short of it it does not make the noise, I put a bolt in front of the stop to give it something to 'stop' to
What I don't understand is what could have changed, everything is tight as far as the lever goes, all seems well otherwise
With my new stop in place it does not make the noise and it goes very close to all the way up

J_J · Jul 21, 2011

If you installed a hyd gage in the system, you can monitor the pressure, and use the gage to trouble shoot your system. It would tell you exactly if any valve is in relief, and allow you to set the PRV when necessary. .

Leejohn · Jul 21, 2011

Degolyerent
The lever you move up and down is noi what I'm talking about. It's called a feed back lever, look on the left side of the main lift arms (some have them on the right but yours should be on the left) and you well see a lever and rod with a adjusting nut and jam nut. See if everything is ok there. You should be able to ajust and the arms max out the same time the hand lever hits it stop.