Hydraulic Squeal

[tractor kid]

I have a 87' Kubota B7200 w/front loader. It started this horrable sqeal in the hydraulics yesterday. I had to keep moving the bucket up and down or tilting it all the time to keep the squeal from driving me nuts. I have plenty of hydraulic fluid. I shut the tractor off for about 5 minutes, but was still squealing away after I restarted it. Could it be as simple as air in the lines?? If so any one know how to bleed them. Many Thanks. TK

[RobJ]

The system should be self bleeding because of the open run back to the rear end. Might be a pump going out, the sound is going away when the pump is under a load.

Is the motion of the fel and lift arms smooth?

Bout all I can offer...good luck,
Rob

[Soundguy]

Could be pump cavitation from an air leak.. but the sound going away when under load is odd.

Did you check all belts.. to see if something is slipping?

Are your loader controlls centering correctly. I gues if the spool was stuck.. it may be making the loader relief open if the oil could not get to sump.. but when you are moving the laoder.. oil is going to a cyl.. and not deadheading against a relief valve.

I think I might put the relief line ( if seperate ) over into a bucket and see if the valve is in constant relief...

keep us posted...

Soundguy

[tractor kid]

RobJ- Yes the fel and bucket will move smoothly with no problem. The bucket does slowly tilt down with no load on/in it. Don't know if that is part of the reason for the squealing. The squealing doesn't happen all the time, just on ocation??? Thanks TK

[dfkrug]

Are your loader controlls centering correctly. I gues if the spool was stuck.. it may be making the loader relief open if the oil could not get to sump.. but when you are moving the laoder.. oil is going to a cyl.. and not deadheading against a relief valve.

This is my thought, too.

Sometimes it is an embarassingly simple thing, such as: bumping the
3-pt lift lever up to the relief position by accident. Or a quick coupler
not fully seated.

[normde2001]

Does it have an internal fluid pickup screen that needs to be cleaned, or a servicing stop valve that might be partly closed?