HELP troubleshooting the hydrauilc squeal

[dieselfuelonly]

Hi all,

I posted a while back about having some issues with my hydraulics "squealing" when I tried to lift heavy items...

I ended up with the feeling that it was just normal since my tractor is pretty small.

But recently I've noticed it more, and am thinking, no, it shouldn't be like this. I've been doing some reading here, and from what I've gathered, I should be able to lift stuff with my 3pt to the point that the front end gets REALLY light, and possibly off the ground, even with the little lead & concrete ammo box bolted to the front of my tractor.

When I am carrying the bush hog, when I hit a bump in the ground, I get a "squeak" when the weight of the hog "shocks" downwards, and I purchased a 4' box blade today, and got quite a bit of squealing when lifting the box blade when it had some material inside of it. This is the same sound I get when you lift the 3pt all the way, and keep trying to lift it up but it can't go any further.

I know thats not normal.

Heres what I know:

The noise is coming from under the seat. I changed the hydraulic fluid less than 5 hours ago, using JD 303 spec oil which is what my tractor is supposed to run. There are no leaks. Level is good. Filter is squeaky clean. The "stop" valve is WIDE open. The flow control valve is open to my speed liking.

Anyone got some ideas on where I should start?

Like I said, I KNOW its coming from somewhere under the seat, and not the pump, so its for sure not starving for fluid. Under lightly loaded conditions using my lighter implements, it works just fine.

Some help would be greatly appreciated!

Dennis

 

[MJPetersen]

Hi Dennis,

It is the relief valve saying that it does not want to do more! It is adjustable--BUT NOT without proper gauge so that you KNOW what is going on. I think that most of our Yanmars have a relief setting of 1950 psi.

I have one question though--you say "

The flow control valve is open to my speed liking.

" Is this the valve that controls the speed of drop? Does changing it, change the point when the "squeal" starts? Ok that was 2 questions.

Mike

 

[dieselfuelonly]

Mike - thanks for the response!

Yes, I do mean the valve down below by the right fender that controls how fast the hitch raises/lowers. So far I've played with it a bit, and it does not seem to change the point at which the "squealing" occurs.

Thanks!

Dennis

 

[kenmac]

Don't you have any adjustment. From yhat I'am understanding. Your piston is moving too far inside the lift system. Mine got out of adjudtment & would make this noise. Like it's trying to lift higher than it is designed to lift

 

[dieselfuelonly]

I don't think the piston is out of adjustment, because it doesn't have any problem lifting lighter loads at all. Its as smooth as can be. And since it seems to be making the EXACT same noise when trying to lift a heavier load as when the hitch is all the way up and cannot go any further (but still trying to go further), I'm thinking something is up with the relief valve. I'm going to try to get a hydraulic pressure gauge today. Can someone advise me how to hook it up, and what is the proper way to use to gauge to test the pressure?

Thanks!

 

[dfkrug]

DIESEL:

The easiest way to use a pressure guage is to block the flow in a work
port with it. I often use a loader cylinder hose connection at the cyl.
It is good to have a supply of caps and plugs to keep oil from leaking
out of open connections. When the guage is attached to the hose,
operate the FEL valve to relief. Note that the other cyl in parallel
with the one you have disconnected will need to fully travel to the
end before the RV operates. That is another reason to cap off open
cyl connections. The RV on your FEL valve is in parallel with the one
on your tractor so the one with the lowest setting will operate (squeal).

On many tractors the 3PT lift control is not properly limited so it sends
the implement pump circuit into relief at the highest lever position. You
should limit the travel of that lever with the adjustable stop, usually
provided.

 

[kenmac]

I don't think the piston is out of adjustment, because it doesn't have any problem lifting lighter loads at all. Its as smooth as can be. And since it seems to be making the EXACT same noise when trying to lift a heavier load as when the hitch is all the way up and cannot go any further (but still trying to go further), I'm thinking something is up with the relief valve. I'm going to try to get a hydraulic pressure gauge today. Can someone advise me how to hook it up, and what is the proper way to use to gauge to test the pressure?

Thanks!

Ok, Mine was making this noise but, I had the leaver all the way up & the bush hog or box blade was all the way up & the lift was still trying to go higher. This is the only time mine has made this noise. I adjusted the lift point & haven't had any more problems