Hydraulic Pump Noise? How to diagnos? TC-21 New Holland

[Ken M]

I have started to get a very sharp "ping" like noise around engine. Not related to engine rpm. Sounds metalic like a ball bearing bouncing around. Not constant. A random noise. Does not do it with any particular front bucket movement. As best I can determine it may be in (or near) the hydraulic pump. I don't have any experience with these pumps so I don't know how they might fail.

Is there anything else near the pump that might cause this noise? A 1.0L Shibura diesel, 1400 hours. I wonder about removing/ examining inside of filter for metal chips. Would this tell me anything?

Suggestions please. Thanks. ---KenA

 

[TractorTech]

If the sound doesn't change with rpm or hydraulic load, probably not the pump

 

[rScotty]

A hydraulic pump can "cavitate" and make a metallic rattling or pinging noise at low RPM if the hydraulic fluid is way low or has too much air in it. However, that rattle turns into a constant whine at higher RPM.
Since yours doesn't change with RPM and is random with load then it doesn't sound like it is the pump.

The hydraulic pump is a set of gears driven by a gear inside the engine. It's usually very quiet. Even when a pump is old, leaky, and worn out, they still don't tend to make much noise unless it whines from low fluid/air in fluid. And the noise they make usually changes with RPM.

Some use a mechanic's stethoscope or listen to the handle of a long screwdriver to help pinpoint noises....I've not had great luck using either diagnostically, but it sure is interesting how much more you hear that way.

Two things I would do. One is change the oil filter and take the old one apart to look for metal. You can probably do that without changing the oil...though that might be a good thing to do as well.

And the other thing is to check and see if your tractor is one that has a cleanable wire hydraulic "crud" filter in the transmission sump. Those can clog up and cause erratic fluid starvation problems.

 

[Ken M]

A hydraulic pump can "cavitate" and make a metallic rattling or pinging noise at low RPM if the hydraulic fluid is way low or has too much air in it. However, that rattle turns into a constant whine at higher RPM.
Since yours doesn't change with RPM and is random with load then it doesn't sound like it is the pump.

The hydraulic pump is a set of gears driven by a gear inside the engine. It's usually very quiet. Even when a pump is old, leaky, and worn out, they still don't tend to make much noise unless it whines from low fluid/air in fluid. And the noise they make usually changes with RPM.

Some use a mechanic's stethoscope or listen to the handle of a long screwdriver to help pinpoint noises....I've not had great luck using either diagnostically, but it sure is interesting how much more you hear that way.

Two things I would do. One is change the oil filter and take the old one apart to look for metal. You can probably do that without changing the oil...though that might be a good thing to do as well.

And the other thing is to check and see if your tractor is one that has a cleanable wire hydraulic "crud" filter in the transmission sump. Those can clog up and cause erratic fluid starvation problems.

Thank you for this information. I don't run the engine at high rpm so I will try that and listen. I did use a stethoscope and a long tube but it does help me isolate the noise. I will take off filter and tear apart. The fluid was changed two years ago and appears very clear but as you mentioned I will probably replace it also. No crud filter/screen that I know of and I had the tranny apart years ago for a broken gear.

One more thought... Is it possible I have a piece of metal floating around in the oil pan that gets picked and hits a pickup screen? Never had a reason to have the pan off so I don't know that is put together. Hummm... Maybe a strong magnet on the pan would capture it? This would be easy/fast to try. Thanks again.

 

[rScotty]

Thank you for this information. I don't run the engine at high rpm so I will try that and listen. I did use a stethoscope and a long tube but it does help me isolate the noise. I will take off filter and tear apart. The fluid was changed two years ago and appears very clear but as you mentioned I will probably replace it also. No crud filter/screen that I know of and I had the tranny apart years ago for a broken gear.

One more thought... Is it possible I have a piece of metal floating around in the oil pan that gets picked and hits a pickup screen? Never had a reason to have the pan off so I don't know that is put together. Hummm... Maybe a strong magnet on the pan would capture it? This would be easy/fast to try. Thanks again.

I doubt that the pickup stream could lift a piece of metal....but the magnet idea still might be worth a try.
I've bought single magnets from kjmagnetics.com. Neodymium grade 52 are the most powerful magnet type on the general market. But you might want to ask K&J what they think. They seem to thrive on odd questions. My guess is they will want to know the pan material & approx thickness...

Another thought is that the hydraulic pump is usually driven off the camshaft - which runs the length of the engine block and transmits noise everywhere. You could pull the valve cover and just see if something is loose up there. Easy to do, and any problem would be obvious. Often that gasket can be reused with a bit of RTV.
If your motor has a manual compression release, at the same time you can check inside the valve comer that mechanism is set right and the spring still intact. Loose/floppy manual compression releases can make a noise like you describe.
rScotty