HELP - Kubota M6040 - HELP

[ppaggie]

I just bought a new M6040 and it is making an intermittent noise apparent at idle. Sort of a clunking sounding, with all types of variations; similar to the sound a water pump with a bad bearing makes or a bearing, ball or roller, with just one bad bearing grabbing or rubbing?
I had it to the dealer, and they can't find it. They thought it was in the hydraulic system, air leaking into the system. (but air can't leak in, can it? With the system under pressure, oil would have to come out? ... wouldn't it?

The sound comes and goes, loud and soft, but if you hold onto the hydraulic lines that go to the auxiliary hydraulic fluid cooler mounted in front of the radiator you can feel a distinct vibration in the lines, when ever the sound is heard.

I've listened and listened and it seems to be coming from inside the power steering housing casing attached to the steering column and just above the rear of the engine. This housing is where the power steering hydraulic lines enter and leave. But I've been told by the dealers mechanic that nothing moves inside unless the steering wheel is turned, and then the fluid is just redirected. That nothing is rotating.

Any help would be greatly appreciated !!!

 

[KYErik]

It would be good to first find the definite source of that noise.

Using a long screwdriver handle against your ear, touch the tip of the screwdriver to that power steering casing to verify that it is the source of the noise. A broom handle will work as well, without the broom attached

If a hydraulic pump sucks in air, it will make a rattling type noise. That's how I know when I should have added more fluid to my leaky old backhoe.

 

[ppaggie]

... I did use a 3' metal threaded rod ... which is how I came up with ....

"I've listened and listened and it seems to be coming from inside the power steering housing casing attached to the steering column and just above the rear of the engine. This housing is where the power steering hydraulic lines enter and leave. But I've been told by the dealers mechanic that nothing moves inside unless the steering wheel is turned, and then the fluid is just redirected. That nothing is rotating."

Also, how can the hydraulic pump suck air? ... when the hydraulic system is pressurized on both the flow & return .... ? any opening should have oil being forced out by the pressure.

If air is trapped in the system, the dealer said this could cause the noise.
But they tore everything apart, and put it back, SAME SOUND !!

Thanks

 

[KYErik]

Crack one of those power steering lines loose from the noisy housing a tiny bit and then start the tractor. Watch the "leak" as it makes the noise. If there is air in the fluid, then it will look frothy white as it leaks out, like it has water mixed in it. If it looks clear as it dribbles out, there's no air.

Pehaps a bad pump seal might not let fluid leak out in one direction, but might be able to suck air when there is suction on it (in the other direction).

You could also check your power steering reservoir while its running and making the noise to see if the fluid is a frothy white. This would be easier/less messy than loosening a line.

One more possibility- my backhoe has a hydraulic clutch/torque converter. Under certain situations, there is a spring loaded relief valve that can make a buzzing noise.

Will it make the noise at idle while you move the steering wheel back and forth? What about when you turn the steering wheel until it stops? Can you hear that the pressure relief valve is working? Is the noise still there while doing all this (moving the steering wheel)?

 

[ppaggie]

Hello

Best I can tell is the whole system, power steering, transmission, and hydraulics's all use the same fluid and pump. The dealer took the pump apart and checked everything, including changing the fluid and filters.
The noise stayed exactly the same.

I do have a hydraulic clutch/torque converter, but when I move it around, nothing changes. The power steering, lock to lock, and rotating the steering wheel, has no effect on the sound. I can hear the pressure relief valve working.

If I hold on to the metal hydraulic lines I can feel in them a hit (rub) of metal to metal synchronized with the sound. If while doing this I increase the RPMs I can feel the hitting increase, intermittently, but the noise is drowned out.

It feels and sounds to me like a bad water pump bearing which would allow an impeller to contact the interior casing, periodically. But I listened there, no noise. Also, what about a bad roller, or ball bearing, couldn't this cause this condition. One other thought, a nut or bolt not quite tight, moving in and out, and on rotation contacts the interior of its casing or housing. That's why I thought it was the power steering housing, especially since the noise seems to be coming from there. But the problem with this is nothing is rotating inside unless the wheel is being turned.

So with the noise I'm describing something has to be rotating whenever the motor is running and increasing in speed with the increased RPMs.

Thanks again for your interest and suggestions.

 

[big bubba]

A new tractor under warrantly should be entirely the responsibility of your dealer....you shouldn't have to take the time to troubleshoot. And don't let them give it back to you till you're 100% confident the problem is solved. You may also consider calling the techs at Kubota central and describe the problem, if not only to have it on record as well. You paid big bucks, get the biggest bang out of them. good luck bb

 

[big bubba]

A new tractor under warrantly should be entirely the responsibility of your dealer....you shouldn't have to take the time to troubleshoot. And don't let them give it back to you till you're 100% confident the problem is solved. You may also consider calling the techs at Kubota central and describe the problem, if not only to have it on record as well. You paid big bucks, get the biggest bang out of them. good luck bb

 

[ppaggie]

I absolutely agree with you ..... BUT, .....I don't like the tractor, I love it, and I need it. The noise is intermittent, and only noticeable at idle, .... and now, unless I listen for it .... I don't hear it .... it does seem to be getting quieter. The dealer checked everything, tore apart the pump & replaced a couple of valves. It is on record, and they have checked with their support at Kubota. I keep fooling with things, it has a hydraulic shuttle and it seems if I put the gear shifter in neutral, and move the shuttle the noise stops. The problem is the noise stops on its own, so I'm not sure yet ... but I'll keep trying it. Thanks for you help! I still might do as you suggest. I know I will, if it starts to get worse, instead of better!

 

[big bubba]

Good luck. Yeah, I just bought a 7040...they had to adjust the hyd. shuttle linkage, apparently a common problem on some new machines..so if it seem not to engage fully, that may be the problem. Glad you have good dealer support. bb

 

[Glowplug]

I'd put money on the hydraulic shuttle. Have you brought that up to your dealer? I don't know if it's a serious (engine threatening) or an expected noise. I certainly don't hear it with my tractor. Of course I've been told I don't have the best hearing. Just ask my wife!