4240 noisy hydraulics, but all is fine

[fdt860]

Hello, yesterday I had a call to look at a 4240 that is making hydraulic noise. Owner put brand new hydraulic pump and new updated pump shaft. The tractor hydraulics are working fine, however the 65 years old owner is complaining that the steering wheel vibrate.

There are some noises in the steering wheel from low idle to 1600 rpm. The vibration happens only if oil is hot. Loosening the steering wheel cap helps it goes away but does not solve it... You can only hear the noise with the door shut: a 4020 owner would not complain.

I put another steering metering valve but this chlanged nothing. The valve came from a 4230 and I had to swap fittings. In the process I managed to put the check valve equipped fitting at the wrong place. On restart, steering was not working, but noise was, completely gone.
I put it back together right and noise is still there.

I noticed the line going to the attenuator on LH side chatters, the one going from attenuator to cab chatters less.

Do you think it is worth trying another attenuator? Do you think that steering block is leaking? Steering is working so wel' I doubt it.
I did not check the priority valve because I had forgotten where it was... But I think she could well be the culprit.

This is a difficult case because Tractors is working very well, nothing hot after hours of use...
Thanks!

 

[Tx Jim]

Although I can't remember ever determining a problem with an attenuator I think that it might be the cause of the noise. Do you have a used
attenuator you could try?

 

[fdt860]

Yes, I can borrow one on a 4650 I have, and I have also a pressure valve and a steering brick.
I have also a huge 500C backhoe noise attenuator that I am not using (yet) . Similar to a 6030 one. I may install it alongside current one.

 

[tim s]

Did you use the same check valve in the metering pump,,I have found a lot of those bad,, but i cant relate the noise your getting,,,does this change any when you apply the brakes ?

 

[fdt860]

Yes I reused same check valve. Noise does not go away with brakes but instantly with steering action. I read later TM1180 manual and it seems that this check valve can be the source of many issues.

 

[tim s]

I find that check valve in bad shape a lot of times,, I keep a couple here on hand,

 

[Ray]

TIM, I need to ask you a question about a 4020 shifter. How can I contact you.Thanks,Ray.

 

[WTW]

The attenuator is nothing more than an empty can that absorbs noise from the hydraulic circuit its connected to. Think of it as a hydraulic muffler. It does not wear out or change condition. It can leak once in a while. It will not generate noise. This is not the problem. DW

 

[fdt860]

Hello, I am back on this topic. Tractor is still noisy after metering valve was disassembled and resealed to change the check valve with a new one.
I made a movie so you may help. The annoyance is very visi le at the end of the movie. help will be greatly appreciated. Thank you!

This occurs o my when tractor has ran some.


https://youtu.be/ovi-HNYl2h8

 

[fdt860]

http://youtu.be/ovi-HNYl2h8

 

[cact34r]

(quoted from post at 08:44:32 10/22/20) http://youtu.be/ovi-HNYl2h8

Does the noise get worse if you push down on the steering column? I have a similar vibration noise on my 8430. Its not there when cold but after the oil gets warm it will start and will cause the steering column to slightly bounce up and down if you push down on it.

 

[fdt860]

Yes, if you pull down the noise gets different, but does not cancel. The load does not disappear with brakes, diff lock, PTO or lifting three point hitch.
I think owner is right about complaining about it. I have anothet bri k that I may try, but I do not like to go blind. I read about a leakage test on the retur' line, could someone plain more about it?

 

[fdt860]

Yes, if you pull down the noise gets different, but does not cancel. The load does not disappear with brakes, diff lock, PTO or lifting three point hitch.
I think owner is right about complaining about it. I have anothet bri k that I may try, but I do not like to go blind. I read about a leakage test on the return line, could someone plain more about it?

 

[cact34r]

Here is a link to the noise mine makes:

https://forums.yesterdaystractors.com/viewtopic.php?t=1454709&highlight=

I have pressure gauges on the clutch circuit and the main system pressure from the manifold under the cab. Clutch pressure is steady and correct in value. The main system pressure reads higher than the manual says it should be: 1900-2000 vs 1700 and has a pulse in it. Based on feedback here I'm thinking a problem in the pump, but I wondered if the higher pressure could cause a relief valve to act strangely.

 

[fdt860]

Update:

I went back to the tractor and installed another brick block.
I disassemble both of them to compare them:

The one on the 4240 had a dab of silicon preventing the inlet check valve to totally close, and the spring inside the big spool was notably shorter. Thanks to the new parts site, I was unable to check, but it was 70mm vs 73.5mm on the other one. I can see that at 79mm the balls on each side of the spool are barely seated.


Conclusion: Noise issue is gone, customer happy, life's good