4320 Hydraulic Noise - Found the line now what

MaverickM23 · Oct 10, 2016

Posted on here last week about my 4320 making a hydraulic noise under the dash. Took the hood of and checked all the lines for rubbing and found nothing. Went and mowed hay with it but left the cowl off so I could feel when it was making noise to see where it was coming from. It happens when I idle the tractor down to around 1200 rpms and it is coming from the large line that goes into the bottom of the pressure control housing. I can feel it making the noise and when I pull on the line it will kind of go away but as soon as I give it throttle it goes away. And it is kind of like a slithering sound kind of hard to describe any ideas? I have attached a picture and it is line number 6 that I am referring to.

Ragnarok · Oct 10, 2016

Pressure line to the rockshaft...better check the line clamps depicted in the picture...maybe gone or worn-out....will wear a hole in the pipe and make a 2350psi mess!

Tx Jim · Oct 10, 2016

Line(key 6) supplies oil to 3 pt & scv's. I'll guess noise is a leaking inlet or outlet valve in frt hyd pump or possibly stroke control valve not seating correctly. Could also be faulty pressure control valve(key 7).

MaverickM23 · Oct 10, 2016

So how do I go about testing to see what it could be. I will check the line clamp when I get home tonight to make sure it is on and tight. The tractor has 6100 hours on it.

Ragnarok · Oct 10, 2016

Stick a good 5000psi gage in on of the scv outlets and just see if the pressure is 'jumpy'...if the needle is a blur(not reasonably steady)...maybe a pump issue

Those pressure lines do tend to vibrate and crack or wear through especially if the clamps are gone or bad...I've replace quite a few on newer series tractors

MaverickM23 · Oct 10, 2016

I did that and it slowly and steadily climbs right to 2000 and stays. I have read it is suppossed to be 2250 should I try to increase it?

Tx Jim · Oct 10, 2016

You can increase stand-by to 2250 but it would surprise me if "your noise" went away

Bob · Oct 10, 2016

I've seen sever that have been replaced by a hose. Wonder how much that helped the noise/vibration issue?

tim s · Oct 10, 2016

Yes check your clamps on the line,, I have seen a chipped outlet valve cause noise like this,, sorta like a burnt engine valve popping back through the carburetor.. when they are chipped it lets that piston "spuder"...you would need to disassemble the pump to prove this theory..and as we have talked about this before an old pump with a lot of hours on it may well be better to replace...

MaverickM23 · Oct 10, 2016

I will check the clamp problem is this is a cab tractor
so I might have some trouble getting to it. I will post
back when I find it

MaverickM23 · Oct 10, 2016

The one thing I forgot to add was that if the tractor has sat for a while when it starts the three point arms come up slowly and hesitantly making lots of noise not sure if that indicates anything or not

Tx Jim · Oct 11, 2016

(quoted from post at 22:29:46 10/10/16) The one thing I forgot to add was that if the tractor has sat for a while when it starts the three point arms come up slowly and hesitantly making lots of noise not sure if that indicates anything or not

3 pt chattering & raising slowly after tractor has sat idle for a while is caused by hyd oil bleeding back to sump. This can be helped by installing a functional check valve in supply line.

MaverickM23 · Oct 12, 2016

Is there already a check valve in it that might have failed or do I need to put one in it. I got under the tractor last nite but could not see the clamp like I said its a cab tractor so I am going to have to
remove some stuff to get to it. I like the idea of replacing it with a rubber hose, anyone else ever done this?

MaverickM23 · Oct 13, 2016

So last nite while looking for the clamp I played around with the speed levers on the SCV's to see if that would make a difference. I turned them both up to fast and didn't notice any difference operating the
mower up and down or in and out, what did change was that when I had it on fast and I went to raise the mower it raised very very slow. It would come down alright but raising took forever. So I moved it back
in the middle and it raised and lowered fine. Wasn't sure if this could be tied into my noise problem or not.

Tx Jim · Oct 13, 2016

(quoted from post at 07:53:24 10/13/16) So last nite while looking for the clamp I played around with the speed levers on the SCV's to see if that would make a difference. I turned them both up to fast and didn't notice any difference operating the
mower up and down or in and out, what did change was that when I had it on fast and I went to raise the mower it raised very very slow. It would come down alright but raising took forever. So I moved it back
in the middle and it raised and lowered fine. Wasn't sure if this could be tied into my noise problem or not.

It's possible scv flow control valve has been installed incorrectly 180°

MaverickM23 · Oct 13, 2016

Is that what is inside item 7 in the drawing? Sorry for all the questions hydraulics troubleshooting is new to me, but like I said this noise drives me nuts

Tx Jim · Oct 13, 2016

SCV flow control valve & handle is outlined in blue which controls cylinder speed of operation.

tim s · Oct 13, 2016

The handle could be 180% off when it was installed...I'm still thinking you have a leaking,chipped outlet valve..this will send extra vibration through out the system.

MaverickM23 · Oct 13, 2016

So it sounds like the main pump should be pulled so I can check it all out or possibly replace it. Is the valve on the back hard to remove and rotate so that it operates correctly?

Tx Jim · Oct 13, 2016

(quoted from post at 12:47:57 10/13/16) Is the valve on the back hard to remove and rotate so that it operates correctly?

Plate that holds flow control valve isn't difficult to R&R and rotate flow control valve. I'd advise to get new quad rings and tiny o-ring.

MaverickM23 · Oct 14, 2016

So would it be possible to remove pump to check the outlet valve and if one is chipped replace it and be good to go without buying a new pump? Cheapest I found a reman pump for is 825

MaverickM23 · Oct 14, 2016

Alright thanks I will get some o rings and try to fix that. Think I should try to pull the pump to look at the outlet valves?

tim s · Oct 14, 2016

Yes you can visually see if they are chipped and they are replaceable,,don't buy a reman pump "New" after market ones are available for $8-900,, my thought is that is the better way to go..

4320 Hydraulic Noise - Found the line now what

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