Chattering in hydraulic lines on 7520

[SpiderD65]

Iv'e lurked on this forum since my purchase of a two wheel drive 7520 with a FEL in August 07, but this is my first post. I need help. The rear hydraulic outlets are controlled by levers that have a raise position, lower position, and then a float position. When I move the lever from lower to float I get a chattering noise in the hydraulic lines coming into the stalk for the FEL. I first noticed this while using a batwing mower.

The tractor just came back from my dealer where it has been for about three weeks for this problem. The service manager tells me they have changed the hydraulic filter, cleaned the screen, raised and lowered the FEL numerous times to clear air in system, if any, cleaned and abraded fittings and double clamped them, ran pressure tests on hydraulic pump and probably other tests that escape my mind. He stated that the Mahindra rep that he was working with said that all 7520's make a chattering noise when hydraulic lines are not hooked up to the outlets, but no chattering occurs when lines are hooked up.

My question is this, do any of you that own a 7520 ever notice a chattering in your hydraulics when moving your lever to the float position? Does any chatter occur with or without hydraulic lines plugged into the rear outlets? Thanks in advance for any assistance.

 

[DavesTractor]

If you are using the remote levers with nothing hooked up to the remotes, the tractor must bypass the flow. The 7520 has a large pump and it must be bypassing some of the flow at the loader pressure relief. It is a safety so if someone does use the levers with nothing hooked up it won't break anything. However, there is no reason to touch those levers unless they are hooked to something....so stop doing that and your noise, which is normal, will go away.

 

[SpiderD65]

Dave, Thanks for the info. it does chatter when an implement is not hooked up, but I have only tried that to determine where the noise is coming from. I sent the tractor back to the dealer for several minor poblems as well. What brought my attention to the problem is when I was mowing with my batwing mower and I would raise or lower the mower due to terrain. Sometimes I would push the lever to far forward and go past the down position and the chattering would occur. I don't think it should be doing that with the hydraulics hooked up. Any thoughts?

Bob

 

[MtnViewRanch]

What brought my attention to the problem is when I was mowing with my batwing mower and I would raise or lower the mower due to terrain. Sometimes I would push the lever to far forward and go past the down position and the chattering would occur. I don't think it should be doing that with the hydraulics hooked up. Any thoughts?
Bob

Bob, just to clarifie, when you push the lever forward into the float position, does the chattering occur only while the batwing is falling down to its lowest position and then stop? Or does it continue to chatter if you were to leave it in the float position?

 

[SpiderD65]

Brian,

No chattering occurs when in the float position, just as you move from the down position to float. I'm not noticing the chatter as much since the tractor came back from the dealer.

Bob

 

[MtnViewRanch]

Brian,

No chattering occurs when in the float position, just as you move from the down position to float. I'm not noticing the chatter as much since the tractor came back from the dealer.
Bob

Bob, so it only chatters for the fraction of a second that it takes to go from down to float? By chance is the batwing new? How many times have the hydraulics been cycled? I'm wondering if you have air in the system due to the new hydraulics on the batwing. Don't know, just grasping here. Doesn't make sense to chatter unless air is in system or maybe if the valve ports are not aligned properly. Weird that it only does it between valve ports at that position.

 

[SpiderD65]

Brian,

The batwing was purchased new in 06 and has been used with my Case MX110 probably 15 times with no issues.

Bob

 

[MtnViewRanch]

Brian,
The batwing was purchased new in 06 and has been used with my Case MX110 probably 15 times with no issues.
Bob

OK, no problem with the batwing then, so is it just that split second between down position and float that it is chattering?

 

[SpiderD65]

Brian,

Yes. However, when I raise and lower the batwing I don't normally go to float position. I get into the chattering situation when I inadvertently go past the lower position when lowering the mower. The wings are allways operated in float position.

Does your 7520 ever chatter?

Thanks'

Bob

 

[MtnViewRanch]

Brian,
Does your 7520 ever chatter?
Thanks'
Bob

Bob, as far as with the rear remotes, never have had any problems what so ever. But so far have only used them for my top"n"tilt setup. I have had the loader shudder before, but that was due to low fluid level. As long as the fluid level is above the add mark I've not had any hydraulic problems of any kind. The only annoying hydraulic related noise that I have is the relief valve from the loader circuit and that depends on the temperature.

I'm thinking that your chattering has to do with the weight of the wings while being lowered and for some reason that is causing the chattering that your getting when the valve is between each port. I just cannot think of anything else it would be. See if it gets any better soon. Sorry that I don't have a definite answer for you. Does the Case have the same sort of valving?

Gotta go now, I'll check back later.