JD 400cx loader hydraulic issue on 4120 tractor

[Prodigitalgear]

I have a 2006 JD 4120 with 400cx loader. I have fork and bucket attachments. With either, if I have a load or not, the tilt part will not hold. In other words I can lift the forks all the way up and leave the machine idling for 5 min. The lift stays the same, but it won't hold the tilt. It creeps down. We notified the JD dealer when we bought it and they said this was normal. With my JD skid steer I can leave the forks up with a load on it, and it will hold. Any ideas?

 

[Belarus420]

if you dont have any visible leaks (rams,connections hoses etc) its leaking back from your manifold and going back to your resovoir

 

[AKfish]

I have a 2006 JD 4120 with 400cx loader. I have fork and bucket attachments. With either, if I have a load or not, the tilt part will not hold. In other words I can lift the forks all the way up and leave the machine idling for 5 min. The lift stays the same, but it won't hold the tilt. It creeps down. We notified the JD dealer when we bought it and they said this was normal. With my JD skid steer I can leave the forks up with a load on it, and it will hold. Any ideas?

Welcome to TBN, Prodigitalgear. Cylinder leakdown is "normal" but there are reasonable "time outs" when the leakdown rate is excessive and the cylinder should be re-built. The JD Technical Repair Manual contains that information - which the dealer uses to determine if the cylinder(s) should be either replaced or re-built.

Time the leakdown. Talk with your dealer (better yet, the shop foreman) and ask them if the "time out" for your curl cylinders is excessive or within the normal "range".

AKfish

 

[Prodigitalgear]

Well..I told them about it when it was brand new and all they told me was....that it was normal. My brothers New Holland doesn't do it nor does my JD skid steer. Maybe it's a design. BUT....have other problems now when I tried to budge a stump. I went up and over a stump after cutting what I thought was all the roots all the way around. It wasn't huge..maybe a 12" tree. I tilted the blade all the way down, and tried popping the stump as I backed up. Well..something popped all right. Now my tilt doesn't work. One side is.but one side isn't. The lift is fine but when I left the bucket it will just tilt all the way down. If I try to move it back...it appears the right side is starting to come in but the left isn't. The piston doesn't appear warped or anything. Any ideas? I dropped the bucket and am about to pull the piston but I don't even know what I'd be looking for. Any assistance would be appreciated...OH..I checked all the hoses and hydraulic piping to the lift/tilt control and there was nothing leaking or anything like that. Thanks in advance. Andy

 

[arlen4720]

Well..I told them about it when it was brand new and all they told me was....that it was normal. My brothers New Holland doesn't do it nor does my JD skid steer. Maybe it's a design. BUT....have other problems now when I tried to budge a stump. I went up and over a stump after cutting what I thought was all the roots all the way around. It wasn't huge..maybe a 12" tree. I tilted the blade all the way down, and tried popping the stump as I backed up. Well..something popped all right. Now my tilt doesn't work. One side is.but one side isn't. The lift is fine but when I left the bucket it will just tilt all the way down. If I try to move it back...it appears the right side is starting to come in but the left isn't. The piston doesn't appear warped or anything. Any ideas? I dropped the bucket and am about to pull the piston but I don't even know what I'd be looking for. Any assistance would be appreciated...OH..I checked all the hoses and hydraulic piping to the lift/tilt control and there was nothing leaking or anything like that. Thanks in advance. Andy

Well, it could be a blessing in disguise...It sounds like the seals on the "puck" blew out. Maybe they were leaking by a little before. Look at it as a "stress test".
Your dealer will fix it now.

Here is a document that has the Max allowable leakdown rates for JD loaders. Your curl should be a max of 3.5 inches per hour. I think the max rates still suck.
My 400cx is pretty good (205 hours) for now.

 

[Prodigitalgear]

Arien4720...this is way out of warranty since I bought it in 2006. It a "puck" something I can replace myself?
thanks
andy
PS- thanks for the chart. My bucket curled 3.5" in 15 minutes!

 

[arlen4720]

Arien4720...this is way out of warranty since I bought it in 2006. It a "puck" something I can replace myself?
thanks
andy
PS- thanks for the chart. My bucket curled 3.5" in 15 minutes!

Yes, a cylinder rebuild kit should get you going. There is a cap (puck) on the rear of the cylinder rod with seals. Of course, when you tear it down, there could be some other damage as well, but I doubt it. Has this leakage gotten worse over time?

 

[Prodigitalgear]

Yes, a cylinder rebuild kit should get you going. There is a cap (puck) on the rear of the cylinder rod with seals. Of course, when you tear it down, there could be some other damage as well, but I doubt it. Has this leakage gotten worse over time?

Yes...but marginally. Thanks for your assistance. I have the owners manual for the 400x loader, but not the service manual. I'll search the net now so I can see what I'm getting into! Thanks.....