Boomer 8N Loader won't lift unless bucket is curled back

[cougarmandan]

So, for the first time in its life, my 2009 New Holland Boomer 8N is having to earn its keep. I am doing some dirt work at my house with some hard clay dirt. Its been acting strange lately. It has 121 hours so far. The 3 point hydraulics work great, not problem there. However, the 250TL loader is having some major hydraulics issues. It started out if you pointed the bucket down and drag it back to spread the dirt, it wouldn't hold the bucket position at all, then it wouldn't lift the bucket at all and would fall straight down if you tried to lift it. If you let the bucket all the way down, it could then be lifted back up. Unrelated, one of the hoses started oozing out of a small crack so I replaced it on the bucket lift but I don't think it is related. Well, progress to "we" kept using it and it has gotten worse. Now, there is almost no lifting the bucket and there is only one way to lift it. if you curl the bucket all the way back while simultaneously lift, it will go up, but its weak. I call it the bucket curl where the bucket hinges on the end. The curl is strong. It will lift the tractor up. Oddly, if you have it curled all the way up, it will lift the bucket up. If you get it up, and stop curling while still lifting up, it will fall down, fast (and very dangerously). I pulled the control valve assembly and carefully disassembled it. I cleaned and cleaned it and put it back together. It doesn't appear to have much wear or filth on it. Other than greasing up the float detents which allow it go into float now, it hasn't changed a thing. I talked to the local dealer who I would say was very helpful and the technician had a little trouble grasping what I was saying, but said I need to get pressure readings on each of the quick connector ports. I have a gauge ordered and in route but it won't be here until next week. Anyways, he said to check the relief valve for a broken spring and make sure all my couplers are seated. I took the couplers off and reseated them. The relief valve is part of the diverter assembly so I took out the plug and cleaned the spring and valve. I did notice what I thought was a chunk of oring or black paint in the female quick coupler, I got it out but it didn't seem to help. Anyone had a similar issue? My thoughts were pull the coupler and make sure there is nothing on the back side (if you can see it) and maybe pull the diverter all the way out (which will be a pain) and see if I can locate any trash inside it. Also, I changed the hydraulic filters yesterday and there is plenty of fluid.

 

[cougarmandan]

Update: I pulled the diverter/relief valve apart and cleaned it. Then reassembled and no change. I also pulled the mid mount control valve off and completely disassembled, cleaned, reassembled and reinstalled. Still no change. I pulled the quick connectors off and checked for debris and everything looks clean seems to be functioning properly. Still doesnt lift but curls stong. Just for kicks I swapped the lift lines for the curl lines and it still does almost the same thing (just a little confusing to control) so that at least tells me that problem is gonna br a restriction on the FEL side and I知 guessing it has something to do with that black chunk of crud I spotted in the connector a couple weeks ago.

 

[bigdeano]

Sounds like a bad piston seal in one of the lift cylinders to me.

 

[cougarmandan]

Well, played with it more and I've never been so confuse. I took the lines loose, but not off, at the cylinders. Thinking I would get an idea if the pressure is getting to them and its flowing some fluid but not enough to spray. I made a video that shows the oddness of the control. Up or down is nothing but curl back plus up or down equals up. I posted the link below. Hopefully it works. Anyways, it is weird stuff.

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[oldnslo]

The video link does not work for me.

Bad piston seal would not let the loader drop with the valve centered.

I am trying to work through a scenario of how the FEL would act if you have a series / parallel valve where the return flow from the lift circuit powers the curl circuit and one of the pistons has came off the rod in one of the lift cylinders.

You stated "If you let the bucket all the way down, it could then be lifted back up." This kind of supports one of the pistons being loose on the rod and lowering the FEL could have possibly pushed the piston back onto the rod temporarily reseating it.

Now if the piston has come completely off and you curl fully the question is could this force the FEL to lift? With one piston off the second lift cylinder would now be in a regenerative condition and could possibly lift the empty loader and would also raise no matter which direction you move your control valve. I do not believe that you could raise the loader fully in this condition though.

This is purely an old mans speculation on what could be happening and pressure testing each function should point towards a valve or cylinder failure.

110% agree this sounds weird...

 

[Dave M7040]

Well, played with it more and I've never been so confuse. I took the lines loose, but not off, at the cylinders. Thinking I would get an idea if the pressure is getting to them and its flowing some fluid but not enough to spray. I made a video that shows the oddness of the control. Up or down is nothing but curl back plus up or down equals up. I posted the link below. Hopefully it works. Anyways, it is weird stuff.

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One guy on this forum was having strange problems. Finally he was asked to take each fitting and hose off the FEL one by one.

On one fitting it was almost completely blocked internally with a steel plate. There was a small hole in the plate to serve as a flow restrictor. He bought fittings at a TSC store and never expected to get a more sophisticated hydraulic fitting like this. Must have been a mistake in ordering or someone did an in store swap.

You need to post some pictures of the FEL valve and where each hose connects to.

Also a complete history. Did the tractor come with a FEL or was it added and by whom.

You really need to invest $30 in a pressure gauge and necessary fitting to be able to plug into your quick couplers to see what is happening.

One hose that has been put in the wrong place like a PB one can drive you crazy.
Can you try again with the video as the previous attempt did not work.
Dave M7040

 

[100 td]

I'm with oldnslo with a broken rod or piston (I have one on my skid-steer to fix!), but a better explanation of the complaint of the 2 main assemblies, i.e. Bucket = Dump or Rollback/curl and Boom = Raise or Lower is needed before I go out on a limb!

 

[Soundguy]

Not exactly the same, but on my NH 7610s, I had a hyds problem. It has 2 remotes. They were the deluxe ones ( 2000 model ). One remote was dead, the other worked fine. However if you held the dead one in a position, and then activated the other remote,the dead one got pressure. Took the valve bank to the dealer, they determined it was a bad pilot circuit. Repair was finding a used valve bank.

Sounds like yours is doing at least something similar.. One part is dead till another part works.

 

[PJ The Kid]

Sounds like you have cylinder seals blown out or a broken rod. Just fixed the same issue with a 310j backhoe, Running both sides of the hydraulics will increase flow in the system and overpower the fault momentarily. The best way to test is to set the rods at mid travel, hold them up with heavy jacks/another machine, tree stumps, etc (any way you can do it safely). cap the lines to the cylinders and remove whatever is holding it. You will get some initial drop of a couple inches from introducing some air into the system but it should hold stead after that initial drop. If it falls completely you will need to have the cylinders re-packed at a minimum.

 

[cougarmandan]

It looks like some of you guys know your hydraulic a lot better than I do. To quickly address some of the questions, it has 129 hours on the tractor. The loader was purchased with the tractor when new and is the special red 250TL that was painted red and stickered to match the tractor. I don't think it was used or anything like that. It is an 09 but I bought it from a dealer 3 years ago with 12 hours and that had to be the last one anywhere that hadn't sold. I hadn't used the lift too hard until I had a hole dug for a basement pour that made a huge pile of clay that needed moved after they were done. Until a couple weeks ago when I replaced the leaking hose, I had never disconnected the quick connects and last night was the first time I have ever removed the loader from the tractor. Pressure gauge finally came in and I went to tractor supply and picked up some fittings to get some readings. 2500 PSI at all quick connectors when circuit was activated. So I probably didn't have it set up correctly because next I put a "T" fitting on for checking pressure along the different points. As soon as I put a T in the line, the pressure reads about 300-400 psi. This is the first clue on what is going on. Anyways, After messing around with it and "checking pressure" at several points, I took off the line and put the gauge on the end of the hose supplying the right cylinder (I was curious if hydraulic hoses swell up and pinch off supply like a rubber brake line does) like and so the gauge terminated the lift line (plugged it off) so I could get a pressure reading. I guess they don't but I was stumped and looking at everything I could think of. When I started it up that time, I pulled back on the joystick and the loader lifted up (with great surprise I might add) with just the left side cylinder connected. Anyways, I pulled the loader off to get to the cylinder attachment points and removed that lift cylinder. There is something inside rattling around so I am guessing that something let loose and that is where the problem lies. I don't have another day off until next week so I'm taking the cylinder to the New Holland dealer and they are going to check it out for me. So, discussing it with a friend, why would it still lift when you had it curled all the way back and the best guess and our conclusion is: no clue, but maybe since both are draining, it caused some pressure to build up allowing the other cylinder to do the lifting. Pure speculation. But I now know that there is a problem in the right lift cylinder and things make a little more sense.