DF-354 Dongfeng Tractor Hydraulic Problem

[lp15404]

I don't have a diagram of the hydraulics. Yesterday afternoon I bought a new hoses. I plan to completely remove the assembly that holds the screen filter and inspect it for cracks or obstructions. I intend to replace the two hoses that connect the filter assembly to the pumps. I also plan to replace the paper gaskets on the filter assembly with Carquest Supreme Black Gasketing silicon.

I agree that it is probably sucking air into the system or there is some obstruction around the filter assembly. I would think that since the loader and steering are affected, that it must be somewhere around the filter assembly.

 

[Soundguy]

I also plan to replace the paper gaskets on the filter assembly with Carquest Supreme Black Gasketing silicon.
.

Yuck! I'm not a fan of using go in place of paper gaskets....

Soundguy

 

[greg_g]

I also plan to replace the paper gaskets on the filter assembly with Carquest Supreme Black Gasketing silicon.

Bad idea, stick with paper or composite gaskets. When pre-cut gaskets aren't readily available, I always cut my own. The bulk material is cheap, compared with the labor costs involved with cleaning it out after contaminating whatever it's supposed to be sealing. One of my Jinmas came back from warranty maintenace with that blue gasket-in-a-tube evident everywhere. Within a week my hydraulics stopped working. I pulled the suction filter, and found it clogged with carelessly applied blue silicone. In checking further, I found more blue globs in the engine oil and in the transmission/differential sump. The offending dealer later replaced that tractor for me.

//greg//

 

[Soundguy]

In addition to the good info Greg provided about the 'goo' migrating, it also doesn't compress to a uniform thickness. In some applications, gaskets are there not only to seal, but to set bearing preload.. etc.

I also know of many situations where a 'goo'' will cause a blow out where a correct OEM paper gasket would not ( hyds application.. )

Soundguy

 

[lp15404]

OK, I am convinced. I will stick with the paper gaskets. I will have to make my own gaskets. I already made one for fitting the filter assembly to the tractor transmission. I will make one for the back of the filter holder and replace the one that is there now. It looked ok, but I am afraid it might allow air to get into the filter holder.

 

[Soundguy]

Making paper gaskets is a decent project. A razor knife and the appropriate paper or board will be way better than a goo.

In some cases.. a microscopic smear of a specialty goo.. like copepr coat.., etc.. may be used in porous areas where a ho-made paper gasket does not seal as good as a composite one.. etc.

Soundguy

 

[billbill]

hello everyone, I've been reading this discussion for over 30 minutes, and I hope I can be of some help.
First, the problem we are having now is not the problem we started with. The problem occurs only with the nose up, on level ground it's OK. Check your hyd fluid level with dipstick unscrewed. If you think you'll be using your tractor on steep slopes, you will have to overfill your trans.
Second, the original problem was an overpressure, leaking QDs, smoking and heating hydraulic pump. There are many causes for restrictions on these DF tractors. Restricted QDs, 3PH valve(bad UP limit stop adjustment). When the front QD is bad, you get hard starts, a low idle (probable stall), noisy/heating/breaking hyd pump, slow/no loader operation and P/S functions normally. When the rear QD is bad, you get the same symptoms plus erratic FEL operation (reversed controls on joystick ...). If you have a misajusted 3PH valve stop adjustment, push down on the handle !!! It is very easy to get your foot caught in the lever when leaving your seat.

 

[lp15404]

Sorry that I did not have a chance to reply sooner. I have been on vacation.

I completely removed the hydraulic filter assembly and checked it thouroughly for cracks. obstructions and leaks. I did not find any problem there. I replaced the two short hoses that connect the filter assembly to the pipes that go to the hydraulic pumps and rechecked my hydraulic connections. I saw what looked like a small leak on my return hose from the loader controls to the transmission. I had a new hose made up and installed it. There was no change in my symptoms after doing all of the above.

I finally received another gear pump from my dealer and installed it. The loader seems to be working a bit better, but it is still a little erratic on a hill.

As for overfilling the transmission when working on steep hills, how much should I overfill it? Should the fill level be at the fill mark with the dipstick not screwed in. My dealer said it should be screwed all the way down when checking the fluid lever.

I will take a look at the stop adjustment on the 3ph.

 

[greg_g]

Should the fill level be at the fill mark with the dipstick not screwed in.

I say yes. Asian devices that I have owned - those that have threaded dipsticks - included owner's manual instructions to check levels with the threads sitting on the hole, not screwed into it. Whereas these have been primarily Japanese and Korean products, the Chinese do a pretty good job of emulation. As such - even though your manual may not SPECIFICALLY mention how to check levels - I'm pretty sure they do it the Japanese/Korean way.

//greg//

 

[Soundguy]

Experement a bit. ad some oil.. se what it does. When it acts ok.. remark your dipstick.. as long as we are not talking like more than 25% extra oil.. might be good to go.

soundguy

 

[lp15404]

My loader quit working again and now I think that I understand what has been the problem. Thanks to the comments from BILLBILL, I noticed that after the loader failed to operate, I moved the 3ph lift lever and all of a sudden the loader was working again. I had not realized that there was a connection between the 3ph valve and the loader. If I understand the system now, I think that the FEL pump also drives the 3ph lift. It appears to me that fluid from the FEL pump flows through the controls valves for the loader and then it goes through the valve for the 3ph lift control. The lever that controls the 3ph lift normally returns to a neutral position when the lift is raised. It appears that sometimes it is sticking and not going back to the neutral position. I think that when this happens, the fluid from the pump can not return to the reservoir because it is blocked by the 3ph valve and so the loader fails to operate. Does this sound plausible?

 

[3RRL]

Do you have 2 hydraulic pumps or one? Some models have a separate pump for the power steering like mine. That leaves the other pump to run not only the FEL valve but also the 3pt valve and the rear remote valve (if you have).
What's happening, whether or not the pump goes to the loader valve or 3 pt or rear remotes first, is when any valve is open (like it's being used) there is not enough flow capacity to operate the other valves fully. I can "feather" my FEL valve and operate the new grapple but if I open it up full, I can't....just not enough flow. My hydaulic pumps makes 5.6 gals/min I think. I've tried to operate the FEL vlave and the 3pt valve at the same time and no go. I have not tried "feathering" the FEL to see if the 3pt works then? Too hard to do all that at the same time anyway.

 

[lp15404]

My tractor has two hydraulic pumps. It has a CBN-E306 pump for the steering and a CBN-E314 pump for the loader and 3ph.

 

[bluechip]

You can have a situation with a very heavy implement on the 3 point hitch and if the valve is open on the 3 point lift (raise position) back pressure may not let any oil out of the loader, so when you try to raise the loader the oil on the "back side" of the cylinder cang escape, if the pressure is equal, nothing moves. Do you have weight on the 3 point? This can be solved using power beyond so the return line from the loader dumps into the reservoir unimpeded by the 3 point. the power beyond port will be sure that flow is available to the 3 point regardless of loader use, but loader speeds might be reduced by splitting the flow. Even if you don't have weight on the 3 point, if it is trying to lift beyond the stop, the PR valve will be "buzzing" but it may be higher than the PR valve on the loader so again, the loader cant dump oil from the backside of the cylinders. This is an unusual problem as nearly all chinese tractors are plumbed without power beyond.

 

[lp15404]

I have a 6' Bush Hog scraper blade on the rear of the tractor. The blade is pretty heavy. One of the complaints that I have about the tractor is that when I am moving dirt with the blade, I can not raise the blade slowly to gradually level out the dirt. As I start to raise the blade, there is a terrible strain on the engine and the blade does not move until I have pulled back the lever until all of a sudden the blade breaks free and dumps all of the dirt. I am not familiar with the power beyond. I will look into that.

 

[Tractor Nubi]

I purchased a DF-354 LD250 loader and LW-7 (plus cultivator) from China directly. I have only had problems interpreting the instructions and the hydraulics but all is working well..I feel the same at the other more seasoned professionals, that the problem starts with the loader. Newman.com New and Used DEC, Proliant, Cisco is where I got all of my parts from... I think that they are a distributor for a number of companies.

 

[okjohnson]

Hi

Did you happen to resolve your problem with the FEL hydraulics ?

I purchased a task master 432e (which is a Dongfeng) with a loader new , and the loader exhibits the same problem. When on an incline (pointing up hill), it does not lift well, and if it has a load in it, it will not lift at all. It does work great on the level and pointing downhill. I am beginning to think from what I have read here that this is a problem with the Dongfeng tractor, and I probably should not have been so quick to purchase it. I have not heard of Kama , Kioti, John Deere or any other tractors exhibiting this kind of problem.

Also, the fuel gauge says my tank is half full when it is empty.

Also, it is strange that the people who own the Task Master brand name for this tractor do not ever respond.

 

[JohnS]

OKJ, I am not familiar with your tractor or FEL, but would check hydraulic level, and location of the suction pipe within the resivior. If equiped with a tank filter/screen, it maybe severly plugged. Most Jinmas need a good flushing and removal of the original chinese oil. If yours hasn't been done, would recommend that as well.

 

[lp15404]

My biggest problem with the loader was that the 3 point hitch lift lever was sticking and that blocked the hydraulic fluid from the pump from getting back to the reservoir. Once I realized that the 3ph control was the problem, I started making sure that it went back to the neutral position when I released it. As far as not working on a incline, I added more hydraulic fluid and slightly overfilled it.
That seems to help.

 

[okjohnson]

Thanks for the info .
Maybe when I do the 100 hour maintaineance , I can check the filter and hoses. It does get me by the way it is. I will probably question the dealer who sold it to me since he has sold others.

I guess I didn't realize that hydraulics could act this strange.

I only have about 25 hours on it. I do like it so far compared to my 8N . It is real good in the mud , which we have had plenty of in the northeast.

Anyone know if the oil pressure should increase or decrease with increased RPM ?

It goes down on mine and that don't seem to make sense. Perhaps the gauge is wired backward....don't know. May be related to my fuel gauge showing half full when empty.