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