Hydraulic bug hunt

[valley]

Greetings, This problem is on a Foton 254 with a ZL-20 FEL. FEL when tractor is first started won't move, when warmer slow, and when nice and warm works good.
I have a couple of thoughts first: On the FEL's valve lower left is an item sticking down. [This is the best shot of it I have now. ] Is that a pressure regulator of some kind? Click to make larger.

 

[valley]

Here is where I'm going! when I turn the wheels to full lock {when cold] the loader begins to move. Full lock must create hydraulic back pressure. Somewhere the oil moving at low or no pressure until the oil is warm. Since the power steering works at all times it has to be in the loader valve, the divider valve or the 3 point! That's what I come up with! What do you think? Richard

 

[Philscbx]

A couple of things need to be looked at.
Take a sample of the oil, and see what it's pour point is like cold.
Sounds like the base weight is too heavy.

Next check the hydraulic filters.

The pressure relief valve maybe damaged from wear.
Check the main, and your FEL control valve.
Pull it out and inspect the ball or poppet and seat.
They can be rebuilt easily.
I've seen the poppet and seat worn out with cut polished grooves like a laser from fine debris.

I'd start with those 2 main items first.

 

[greg_g]

I believe you may be trying to point out a pressure relief valve. But you've been fighting this issue through several threads on more than one forum. Why don't you summarize here what you've done so far? That should help avoid a bunch of redundant questions.

I've seen folks suggest to you before that this is symptomatic of flow restriction, typically caused by thick hydraulic fluid. It's winter. It takes time for the oil to warm up and thin out, to the point where it will pass freely through the restriction points (screens/filters, valves, controllers).

Since the FT254 is of separate-sump design, I believe you were advised to drain/flush/refill with AW32 hydraulic fluid - to clean or replace the suction filter in the sump - then to inspect/clean the valves on the pressure side (priority/loader/lift) if flow is still restricted. How much of that have you accomplished?

//greg//

 

[Diamondpilot]

You cleaned the Priority Valve. You need to change the fluid. This is a common issue with Chinese tractors. You need to clean the system with a flush and service with AW32 non foaming hydro fluid like Greg has suggested.

Chris

 

[RonMar]

Yep, it does sound like too thick of an oil in the hydraulic system. The works better as it warms description is a dead give away. My 254 came with what looked like 30 weight oil in the hydraulic sump. Maybe it was UTF. It had the same oil in the gearbox. Well it is too thin for gearbox oil and too thick for hydraulic fluid. If yours is the same, you need to change all the gearbox and hydraulic oils. My hydraulics work fine in all the temps I encounter where I live with AW32 in the system.

 

[valley]

OK! I've drained the sump,and cleaned the bottom, but have not flushed the system. I extended the suction pickup deeper into the sump. I refilled with Anti wear ISO 32. I now have a suction screen I plan to put in, there was not one and the pickup was only 1 1/2" into the sump. This time I will flush the system. Yes! I did clean up the divider valve.
Then:I went on to do all the things not related to hydraulics you do when you get a tractor new from China,fluids and adjustments, I think they were never done.
Now: I think getting the hydraulics in working well,before converting and changing anything, is in order. I just heard some good information.
I started this thread on the hydraulics because there are other things that can be talked about and information searched without clouding hydraulic repair here. Richard

 

[Frankm]

Hello . My 20Hp Nortrak done the same thing from new , in the summer it works fine , in the winter it is just like yours , i have done all the things there telling you to do , and it is still the same , if you fiend out whats wrong with it please let me know at corvette@velocity.net , Thanks !

 

[valley]

Frank, You got it! If I find the bug I'll stick a pin in it and send it to you. Richard

 

[valley]

One by one as time and weather permit

1. I will, when the weather clears, flush the system and install a Jinma suction strainer and fill with fresh hydraulic 32.
2. Open the FEL Valve and see what it has to say.
3. ?

 

[valley]

Phil, Thanks! I'll looks this over and over. Richard

 

[valley]

Well! Here is how it went: I pulled the plug on the hydraulics, draining out the AW 32 I had filled with after cleaning the sump. It looked like ****, filthy looking. I removed the down spout I had installed when I cleaned the sump, I installed a Jinma Suction Strainer. I filled with diesel oil and as per Rob's suggestion I started the tractor and worked the hydraulics for a good hour. What diesel came out looking like drain oil. I pulled out the suction strainer. It was suprisingly clean. I reinstalled the suction strainer and filled with AW 32. The FEL fuctioned perfectly.
Conclusion: If the FEL fuctions well when cold today I'll have a brandy, sing and thank God. If not I will hunt out a even lower viscosity oil maybe AW 15. Reasoning: I could not have been happier with the way the FEL moved with the diesel oil. With caucious optimism Richard

 

[greg_g]

Conclusion: If the FEL fuctions well when cold today I'll have a brandy, sing and thank God. If not I will hunt out a even lower viscosity oil maybe AW 15.

Don't go overboard here, anything thinner than AW32 is typcially for arctic or sub-arctic conditions. You'll be just fine with AW32 there in Tahoe

//greg//

 

[3RRL]

Richard,
Bravo, looks like you got some good satisfying results.
Flushing all that crap out makes a difference. Glad it all worked out for you.
Like Greg said, the AW-32 should work fine even up there in cold country. Still, do let the tractor warm up properly before putting a load on it. It's just a good idea in general especially in the colder weather.
Let us know how it works tomorrow will ya?
Rob-

 

[studor]

Richard -- once you get below 0 fahrenheit the three point will take time to function even with AW32 - in my experience anyway
Because I leave the snowblower on most of the winter I have found that you can start the tractor to warm it up and then use the fel and power steering to warm the hydraulics or when the PTO is engaged it seems to generate enough heat to warm the hydraulics to a usable level in a few minutes - or you can buy a magnetic heater
regards
Steve

 

[RonMar]

If I ran regularly below 0F, I would use supplemental heat on cooling system, oil pan and hydro reservoir. That hydro pump has a long suction path to draw oil from the back of the tractor. Trying to pull cold oil from that distance can cause restrictions in flow which are hard on the pump.

Even the best designed and maintained machines break. Machines that are poorly cared-for break more frequently...

 

[Diamondpilot]

I knew the flush would give you good results. Its very important for others just reading that the oils that come in these tractors is junk. You must flush and refill with good stuff or you will chase problems right and left. Many flush the gearboxes also with kero or diesel.

Chris

 

[valley]

I fired up the machine this cold morning. Aannnd.... the FEL raised so as to make any man proud. Bucket full down and curl nice. If there is something to complain about I couldn't find it. The 3 poing is ready right now. All this with AW 32. After some things are done I still plan to go through the FEL Valve just because. I do have a flock of hoses to reend or replace, I hope to find the metric ends. The information, case histories and incouragement ,And close friend conversation took the pain out of this exercise. I thank
you! Richard Charshafian

 

[Diamondpilot]

Check with Ronnald at Ranch Hand Supply, he has a site, for the hoses. He can make what you want and sells kits of hoses. Granted he mainly deals in Jinma, but they may be the same ends. Just give him a call.

Chris

 

[valley]

Hi Chris, I got a quote to have one hose made in Nevada it was $43.08 each. I did as you suggested and checked on line, $65.00 each before shipping. I need 4 hoses, the choice is between $172.00 and $260.00 plus shipping. I'm still thinking maybe there is I can arrange hose and fittings from Discount hydraulics. Thanks for the help. Richard