3-Point Hitch Jinma 284 - 3PH needs warm up before operating

[KurtK]

Tractor: Jinma 284 (2005) with FEL & 3-point hitch.

I have a brush hog on the 3PH.

Typically, I need to have the tractor running a good 20-30 minutes before the 3-point hitch can be lifted. The FEL will operate beautifully as soon as the engine is running smooth, but the 3-point won't budge until 20-30min of running.

The fluid is fresh, the hydraulic filter has a bypass valve (selected after much research on this forum). It's relatively warm outside now. Once the 3-point becomes operational, it works just fine.

What do you think?

Thanks!
Kurt
Cashmere, WA

 

[greg_g]

Well the 284 is a single pump, single loop system with a PV for the steering sub-circuit. Presumably your FEL is factory, and is plumbed in immediately after the pump. This configuration makes the 200 series hydraulics - as a system - more prone to flow issues than multiple pump/independent circuit systems. Based upon what you've posted so far, I'll speculate this "bypass valve" that you plumbed into the loop may be diverting fluid from - or restricting flow to - the rear lift cylinder.

Don't know about yours, but some 200 Series had a fair sized hex head bolt sticking out of the left side of the hydraulic sump. If memory serves it might have taken a 19mm socket or wrench. It's actually the head of a valve that's located inside the sump, the purpose of which was to divert flow from the lift cylinder to a single rear remote. Popular opinion is that this single remote was to operate something like a dump trailer where hydraulic pressure was needed to lift, but gravity was relied upon to return flow to the sump. So on those tractors so equipped, not having that valve fully closed definitely affected lift cylinder operation

//greg//

 

[RonMar]

When it does lift, does it stay up? How/where is the speed reg valve(down in front of seat) set at? Unscrew it a turn and see if that has any effect on cold performance.

Do you have any way to measure system pressure? There is a pressure relief valve on the 3PH control valve. It is under a square headed plug on the top of the valve block. It's opening point is set with flat washers stacked against a spring. A pressure gauge in the system will tell you what pressure is being built up when trying to lift the Brushhog. Do you have the single quick connect pressure port that points out behind the seat and is connected to the bottom of the 3PH valve? If so, it is real easy to put a pressure gauge on a male QC fitting and plug it into that port. A 3000 PSI gauge plugged in there will read the system pressure being applied to the 3PH cylinder when you try and lift tge 3PH...

 

[KurtK]

Ron -

When it does lift, the brushhog stays up unless I purposely lower it. I did play with the speed adjustment a little (one turn max either direction) without any change in cold operation.

I don't have a hydraulic pressure gauge handy but I'll see what I can dig up. When cold, I don't get the sense that pressure is building up; I don't hear the engine bog down at all as if the pump is working harder when i try to engage the lift.

thanks

 

[geobar]

I have the exact same model and year with similar symptoms -- at idle when cold, the factory fel is fine and no pto lift. But if I raise the engine speed to 1500 the pto will lift when cold and be totally normal when the system warms up in about 5 minutes. Does yours lift when cold if you raise the rpm? I do not know what the solution is, But I too tried adjusting the knob in front of the seat with no luck.

 

[Affordable]

What weight of hydraulic oil are you guys running. ? Flush the system with about 2-gallons of diesel,put in new AW032 weight oil,if it speeds up once the hydraulic fluid gets hot and thins out,the weight of the oil is most likely your problem. Universal hydraulic fluid is 046 weight much thicker

Tommy
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