3 PTH not working

[tallt]

I have a Jinma 284 with FEL and BH. I've taken the BH off and tried to use the 3PTH. Nothing! I've turned the draught control and received no results. Removed the draught control and cleaned it, but still no results. I've turned the steering all the way to the right and tried the 3PTH. Still nothing. >:(The FEL works well and so did the BH. Anybody have any suggestions as to what I should try next to get the 3PTH to work?

[Ronmar]

"draught control"? I don't know what that is... First off, is there a knob located down in front of the seat. It looks a little like a garden hose valve handle, only it is probably made of black plastic. Make sure that it is unscrewed(counter clockwise).

This is the speed regulating valve that slows the flow out of the 3PH so a heavy impliment dosn't slam to the ground when you try and lower it. If this valve is turned fully clockwise, it could be preventing the fluid from getting to the 3PH cylinder...

Ron

[3RRL]

tallt said:

I have a Jinma 284 with FEL and BH. I've taken the BH off and tried to use the 3PTH. Nothing! I've turned the draught control and received no results. Removed the draught control and cleaned it, but still no results. I've turned the steering all the way to the right and tried the 3PTH. Still nothing. >:(The FEL works well and so did the BH. Anybody have any suggestions as to what I should try next to get the 3PTH to work?

tallt,
What year is your 284?
Is your BH a 3pt mount? How did you get it off then, by using your BH controls I presume? Also, is your BH driven off a pump on the rear of the tractor or one on the PTO?
I've been told if the knob under your seat that Ron talks about, that if it's turned closed (all the way in) it will disable your 3pt and activate the 1/2 remote valve. So you have to unscrew it like Ron said, for your 3pt to work.
If that doesn't work, you might check the lift box to be sure your 3pt cylinder is working properly. On my Kama, I had it get stuck all the way out once and the 3pt would not raise.
Let us know what you find.
Rob-

[tallt]

I've gone through the motions of fiddeling with the control knob under the seat, but to no avail. The JM284 is a 2006 model. The BH is mounted to the 3 PTH but that's all. It gets its hydraulic feed from 2 hoses, one which comes from a small cast block beside the steering box and the other comes from the main hydraulic lever valve of the FEL. When I disconnect the BH then I have to join these 2 hoses together or I can't start the tractor because of pressure build up in the system. Where is the lift box? My manual which came with the tractor is less than something to be desired.

[tjcarothers]

TallT,
I also have a 2006 Jinma 284, and a 3-pt hoe that is a direct connect like yours. Sounds like you are doing everything right. I am assuming that your steering and FEL work OK after disconnecting the hoe? I read once somewhere that sometimes the ports on the hydraulic diverter valve (you called it draught control) are plugged, making the 3pt not work. I don't know if you can just unscrew the valve and clean it or not. Hopefully someone else will remember. I will do some research and get with you on it.

TJ.

[3RRL]

tj,
I like your new avatar! ;D

tallt,
I think your hydraulic box is right under your seat. Sounds like tj is giving you a better option to check out first though.
Rob-

[Ronmar]

I got your PM, but decided to answer here.

Being able to lift the arms by hand is normal as the upper arm linkage inside the lift box is not connected to the piston, it just rests against the piston, so you can lift it up any time. this also means that the 3PH can provide no downforce.

OK, I read your description of how your backhoe is plummed. It sounds as if it is taking the output from the FEL sending it to the BH and back to the diverter valve(small cast body up in front of your right foot/gas pedal when seated) From there the flow should be either to the steering while turning the wheel, or back to the 3PH control valve located on the right side of the lift box.

If the 3PH is not going up with the speed reg knob spun fully counter clockwise, then the fluid must not be getting sent to the cylinder from the control valve. Or it is not reaching the valve from the diverter valve. I think this last one unlikley, as I understand the workings of the parts in the diverter and steering. The fluid must ALWAYS flow, and fluid only can flow thru the rotary vane pump at the bottom of the steering column when you are actually turning the steering wheel. When the steering is turned, the diverter diverts the flow from the 3PH and sends it to the steering valve.vane pump. If the diverter was hung up unless you are turning the steering wheel 100% of the time, the fluid would be obstructed by the steering valve/pump.

I think what is more likley is that you have an issue with the 3PH control valve back on the right side of the lift box under the seat. The lift box is where the upper 3PH arms are attached to. It is also the hydraulic reservoir. 100% of the hydraulic flow passes thru this valve and into the lift box/reservoir unless you are turning the steering wheel, then the fluid diverted to assist the steering leaves the steering valve/vane pump and returns to the reservoir via the line on the left side of the gearbox.

The main flow from the diverter down the right side of the gearbox flows unrestricted into the reservoir when the 3PH lever is in the lower or neutral/hold position. When in the raise position, the flow into the reservoir is diverted to the 3PH cylinder via a safety relief valve on the upper front of the valve and that speed reg valve at the front of the cylinder. Restriction in the cylinder is encountered, pressure builds and the cylinder goes up.



One of two things could be happening IMO.
1. The internal linkage that connects the control lever to the spool valve is somehow disconnected and the spool is never leaving neutral and no fluid is being sent to the 3PH cylinder. Does your 3PH control valve look like this?
johnstractor.homestead.com/files/HydValve.jpg
If somehow part #29 got disconnected or is not moving the spool(#14) then the valve will never divert the flow to the 3PH cylinder.

2. Something is wrong with the safety relief valve(part #1-#7) and that valve is stuck open allowing fluid to pass freely to the reservoir thru the safety passage instead of building pressure and lifting the 3PH.

I find a mechanics stethescope(3-7$ at harbor freight) can be handy for troubleshooting these things as you can hear the fluid flowing in the lines when the valves are actuated and get an idea where to do further disassembly and inspection. With the tractor running, you should hear fluid flowing thru the line from the diverter valve back to the 3PH valve. When you command a lift, you should be able to hear fluid flowing past that safety valve and also at the speed reg valve if fluid was flowing into the 3PH cylinder.

Ron

[tallt]

Thanks for the info Ron. The schematic that you show for the 3 PTH valve is the same as mine. I will check the fluid running with a stethescope first and then check the internal workings. I'd rather check the small things first before I start lifting and pulling apart lift boxes.

[studor]

Just a thought -- how cold is it and how long did you have it warming before trying the hitch? -- you might want to try changing the suction filter before tearing anything apart. When below freezing on my 2006 284 (and on lots of others from what I read) the 3 point needs AW32 and a wide open (bigger than at least 30 micron) filter to move -- yet no problem with FEL or steering. In hindsight I think my filter was a big part of my problem with the 3 point in late fall.

[Ronmar]

studor said:

Just a thought -- how cold is it and how long did you have it warming before trying the hitch? -- you might want to try changing the suction filter before tearing anything apart. When below freezing on my 2006 284 (and on lots of others from what I read) the 3 point needs AW32 and a wide open (bigger than at least 30 micron) filter to move -- yet no problem with FEL or steering. In hindsight I think my filter was a big part of my problem with the 3 point in late fall.

The same fluid that flows past the loader and steering feeds the 3PH, if it was a suction or flow issue, you would have problems with the loader and power assist on the steering. The steering works pretty well without the engine running, so it uses very little of the available flow from the hydraulics anyway and would be the least effected by poor flow. That 3PH control valve is a single spool valve very similar to the loader control valves. A reduction in flow from cold fluid/restrictive strainer would seem more evident on the large diameter 3PH cylinder because it takes longer to fill, but it would effect the other systems also... If loader, steering and BH are working with the available flow, then the problem lies with the 3PH or control valve.

30 micron is way too small on the suction side of any hydraulic system and cold weather/thick oil would only make this worse. A typical hydraulic suction strainer is made of a single layer of #100 mesh screen. This is roughly equivalent to 149 micron...

Some schools of thought say do away with the suction strainer altogether, as it can cause added pump wear due to cavitation in the pump from restricted flow. The focus instead should be on a good low micron(10 or less) return line filter and keeping the reservoir clean and it's air vent filtered.

Ron

[studor]

Okay -- so you don't like my thought ;D
RONMAR -- I agree with everthing you said and went through pretty much the same logic in the fall -- figuring that if the FELand steering worked (which they did) that the three point should as well -- and it would after about an hour warm up -- which I found out by leaving the tractor running one day while I shovelled out some equipment -- finally after reading many threads from learned folks such as yourself I had visions of tearing apart my tractor in freezing temps and three feet of snow.When I swapped the second chinese filter for a NAPA filter and changed oil again -- MAGIC. Then noting from further threads how bad a 3o micron filter could be I found a Donaldson with 150 micron rating and installed it -- no noticable improvement but -- hey at the price of those strainers it must be better ;D
Sorry just one of those errant thoughts -- must be spring fever

[Ronmar]

What spring?
I was dodging snow flurries welding on my tractor this afternoon...

Ron

[studor]

Sorry to rub it in -- it will be over 70 here today -- with a three foot bank across the street -- welding keeps you warm?

[studor]

Have you been able to get the hitch working?

[tallt]

I sort of got the 3PTH working, but not because I did anything that caused it to do so. After checking the draught control and cleaning it, adding oil, because it was a tad low, and a few other things that other members suggested I still had no working 3 PTH. At this time I didn't want to take apart pistons and replace stuff because I had need of the BH again. This is when the unexpected happened. After backing the tractor to the BH I hooked the 2 top links in their respective positions. Then I placed one of the lower arms in its respective position, but the other one I couldn't because the BH was not level. I had the hydraulic lines already hooked up and without thinking I moved the lever to raise the 3 PTH. Lo and behold the one arm moved and struggled to raise the BH and did so (straining) until the other arm came in line to place the pin. I have no idea why it did this. All that I did that was different was hooking up the BH hydraulics to the tractor. This is where you disconnect the lines from the couplers and hook up the BH lines. Anybody have any ideas what happened?