Sudden Slow 3 PT

Smalljobs · Sep 23, 2009

I'm approaching 100 hours now on my Jinma 284 and suddenly the TPH has slowed down. For the first 60-70 hrs I was using a Jinma chipper having a posted weight of around 800 lb. I was always raising and lowering the chipper when I moved the tractor around and I could always raise it at idle.

Now I have a Rubbermaid barrel counterweight with 7 bags of Sakrete weighing 80 lb each and some misc hardware totalling around 575# plus the 7 gal of water used @ 8.3 lb/gal = 630 lb. The cross shaft goes through the middle of the barrel. When I finished the barrel 2 weeks ago I'm pretty sure I could raise it on "idle". Now it won't budge until I raise rpm to around 1200.

In the last 2 wks, I've been doing a lot of loader work on an up and down incline and find the power steering to be occasionally sluggish in each direction. The first time it happened I raised the wheels with the Koyker bucket, cycled them back and forth and it all cleared up.

I have not changed the 3 PH adjustment for lift range or stroke.

I wonder if the sluggish steering and now slow TPH are related and what is going on? I'm concerned it may worsen and I'd like to get this resolved before winter. On top of this, I have all the fluids for the big fluid change but don't want to change anything until I understand the TPH problem.

Loader and steering work fine but TPH problem persists.

Any ideas would be greatly appreciated.

greg_g · Sep 23, 2009

Sounds like the counter-weight sits farther away from the tractor than did the chipper. Lift capacity is based upon the center of gravity of the load being ~24" behind the lift point. All else being equal, if the center of gravity of the counter-weight is farther back than the center of gravity of the chipper - it's going to represent more "weight" to the hydraulics.

//greg//

Smalljobs · Sep 23, 2009

Thanks Greg,
The CG of the counterweight is 25" back from the C/L of the toplink pin closest to tractor. It's 32" from the C/L of the TPH upper arms that do all the lifting. That's the point where the arms exit from the housing.

The heavier (borrowed) Jinma chipper is no longer here and I don't recall the location of the pins and especially the flywheel.

Diamondpilot · Sep 23, 2009

Steve, I have seen your counter weight and its not a CG problem. Think of what a Bush Hog weighs and how far back the CG is on these things. I put my money on one of 3 things. Since your tractor is a newer model I would first change the suction side spin on filter. Next thing would be take apart the priority valve and clean it up. Last and hopefully its not the case is a pump that is going south.

Chris

erj · Sep 23, 2009

Steve,
Did Bolton Power change out the original fluids before you got it?
RonJ

Smalljobs · Sep 23, 2009

Bolton Power did all the right things, changed fluids, adjusted clutch, etc. Now it's time for my own fluid change.

erj · Sep 23, 2009

Steve,
Do you have a pressure gauge to tell what pressure you have in the hydraulic system?
RonJ

Smalljobs · Sep 23, 2009

Ron..tks,
Pressure gage is on my workbench and just arrived. More to follow.

greg_g · Sep 24, 2009

Smalljobs said:
Thanks Greg,
The CG of the counterweight is 25" back from the C/L of the toplink pin closest to tractor. It's 32" from the C/L of the TPH upper arms that do all the lifting. That's the point where the arms exit from the housing.

Actually that 24" is measured from where the vertical link pins to the lower lift arm. Too bad you don't have the chipper anymore to see if it still raises faster. If it didn't, you can reasonably conclude that the problem is hydraulic. But without something else to compare to lifting the counterweight, we're still at the guessing stage.

//greg//