3PH won't raise after interferemce with Draw bar

   / 3PH won't raise after interferemce with Draw bar #11  
Yep.. the schematic would be telltale. Another option is to check each port and look for flow that should be occuring, or is not occuring.

Soundguy
 
   / 3PH won't raise after interferemce with Draw bar #12  
If the hydraulic system was in distress for the entire 10 hours or there abouts, the system relief spring could very well have lost its spring. I don't know how your tractor is designed, but if there is a square looking cap under the seat with a allen or a large screw with a lock nut on it, that could be a complete system relief. If it is made that way, I would check it.
 
   / 3PH won't raise after interferemce with Draw bar
  • Thread Starter
#13  
Jerry,

With the cover off there two main blocks. The top one is a by pass of sorts that allows the lift system to be dirverted for external use. I confirmed this is the off position. The pressure relief is on this top block but has been replaced. The second block lies below the first block. There is a plunger and assume this is the main valve. The Draft and position cams push this in. With the fuild out I have confirmed the plunger goes in and out. The parts break down page shows several other check and safety valves in this block. I too bet there is a fatigued O-ring or spring. I'm sure it will be hard to look at these springs and determine it is bad. If I had the length and spring constant when new, it would be a start!
 
   / 3PH won't raise after interferemce with Draw bar #14  
That would be my bet.. that 2nd block may have a weak spring allowing oil to bypass.. the momentary diversion of flow lets the weak spring seat, and the lift operate... perhaps.. just guessing untill the block is open, or a schematic is seen..

Soundguy
 
   / 3PH won't raise after interferemce with Draw bar #15  
Paddy, I've read through this thread several times and I keep coming up with the same question that I have not seen answered. What happens with a partial lift using the position control? Let's say that you only move the lift control to the half-raised position. When you bump the FEL joystick, does the 3PH raise to exactly that 1/2 raised position and stop as it is supposed to do? Then, when the lift stops (hydraulic position control "nulls") the lift will not move up more until the FEL is bumped? If that's the case, what would happen if while the lift was actually still moving, you move the position control to another position (up or down)?

I guess I'm confused as to whether the problem occurs only at the lowest position or at any position of the 3PH when the circuit matches the lever position and stops moving. If it is the latter, can you lower the lift handle some and then, as the lift drops, stop the lowering by raising the position control handle? What if you then raise the position lever? It seems that only the FEL shock causes the circuit to operate. Normal lowering of the lift and stopping would also cause a slight spike in pressure, but that seems not to cause the raise to operate like it does when the shock is from the FEL.

Are you testing the 3PH with a load on it (boxblade?) or just the lift arms?

I know this is a lot of questions, but from your description, I started thinking that when the position control works, it works until the lift matches the position and then won't move up more until you bump the FEL. It will lower just fine, but to get it to raise more, you have to bump the FEL. When the 3PH does raise, it has all it's normal lift power, but only until it matches the lever's position. Then you have to bump the FEL to get the lift valve to go off of open-center and lift. Is that about correct?
 
   / 3PH won't raise after interferemce with Draw bar
  • Thread Starter
#16  
Jim,

Your last pargraph is correct. All the hydro parts hold well. I can leave the box blade up with several buckets of gravel as balist, for several days with out it droping.

I'm thinking it has to be a Return oil, check or safety valve. In the parts diagram there are 5 valves in this block.

Main Control valve, (must be working because it hold loads fine)
Safety valve
Oil return valve,
Check valve
Lower valve
 
   / 3PH won't raise after interferemce with Draw bar #17  
Does the unit have remotes?
Did he try to take the loader off?

BTI
 
   / 3PH won't raise after interferemce with Draw bar #18  
BTI said:
Does the unit have remotes?
Did he try to take the loader off?

BTI


see post #5 yes took the loader off..
 
   / 3PH won't raise after interferemce with Draw bar
  • Thread Starter
#19  
Follow up: I ordered the valve assembly from Chip at Artrac. I figure I could look at a pile of check valve springs and wonder, is this OK? Seams "springy"

All, Thanks for your help in locating....maybe I should wait until it works!
 
   / 3PH won't raise after interferemce with Draw bar #20  
Keep us informed of the progress on this issue... especially if you disassemble the old valve ( assuming the new valve fixes the issue. )

Soundguy
 

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