Hydraulics Mystery...

[noobfarmer]

The hydraulics on my tractor are behaving very strangely. And I'm hoping someone on this forum with more experience than I can suggest a cause and fix.

My tractor has a FEL, as well as two remotes and a 3-point hitch. Everything worked fine until yesterday when I added two 6-foot hoses onto one of the remotes to extend it from the side to the rear of the tractor. Got everything hooked up and tested it out. The two remotes and the FEL work just fine. However, my 3-point lift no longer works.

What's strange is this. If I move the position control to up, the 3-point moves a up little but stops short of actually raising my implement, like it's straining but doesn't have sufficient force. But if I pull on either of of the remote levers (while unattached to anything), the 3-point hitch immediately responds and moves up. However, if the remotes are attached to something and I pull on them, the 3-point hitch doesn't move.

I wonder if I introduced some air into the system or something. The strange thing to me is that the remotes would affect the 3-point hydraulic pressure. This is a closed system. Belarus 9345 tractor.

Any suggestions? Thanks!

- Doug

 

[Leejohn]

It sound like to me that the remotes do not have the PB fitting in the valve. Just a guess.

 

[J_J]

I don't believe closed center systems use PB fittings as all the valves are in parallel.

All valves are pressurized by a common line.

 

[STx]

I doubt this is it but, have you checked your fluid level? Adding 12' of hydraulic lines will lower the level some, unless they had fluid in them when you installed them.

My guess would be possibly a divertor valve issue. Either in the wrong position or maybe an o-ring failure. I'm just guessing though.

 

[noobfarmer]

I was mistaken. The system is open, not closed. Does this make a difference in what may be the problem?

 

[stuckmotor]

I doubt this is it but, have you checked your fluid level? Adding 12' of hydraulic lines will lower the level some, unless they had fluid in them when you installed them.

Times 2

 

[noobfarmer]

Times 2

Yes--I did top off the hydraulic fluid, which was low. Another interesting observation: with no load, the 3-point will raise and lower fine. Just doesn't work with an implement attached. I was thinking there must be some air in the system that is reducing the pressure/thrust on the 3-point. However, what doesn't make sense to me is that if I "dead head" either of the remote valves (with the position control in up position) the 3-point pops right up with a heavy load attached.

 

[Leejohn]

With no load and remotes in center you could have about 300 to 600 psi and that well raise the 3pt. Now when you deadhead the remote it's putting high psi to the 3pt and well work good. Show a picture of the remote valve. I still say the PB fitting is missing or it's plumbed wrong. Your tractor is open center system.

 

[noobfarmer]

Thanks for the input. I've mapped out my hydraulics:



And the PB appears to be plumbed correctly:



But now (after a few days of dinking around) I still get good pressure in the FEL, but neither the 3-point of either of the remotes have strong pressure. Before I could deadhead a remote and get the 3-point to lift, no longer the case. What's the next step? Should I get a pressure gauge and see what kind of pressure I'm getting in the system? I checked the oil filter and it looks OK. The factory spec is 2700 psi.

Also, here is a picture of the top of my 2nd valve (i.e. attached to PB port on FEL valve). What is the tall, dome-shaped thing (label A). It appears to have a rubber cap at the very top.



Is this a pressure relief valve of some kind?

Thanks!
- Doug

 

[Leejohn]

yes you should have a psi gauge. The first thing I would do is to pull out that fitting for PB port and make sure it's a PB fitting and not just a reducer. The tank line should be the same size as or bigger then the in line, but that has nothing to do with the trouble you are having. That well only slow down the FEL and make heat.
You said you were dinking around, just what dinking around did you do? The A cover, I think you are right other wise I don't know for sure.

 

[noobfarmer]

Thanks for the suggestions! 3 more quick questions:

1. What if the fitting is not PB (i.e. just reducer)? Is this a big problem?
2. Is it worth swapping out the OUT hose with a larger size to match the IN? Would this materially improve the FEL performance?
3. I want to check the fluid for aeration. But to see into the reservoir I must remove the filter. Is it OK to run my hydraulics for a few minutes with the filter removed?

I'll post back after I figure out the correct fix. I bought a PSI gauge today and I'll test pressures tomorrow. Thanks!

 

[Leejohn]

#1 you would not have high psi after that valve. #2 Wait on that, but yes it should speed it up and help hold down heat. #3 I would not do that if you are talking hyd filter.

 

[the old grind]

"What Leejohn said." ^^ btw, 3 line/fitting sizes, or optical illusion? Tractor has 12 GPM pump flow, yes?.

I'll risk any backlash by suggesting 1/2" min lines/fittings for 12 GPM and 3/8" only for 6 GPM valves/use.
Also, I beg you to replace malleable iron street 90s (what they look like, .. 300 PSI or less max) or they will fail in time at >2k PSI.

Be sure "PB" and "return to tank" (pic #2) aren't reversed. (?) May help to plumb up some 'adapters' beforehand to ease gauge connection at various points in the system, including QDs to test FEL lines etc.

 

[bigchevy]

i have a massey ferguson 451 with shuttle shift and for some reason the hydraulic system seems to stop working i clean the filter an its full of sludge an replace it and happens again any way to flush the system i cant get more then 15 to 20 minutes out of the new filter ?

 

[bigrob70]

I have a farmtrac 360 the loader and 3 point hitch and remote values stop working. Was wondering if it could be the filter or did the pump just stop working?