Quick advice needed

   / Quick advice needed #1  

newbury

Super Star Member
Joined
Jan 8, 2009
Messages
14,118
Location
From Vt, in Va, retiring to MS
Tractor
Kubota's - B7610, M4700
My M4700 had a leaking FEL cylinder so I took it off. http://www.tractorbynet.com/forums/hydraulics/340994-advice-removing-fel-cylinder-please.html?highlight=#post4188377

I was advised to get plugs and caps for the hose ends but I have not got them yet. I capped them with plastic wrap and tape, then got a male-male JIC because I had to move the tractor. I removed the plastic wrap and tape and screwed the hoses to each other, strapped the FEL, raised it and moved the tractor about 40 yards.

Then later my BIL told me he had "blown" a hydraulic pump on a skid steer when he did similar. Is there any cause for worry? Would caps act much differently?

I explained to the guy at the hydraulics shop where I got the fitting what I was going to do and he thought it was ok, but I don't know the level of his knowledge.
 
   / Quick advice needed #2  
As long as you don't operate the valve, then no damage can be done since no fluid will flow to those lines. Damage would only occur if you capped the feed side of the valve and blocked the constant flow from the pump.
 
   / Quick advice needed #3  
It's no different than when you're trying to lift something that's too heavy. You pull the handle, full pressure goes to the cylinder, and nothing happens. The pump has a pressure relief... On top of that, you probably didn't move the lever to go "up", so that wouldn't have even happened.

I see no cause for concern.
 
   / Quick advice needed #4  
Your tractor has open center hydraulics, which means that, unless you move a lever, the only place fluid is moving is from the pump thru all devices and BACK to the tank. Your male/male adapter, if nothing else is wrong (other leaks, etc) was only keeping the open lines from leaking.

AFAIK, nearly ALL tractors plumb both lift cylinders in PARALLEL, which means that both sides get equal pressure - by coupling in and out together on ONE cylinder, the worst that could happen if you tried to raise the FEL would be the same as a catastrophic piston seal failure - the FEL would either stay put, or (much more likely) it would FALL.

By Strapping the FEL up, you avoided a "FEL FALL" -

Just noticed Kenny's more succinct answer - looks like you're covered... Steve
 
   / Quick advice needed #5  
By connecting the two cyl hoses together, you provided a path for the fluid to go if you moved the levers.

If you did not move the levers, the fluid would just flow through the valve to tank as normal.

Even if you capped the hose, and used the lever,the relief valve might protect the pump. .
 
   / Quick advice needed
  • Thread Starter
#6  
By connecting the two cyl hoses together, you provided a path for the fluid to go if you moved the levers.
That is what I was thinking and hoping.
If you did not move the levers, the fluid would just flow through the valve to tank as normal.
I moved the lever to raise the FEL, but did not "dump" or "curl", which was controlled by the removed cylinder.
Even if you capped the hose, and used the lever,the relief valve might protect the pump. .

MIGHT you say!! Might and protecting the pump are not words I like that close together in the same sentence! :)

My hat and my caps are off to you J_J and others.
 
Last edited:
   / Quick advice needed #7  
Might is a good word as the relief valve is there to protect the pump primarily.

Think about it, the relief orifice is a small orifice and designed to relieve the pressure and not design to carry the pump volume.

The weakest link in the circuit might break, be it the pump, hose, fitting, cyl, etc.
 

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