Clark 664c dumping hydraulic fluid

[lshobie]

hey guys every time I drop the blade hydr  fluid gushes out the top of the reservoir.  there must be some kind of bypass....any ideas what is wrong and where to look?

thanks

louie

[OntarioAl]

If your tank is not overfilled it is probably the tank vent not allowing air to escape fast enough as the oil surges back into the tank.
I am not familiar with the Clark system and they may very well have a regenerative circuit that's putting oil from the rod end to the tank rather than direct it at the base end of the cylinder
my thoughts
Al

[The Wanderer]

 My 664B started doing the same thing last summer .I changed the hyd filter in the tank but still the same .The air is already in the oil going into the tank when lowering the blade .Try revving up the engine and cycle the blade up and down a few times .If it seems to cure its self temporarily then probably the seal on the pump shaft is sucking air and needs replacing . I have my clark stored for the winter but I will be working on resealing the pump in the spring . Hope this helps let me know .

[lshobie]

Thanks please let me know what you find - still having this issue - seems to be worse.

[lshobie]

So I have a leak in a steering ram and I pulled it - the shaft is pitted and I'm having it rebuilt..  There was water in the fluid - I've been running atf in the system.  I also pulled the hydraulic steer/blade pump and to open it up and replace the seals would have cost me as much as a new surplus pump so I just ordered a new pump.

Going to replace the suction hose as the old one was just a rad hose apparently and I'm going to disassemble the tank and clean it out as well as the suction strainer.

While the skidder is down I'll rebuild the steering lever bushings - she's pretty sloppy.

[The Wanderer]

Did you ever figure out what caused the hydraulic oil to push out the tank ?

[mike_belben]

Overfilled or mud nest in the vent line are my initial thoughts.  Does it utilize a pilot operated dump valve to bypass the cylinder spool and vent direct to tank?  If so that may be and add-on  routed to tank up too high or on the wrong side of a splash baffle.