Hydraulic valve problem

[RyanL]

Hi, well i have a Bobcat model 911 backhoe attachment that i converted to 3-point. I just bought this backhoe and have used it about 3-hours, it had previously sit for 4 or 5 yrs. The problem is the dipper won't extend out, unless you do some other function at the same time and you have to have that other function at the end of its cycle. The dipper seems to crowd back all right. the dipper will also drift off when its fully extended and oil warm. The left stabalizer also acts the same way, both of these valves are on the same side.

 

[RonMar]

Sounds like a blockage in the main passage of the valve spool for the dipper extend port(won't draw fluid from the main gallery). It sounds like that function is able to draw fluid from the internal parallel gallery though(while another function is being used). I would pull that spool apart first and inspect for damage, then briefly apply some hydraulic fluid from the pump(messy) to see if any junk comes out of that spools holes.

How much was this thing used before you got it? The leakdown/drift could be caused by worn/corroded spools or bad seals in the cylinders. That is the problem sometimes with letting equipment set. If there was water in the hydraulic fluid, it will pool in spots and rust/pit surfaces that must remain smooth to function normally.

 

[RyanL]

Thanks for the reply RonMar, to my knowledge the hoe has seen very little if any use at all in the last few years. I am going to tear the valve apart i would say its in there, the dipper and left stabilizer have good power and speed when there is another valve in use.