Hello All, Im new to this is forum. The reason for me joining is a problem that arose while working on my fathers excavator. The right track is stuck in reverse position. From the lever inside the cab that controls the track there is a linkage that connects to a cable. The cable is routed to another linkage that drives a shaft up or down inside a " valve body" (Picture below). This shaft is binding and thus the right track is stuck in reverse. I have pulled the shaft out of the body from the top and see some metal particles and signs of grinding. Question is what could be causing this and what should i do to correct it?
Welcome to HEF exkavatorz. :drinkup That shaft is typically know as a valve spool, not unusual to see that kind of scuffing on a spool of a machine with some age. As long as the control lever, the linkage, or the control cable is free working, or that centering spring shown in pic is not broken, no reason why it should be stuck in reverse by that spool. However, if it were stuck in reverse, and you couldn't get the control lever to come back to center, you likely had a metal fragment preventing the spool from centering, I've seen it happen before. There's no telling where that fragment came from. Hopefully the fragment will leave the spool and head for the hyd filter where it belongs, and hopefully that fragment didn't come from some kind of major component damage in the system.
Thanks willie59!! When I pulled the valve spool out i lost about a gallon of fluid through the opening. Would "flushing" the opening with fluid help wash out and fragments....? Im thinking if i pour more fluid in the tank it will come back out of the opening and flush the fragments. Ill add that it was pretty tight coming out. It would spin 360 degrees but stubborn to come out the top.
Hard to say if it flushed out. I've had success running a mechanics magnet down the bore of the valve body, other times the fragment remained elusive. All you can do is put it back together and see if it worked out.
I've seen a chunk of rubber from the inside of a hose do it, too.
So here is an update of what I have found in the valve body after I took out the valve spool. I used a mechanics magnet as suggested. The round pin was located towards the bottom of the spool. See pictures. Im thinking this cant be good :beatsme Any idea where this could have originated from?
Can't say about the stuff that looks like fine wire. But that pin, can't be certain, but that looks like a pin out of a hydrostat pump or motor. Since it was lodged in the control valve section for right drive, I'd warm up the hyd system, take the case drain line loose at right drive motor, and connect a short piece of hose to the case drain fitting on the motor, drop the end of the hose in a clean bucket. You're going to need a proper plug for the hose you disconnected from case drain fitting to prevent oil loss. Raise the right track off the ground with the hoe and operate right drive in both directions, hi and lo speed. Two things, check to see how much oil comes into the bucket in a minute, and note any debris that comes out of the case drain.