I have a Tak tb025. I recently blew a hose on one of the bucket rams. I fixed the hose and filled up with hydraulic fluid. Now the ram goes out fine but doesnt retract very fast at all. As the machine gets warmer the ram stops retracting altogether. Then after running for a while , the ram goes out fine when I push forward but when I pull back on control it continues to go out slowly instead of retracting. All the other rams work fine. Any help would be greatly appreciated. Thanks
How many bucket rams does it have? What hose was replaced.
There are four rams on the machine. One for bucket. One for thumb. One for stick and one for the boom.It's actually the boom ram . And it was this ram that the hose was replaced on. I thought maybe an air lock . Not sure if overfilling hydraulics would do that.
Could be that the piston seals are leaking badly (maybe the piston came off?), the cylinder will act as a one way cylinder pushing the rod out when you put hydraulic pressure on the retract side. That could have had something to do with blowing the hose if you forced the bucket with the stick when it popped the hose. I think I'd be checking the pressure by watching the hose for stiffening while you operate the controls. An air lock or overfilling the fluid won't do anything like this. I don't know anything about the hydraulics in that, there's a couple ways I can think of that the valve itself could cause this, but not sure what you have for function control valves.
The hose didnt actually blow. I knocked it of with a stump that rolled into the machine. I could see why it wouldn't retract if the seals were gone but why would it work fine when I'm extending the cylinder? And yesi was thinking maybe the ram itself detached inside the cylinder
I suppose it could be coincidental that it started doing this after I changed the hose. But it just seems weird
Did the stump hit the cylinder?
Yes I suppose it did. Didnt look to hit that hard though. As I say,it extends fine but retracts slowly until the machine warms up then it really struggles to retract
Hit it hard enough to scrub the hose off. Could have bent the rod, causing the piston to leak, or just jam. You might try removing the retract hose, capping the hose but leaving the cylinder end open. If you start with the cylinder extended, then there shouldn't be any leakage if you start it up and try the extend function. if it leaks, that's the piston leaking. While it's extended, you can put a straight edge (yardstick is close enough) on the rod to see how bad you bent it. It will still extend because there is more area on that side of the piston if the rod is binding, or the rod is the piston if the piston is gone (imagine a hydraulic bottle jack or old one way hydraulic cylinder and you'll see how a one way cylinder would extend with pressure on the retract side)
Thank you for that info. I will check it out tomorrow and let you know how that works.
Well I tryed a few things. When I retracted cylinder with hose plugged was still getting fluid through. Took ram off and had it rebuilt. Put it back on and it's still doing the same thing. It almost as if the one valve isnt closing so the pressure is fighting itself. It extends fine and all other controls are working fine. It's only the retract that doesnt qork correctly. Any other ideas guys?
Do your control handles connect to a valve bank with linkages? Do all the handles move the same amount? or is it possible this handle doesn't move as far once it's warmed up and stops functioning? Any oil seeping from the valve bank, or is it dry?
It actually will be good idea to check pressure on both ends of cylinder while retracting. One of possibilities is leaking load check valve.
My kubota has a counter balance valve on boom cylinder to keep it from dropping if hose breaks....if you were lift when stump hit....it would have tripped cbv if it is not use to tripping the valve might have stuck open...or not seat properly. My guess is yours has a cbv also.
Ok guys I'm back. Had the cylinder rebuilt . It's still functioning the same. We changed the hoses on the top of the control valve and found the symptom reversed itself. It goes down fine but diesnt want to come up it looks like there may be a small leak on the top of the valve not sure which one is leaking . Took bottom off the control valve but dont know how to dismantle the valve. Are they serviceable or do you just purchase a new control valve. Thanks for all the replies
On kubota you can just change the cartrage ...not sure on yours...if no one else can answer....i could tell you with an image
Would like to see what you change out
This is the kubota holding valve cartridges are removable. If you have pic of your valve it should be similar.
This is my valve assembly. Wondering if anyone knows how to get into deeper or do we just change the whole unit.
I dont think that is your problem...that is your joystick...could be but i think it is your holding valve
Hmmm. I don't know what a holding valve is.
Sorry i cant help you there...i dont know where it is on a tak
You could follow your hoses from boom back to main valve and see if you have one
Mine is right by cylinder..
Thanks for the help. Hopefully I will find more info on Monday. Was going to buy the service manual online but not sure if a safe sight
I buy them at trade bit....always works out for me there
We followed the hoses from the ram and they go straight into the main valve body. And the control lines go into each side of that as well. Nothing between cylinder and valve body