Woods BH80X drifts after letting off the stick

[galaxie428]

Hi All. I have a BH80X on a Bobcat CT230, today while digging up a stump, I noticed that when I let go of the stick, the boom would keep drifting slowly to the right. It would do this whether I had the tractor running or not and it didn't matter if I had the hydraulics shut off to the hoe. Any ideas on what I should look for?

 

[LD1]

Not sure how the BX swing cylinders are plumbed.

Are they a pair of single acting cylinders like on a snow plow, that only have one hydraulic hose going to them?

Or are they a pair of DA cylinders that is a "push-pull" setup. Where pressure is directed to the base port of once cylinder AND the rod port of the other at the same time?

Its possible you got some air in the system and simply cycling side to side all the way a few times will solve the issue.

If its a pair of DA cylinders you could either have a valve leaking by, or cylinders seals.

If SA cylinders, you have a valve leaking by.

 

[Drunkwater]

I am chasing a similar issue on my backhoe attachment, which uses a pair of single-acting cylinders pulling on chains. I don't have gallons of oil spitting out the breathers on the cylinders, so internal leakage was eliminated at the cylinders (difficult to eliminate if the cyl is DA). On my machine there is a crossover relief, which I am hoping is the cause. I will pull it this fall after I'm done using the machine. The last spot would be the valve.

A good suggestion when I posted my question was to swap the hoses between the cylinders to see if the problem follows the valve, or stays with the cylinders. Good luck, it'll be interesting to hear what you come up with!

John

 

[galaxie428]

Thanks for the replies, I thought I would get an email when someone replied to the thread but I didn't so I assumed nobody responded and I hadn't checked back. I should have known better because folks on this site are awesome!

It has two cylinders, I will have to look at how they are plumbed because I am not sure without looking.

What made me check back to this thread was I had my hoe off and had a tiller on this past week. I have a hydraulic top link, the tractor has one set of rear remotes that the top link and the backhoe hooks in to. As I will tilling, I adjusted the top link to where I usually set it when I till which is about 2" from being fully retracted. I happen to look back when I raised it one time and when I lifted it, the top link went out about 6 more inches without me making it do it.

Saturday, I put my hoe back on to dig up a septic. I hooked the hoe into the rear remotes and went to lift the 3pt up to get them out of the way so I could attach the hoe into the frame. With the remotes engaged, the 3pt wouldn't lift. As soon as I in-engaged the remotes, the 3pt went up.

So now, I am thinking something is going on with the tractor but not sure what. Anyone have any thoughts on this?

I had a hose blow on the hoe a few weeks ago. It didn't loose much fluid before I got it shut down and after replacing the hose, I had to leave for while and when I got back I forgot to refill with fluid before I went back to the job. I didn't even think about it till the hoe started doing the drifting thing on the job but I finished up anyway. If I had to guess, I was probably less than two quarts low when I refilled after I got home.

Could this be happening because of air in the lines and if so, how to I purge it?

 

[LD1]

Without knowing more, I'd say he toplink extending on its own was air in the cylinder.

The 3PH not working with the remote engaged......Id call that normal in most cases, but dont know how the remotes are plumbed.

The 3PH is the last in line to get hydraulics.

Pump>3rd function if equipped>loader>remotes if equipped>3PH

That is the order of flow. Loader and remotes normally have a power beyond valve setup. Meaning when acivated, it ceases flow to everything downstream and utilizes its own return to tank line.

So with remotes active, hydraulic flow goes as follows.....

Pump>In loader P port and out PB>in remote valve (which is activated)>out work port A>to backhoe inlet port>out vackhoe return port>back in work port B at remote>return to tank at remote valve. Which has no flow going to 3PH

With remote not active
Pump>In loader P out PB port>in remote P port out PB port>3PH So full flow to 3PH

You will probably notice the same thing happen with the 3PH not working if you try raising the loader and 3PH at the same time,
You will probably also notice the toplink doesnt work also if trying to lift the loader at the same time.

Priority goes in the order I mentioned.