rock shaft issues

[GreatWhitehunter]

I recently had a power beyond kit installed for my 448 hoe. I took the hoe off for the first time today to use my rake. I noticed the rake kept lowering and the machine making a strange noise. I checked all the connection and everything was tight. I was due for a hydo fluid change so I figured I try that since I was a little low. I replaced the fluid and the large filter. And cleaned the inline filter. Put the tractor back in operation an the problems still there. Before the PB kit was installed I never had an issue with the rockshaft, so I'm thinking there related. Does anyone have any ideas as to what it might be?

Matt T.

 

[jdbower]

Are you looping the two PB ports together when you take off the backhoe? If that's not the issue there may be some debris in the system from the installation that needs to be cleaned out.

 

[Cidertom]

Sorry, it sounds like the work left some crud in the line. You are describing something stuck in the rockshaft valve. Usually slow drop, followed by sudden lift. The noise is the rock shaft metering flow to try to keep position. Sometimes it can be cleared by full cycling from low to high fast several times, but most times you have to clean the valve. It was the one headache my old 4300 had. They must have had to open up the lines between the inline filter and the valve to install your power behind. My 4520 came with the BPY installed, so I don't know what it looked like before.

 

[GreatWhitehunter]

Yes, I'm looping the PB ports. I noticed there seems to be another inline filter on the PB frame work. Perhaps theres something in there restricting flow. The rockshaft droops alittle and then rises up again. It's super annoying. It seems to me that is there was a leak in the circuit I'd see it right?

Matt T.

 

[kennyd]

I would get it back to whoever did the PB install. Sounds like they did a crappy job

 

[Cidertom]

Yes, I'm looping the PB ports. I noticed there seems to be another inline filter on the PB frame work. Perhaps theres something in there restricting flow. The rockshaft droops alittle and then rises up again. It's super annoying. It seems to me that is there was a leak in the circuit I'd see it right?

Matt T.

The leak is inside the valve. Instead of a plumbed "tank" port, the rockshaft valve just dumps directly into the sump. So unless you open up the tractor you won't see this particular leak. There is an adjustment to set how much the arms drop before recovering. The tighter the adjustment the more it cycles (with more noise) the looser the larger the drop before it recovers (less noise). Also if you try to cycle flush the valve, have the drop adjustment all the way open.

I don't know the how/why JD made the rockshaft valve so susceptible to minute debris. It seems that all the JD CUT line of tractors have had this problem. The inline filters helped the problem, but I still worry. I am extra careful to keep the caps on the BH and clean connectors each time I couple.

 

[GreatWhitehunter]

So it sounds like I need to contact the dealer. The suggestion you folks have given might clear the issue but it's unlikely.

Matt T.