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BX-2380 air in hydraulic system

2880 Views 5 Replies 3 Participants Last post by  TUDOR
BX-2380 with LP 4-in-one bucket. Took delivery of new machine Sept. 2018. Back to dealer 3 times for same problem. Dealer has replaced the 4-line hyd quick disconnect (factory recall), and the center bucket hyd cyl. Symptoms: bucket does not hold position, it simply flops back and forth under very light load. Apparently, acts like there is air in the hyd cyl instead of fluid. Almost full rotation of bucket. In the video, I am NOT moving hyd control lever, just moving the machine F and R. You can see free play in all 5 of the hyd cyls if you look carefully. Hyd fluid level FULL when machine cold.

Before I return machine to dealer for the 4th time, what can I check? Thanks Steve


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The video shows free play in only the bucket curl cylinder. Watch the front tires as the tractor moves back and forth through all of the cycles. The lift and clam shell cylinders have no movement even though you are starting with the front tires off the ground.

As a guess, the piston seals in the curl cylinder is leaking badly. The proof requires a suitable pressure gauge, probably 3000 psi, and the dealer should have used one to diagnose the problem the first time.

The only way to inject air into the system, short of disconnecting and draining lines, is through the supply line from the reservoir to the hydro, or through a poorly sealed hydro filter. If air is being ingested, it can be heard as a static or crackling type of sound that doesn't go away as long as the engine is running. Air introduced by draining a line, or rebuilding a cylinder, is chased out of the system by the positive flow from the pump when the cylinders are actuated. It only takes a couple of full stroke cycles of the cylinders to chase the air out of even a pair of freshly rebuilt cylinders.

Tell the dealer to do a pressure check on the curl cylinder. It isn't acceptable in that condition on a new tractor and most likely needs a rebuild unless fault can be found with the curl valve spool.

As a check when you go to pick it up, hook a chain to the rod end pin of the curl cylinder and drape it over the bucket cutting edge. Use the chain to lift a 6' tiller, or something of similar weight, using the curl cylinder. And don't let him snow you that the loader won't lift that much. The lift cylinders may not be able to raise the arms any higher, but the curl cylinder doesn't operate at the same leverage disadvantage.
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Is it possible that the seals are failing in the cyl? Twice?
Yes, if they get nicked on re-assembly. Been there, done that.

A faulty new cylinder is much less likely, but even brand new parts have been known to be faulty out of the box. A pressure test would certainly help with diagnosing.

That leaves the valve spool or body as the likely culprit. Does the curl function work at all?

The bucket is heavier than a normal bucket and will affect the maximum payload capability for that reason. Otherwise, it should have no effect.

Lifting capacity of FEL seems to me to be well below specs. Light loads (full bucket of wood chips) will lift, but ever so very slowly.
Lifting speed is normally a function of engine speed. Heavy or light payloads should lift at very close to the same speed at a given engine speed. Lifting capacity is a function of available pressure. Excessive wear in the pump or a faulty relieve valve will affect both the lifting speed and pressure availability. Again with the pressure test suggestion.

As helpful as your dealer has been, I would think that he has done some pressure testing. I'm making note of the suggestion for your information should you wish to enquire.
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Brady, send him a PM and he will get an email notification, including at least part of your text. He hasn't been on MTF since his last post on this thread, 10 months ago.
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