Link Belt HTC 8640 Pump

[Nicholift]

My son has a 2000 Link Belt HTC 8640. The hydraulic pump blew out the unloading valve, is making noise and performance is significantly diminished. LB has gave us the part #F7J0015SPL, and the cost $19,000.00, but do not have one available. The data plate on the pump is no longer on the pump, so trying to find one that way is out, but why I'm posting.
Anyone have this model and have the dataplate information?
It may be a Gresen (Parker).

 

[crane operator]

Any competent hydraulic repair shop, should be able to repair yours, or find a replacement one. Take it in and throw it on the counter. The replacement may not be a Parker one, it may be a aftermarket pump builder.

 

[CraneMechanic73]

Is your pump driven off auxiliary drive from back of engine?? Sits right on top of transmission??

 

[Nicholift]

Mounted to the inside, from what he sent me.

 

[crane operator]

That’s just a valve stack, not the main pump in your picture

 

[Nicholift]

Sorry, thats where it blew off the unloading valve. He dropped it off to Link Belt this morning.
I'd guess they are PTO driven?

 

[crane operator]

Blowing off a “unloader”? I’m not sure if you are talking about a relief port, but most reliefs don’t dump oil externally. They typically just release oil into a return to tank line.

Popping a relief isn’t typically a sign of weak pump, weak pumps won’t put out enough pressure to pop a relief.

I think I would be doing some pressure checking and diagnosing before condemning the pump.

But I really don’t feel like I have enough info to advise. I do own 2 8640 HL and if you need pump numbers, I will see if there are numbers on mine

 

[crane operator]

As far as pump drives goes, my two 8640's are both allison transmissions, and the pumps sit right on top of the transmission like what CraneMechanic73 talks about. I don't know how the manual transmission 8640's are run.

 

[Nicholift]

Item 6 in the diagram, unloading valve. Blew the internals out of it.
Relief valve makes sense, but thought of it operating like an unloading valve on compressors.

 

[crane operator]

Typically that "unloading" valve in the diagram is just a spring stack- it acts like a buffer. If you are booming down fast and suddenly stop, that spring stack takes up a little bit of the hydraulic shock.

Are we a new operator and not real smooth on the controls yet?

 

[Nicholift]

He's been at it for a few years. Heavy equipment school in Dothan AL after the Army. Crane school in WI.
Worked on Amazon or Google crap in WY with a traveling crew. Back to N. IL for a couple years, then a company in WI for a couple more. He had the opportunity to go to FL and took it. After a year he bought one and has now been on his own for a few months.

Speculation, from a crane mechanic at the former employer in WI, is that the noise is a stuck valve (debris) causing a high pressure situation in the system.
I repair commercial trucks in N. IL and have never touched a crane. Very hard to diagnose over the phone to FL with no practical knowledge of the vehicle or systems.
I appreciate the information you are providing. It will help me guide him through it.

 

[crane operator]

It looks like the stack you posted pictures of, is actually the winch stack, if its a single winch machine. The more info you post, the easier it will be to "remote" diagnose.

I hope for him its not a bunch of debris in the system because that's a huge pain.