Hitach pump failed

[ktl dig]

Hitach zx330/5 both pumps failed the sign the damages cool by citation anybody got any ideas that causes done 4800 hr

 

[Diesel Dave]

Can you confirm the model ? I don’t know of a ZX330-5.
Machine has always shown signs of positive pressure in the hydraulic tank ?
Suction screen in the bottom of the hydraulic tank in good condition not plugged / not torn ?
Any sign of water in the oil ?, Any recent “bad“ oil sample results ?
Do you have any pics of the internals of the two pumps showing the damage ?

 

[Welder Dave]

I can understand both pumps failed. The rest of your post makes no sense at all. Pumps shouldn't fail at 4800 hours unless something drastic happened.

 

[Tones]

I can understand both pumps failed. The rest of your post makes no sense at all. Pumps shouldn't fail at 4800 hours unless something drastic happened.

Debri from a failing pump can pass onto the other pumps.
Rereading the OP and trying to interpret it suggests a cavitation problem. Pumps hate cavitation so there's the problem. What's causing it can be a few things like sucking air or lack of pressure in the hydraulic tank and low oil level.

 

[Welder Dave]

Very unusual on a Hitachi with only 4800 hours.

 

[Acoals]

Very unusual on a Hitachi with only 4800 hours.

With appropriate levels of abuse and neglect anything is possible . . .

 

[IceHole]

With appropriate levels of abuse and neglect anything is possible . . .

Amen. I've seen low hour excavators at Ritchie Bros that you'd have to run like it was a drag like from all the slop. House stops turning and the bucket stops 2 seconds later

 

[Welder Dave]

A 330 is a big expensive machine that typically wouldn't get as abused as much as smaller machines, unless of course it was one of the machines owned by the company Vetech works at.

 

[ktl dig]

Hitach zx330/5 both pumps failed the sign the damages cool by citation anybody got any ideas that causes done 4800 hr

Both pumps failed and they’re telling me it’s are cavitation problem Trying to figure out what’s going wrong it’s never been low in oil in New Zealand we have to have anti-drop valves and I was wondering if they could cause it it’s also a long reach and it’s my baby so it’s not abused The anti drop valves are so the place on the rams so that if we lose a hydraulic line it can’t drop onto the guys well we were asked could we get the cavitation

 

[Tones]

Prior to the pumps failing did you notice if the oil was foaming? Were the pumps opened up to ascertain why they failed or did someone just say that was the cause?
Old hydraulic gurus have always told me that cavitation is pumps sucking air and the only place that can occur is between the tank and pumps. The oil in the pressure side of the system returns to tank and not directly to the pumps.
Fitting new pumps requires what,where and why the originals failed and not doing so is double trouble.

 

[Coaldust]

Pictures of the carnage would help

 

[92U 3406]

Cavitation of pumps is normally the result of a restricted inlet. Was the reservoir holding pressure? What about the suction screen, not plugged up?