Cat 325L no hydraulic power

[rclay1981]

I've got a cat 325l long reach with app 10000 hrs on it serial# 6KK0012K
It started out with no power and a hydraulic chatter noise while raising the boom the other functions seamed normal. I checked pump psi both were around 4000 psi so i tested pressures at boom cylinder and it was about the same but while working the machine it lost hydraulic power to all functions. Boom up is only 1800 psi, boom down 900 psi at the cylinders.
Checking the pumps pressures they are low all the time. I flipped over ride switch and it didn't make difference.
Thanks for the help

 

[mikebramel]

Sounds like you lost a piston

 

[mikebramel]

Pumps were probably cavitating giving you warning

 

[John C.]

Pull the suction strainer in the hydraulic tank. I've heard the kind of noise you describe on a machine a leaf licker poured dirt into.

 

[rclay1981]

I’m assuming You mean a piston in the pump.

 

[mikebramel]

Yes. But check the strainer likeJohn said

 

[DEMLONE70]

Check first filters

 

[rclay1981]

Filters have Approximately 20 hours on them

 

[DEMLONE70]

20 hours ago the pressure was ok now its bad so filters can be contaminated

 

[r20d12]

So the filters were changed. Then it started messing up?

 

[rclay1981]

The customer changed the hyd oil and filters and have app 20 hours on them.

Does anyone have the procedure for checking and adjusting the prv valve?

 

[TVA]

Is there any chance that customer also drained oil out of pumps and didn’t fill pumps back at the recommissioning?

 

[rclay1981]

I wouldn’t think so. But I don’t know for sure

 

[rclay1981]

I did find out some prior history of the machine before my customers got it. It’s had numerous different hydraulic problems and it’s had 2 PRV valves put on it in the last 2 years the Pump was supposed to of been rebuilt three years ago

 

[TVA]

Hey CAT guys, is there a ways to tap in to suction line to mesure vacuum on that machine?

 

[r20d12]

Piston pumps can't "suck" the oil is pushed into the supply side by atmospheric pressure. You made me think of something! I think this model has an air pump that pressurizes the tank to help feed the pump. If it has failed then that would have explained the pump cavitation sounds when you called for max flow. Due to the air pump failure though. It sounds like the main pump ate its self.

 

[TVA]

I didn’t know about air pump, I always thought that tank pressure was building up by system heating up and by case drains.

 

[TVA]

On the other thread, chap from Oz. Found what killed his pump - rag in the tank!
And gat this - Daikin pump on the CAT excavator! I don’t think we have those here for n US! Only Daikin I know is refrigeration equipment!

 

[r20d12]

On the other thread, chap from Oz. Found what killed his pump - rag in the tank!
And gat this - Daikin pump on the CAT excavator! I don’t think we have those here for n US! Only Daikin I know is refrigeration equipment!

I can't find the thread!? Rags can be quite troublesome!

 

[TVA]

I can't find the thread!? Rags can be quite troublesome!

It’s a CAT E140 thread.