I am looking for some history of experiences with charge  pumps / Hydraulic pumps going bad. I was having a very interesting conversation about this topic today. Concretepumping.com is the place for this discussion.

Thanks,

Seed    

seed r u talking about the pumps that are bolted to the drive box under the sub frame? if so got tons of experince with that

For those that wish to know

http://www.poclain-hydraulics.com/portals/0/self%20training/Closed%20Loop%20pump.pdf

A basic closed loop pump

Now all the Alliance, Concord and KCP customers are having a good chuckle because they do not have that cheesy charge pump to deal with. When you have $20,000.00 worth of hydraulic pumps rotating in your crete pump, the last thing you need is a $.25 charge pump to say whether it all lives or dies. Lets all hear it for open loop systems; come on Schwing, take a bow, you were there first.

thank u bob

Our experiences with charge pump failures are normally due to suction filter failure, that is either blocked due to not been replaced on a regular basis (250 to 300 hrs) cheap after market filters ........ undersized suction hose(s) or poor oil tank design.

DIGGER

My favorite feature of the Jun-Jin machines is the positive air charge inside the oil tank. Now there is a charge pump!

IF everyone performed their filter change out BEFORE it was needed; charge pumps would be less of a problem.

Have you ever considered changing the charge pump as a means to increasing the life of the main pump? Like a preventive maint' item? Does anyone have a schedule for doing an R&R on the charge pump? Should you?

bob

i thought charge pumps were only found in a closed loop circuit, jun jin is open circuit.

i also thought that a charge pump's job was just to replentish any lost oil thru slippage to keep the circuit full.

"daewoo", closed loop, 2 x 125cc pumps= 2 suction ports, no air assistance.

"jun jin", open circuit, 1 x 250cc pump= 1 very very long suction port with air assistance.

does not matter which brand or which circuit, if you dont do the maintenance, you are going to be bitten on the bum eventually.

i am not an admirer of the air charged hydraulic tank for several reasons.

hey digger, is that one of your machines with todd's dial (superimposed) on the splash board or is he giving J or F a plug?

I am under the assumption. As long as regular maintenance and filter changes are done at proper scheduling. You should be fine. Sh#! happens!  Maintenance PRICELESS!

Thanks,

Bob!

Seed,

I am curious about what Putz says about changing the charge pump as a preventive measure. Repeated cold starts where you live might take a toll... I do not know.

wouldnt the same cold starts effect the main pump as well over time, how cold does it get there?  clean filters or dirty filters, cavitation is a big killer.

Seed

Did you ever call Putz?

It has been a log day Bob. I will and I will let you know what I find  out!

on the subject of charge pump/hydraulic pump failure on closed loop systems: i refer you to the diminsion on the filter retainer bolt and nut that you screw the filter off of (putz) if this diminsion is changed , when you install the new filter in the machine the tank check valves are not opening all the way.