On Fri, 02 Oct 2015 08:54:55 -0700, wrote:

On Wed, 30 Sep 2015 22:08:37 -0700, Larry Jaques
wrote:

On Wed, 30 Sep 2015 17:03:31 -0700, wrote:

I am going to be replacing the hydraulic pump on my Case 580 CK
backhoe this winter. Some time back the hydraulics heat exchanger in
the radiator leaked. This leak led to lots of oil in the water and a
some water in the oil. I fixed the problem by bypassing the internal
heat exchanger and then drained the coolant and hydraulic oil from the
machine. So after new coolant, new oil filters, and new hydraulic oil
all seemed well. After a few years the oil pressure dropped, a gradual
process, to the point where I knew there was a problem. It turns out
the pump is worn out. Checking the pressure where the Case manual says
to check it affirmed my suspicion that the pump is worn. So it will
either be repaired by me or replaced. It also turns out that I did not
get all the water out of the hydraulics. I think this may be why the
pump wore out. Even though the oil looked clear after I drained and
refilled the system I apparently didn't do it right because now the
oil is milky. There is no way for water to enter the system now except
by through the breathers and I run the machine long enough to get the
oil hot enough that this shouldn't be a problem. Speaking with my
neighbor who is a retired backhoe operator who owned his own business
about this I was told that I did not get all the water out the first
time and that this was not unusual. Especially for someone with my
limited experience. So to avoid ruining a new pump I have a plan and
need advice.
First I will replace the filters (there are only two).
Second I will drain and replace the hydraulic oil.
Third I will replace the pump.
Fourth will be bleeding the system.
The advice I need is how to be sure I get all the water out of the
hydraulic system, how best to bleed the system, and is my order of
operations above correct? Should I try to get the system water free
before I change the filters? Or should I do as above but then change
the filters again after changing the oil and making sure it is free of
water?

Have you called Case repair shop or corporate headquarters to find out
how they do it, or what they recommend?

My background isn't hydraulics, and I've never done one, but
experience tells me that I'd probably want to:

1- start it up to temperature and get the hydraulic oil hot, then
cycle through every single possible action to run oil through each and
every circuit.

2- then I'd disconnect every single line and blow each one out,

3- then R&R the cylinders and cycle them with the exhaust port down,
(dual actions flipped end to end to accomplish that)

4- remove the filter and blow that circuit out

5- R&R the tank and do the same, etc. If I couldn't remove the tank,
I'd find a way to angle it so I could get a hose down to the bottom
corner and siphon the last of the liquids out of it.

6- replace the pump, add new filter(s), fill with oil,

7- bring it up to temperature, and start running it through the
motions to get fresh oil in every circuit.

I'd think many are self-bleeding, but if not, try to cycle it with the
exhaust port as close to vertical as possible. Having disconnected
each fitting, you'll know which lines are what. I'd diagram all of
those circuits, too, for future reference, if it's not in the manual.

But the call to Case would be my first step. Perhaps ask local
rebuilders and operators for their advice, too. An old friend (the
best swamp dozer, belly scraper, and backhoe operator I've ever met, a
real -natural-) would be happy to relate that to me, but I lost track
of Jeff a couple decades ago. Sorry.
I have not called Case yet. The last time I spoke with the Case guys
they were reluctant to help with such a small time guy like me. But I

Jeeze, it's a shame to hear that. WTF happened to American customer
service? /rhetorical question sigh


will give them a call. I will not be taking any cylinders apart but I
can remove the lines from each and blow them out. Fortunately there is
a drain at the bottom of each oil reservoir, as the reservoirs are
part of the frame of the machine.

In thinking about vacuum, I'm wondering what the lines are able to
withstand, too. 28" isn't full hard vacuum, but it's awful close.

--
The human brain is unique in that it is the only container of which
it can be said that the more you put into it, the more it will hold.
-- Glenn Doman