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?
Thanks,
Eric