Custom hydraulic filters

[5030tinkerer]

Anyone know how to go about determining flow characteristics and associated filtering requirements for a given piece of equipment? I have an old Koehring 6620-LC5 (http://www.minnpar.com/partbooks/Koehring and Bantam/Excavators/6620-5-PARTS-1176001.pdf) excavator and parts are getting ridiculously expensive and hard to (and even impossible to) find. It took nearly six MONTHS to get the filters in for my last hydraulic filter change and no one seems to have a cross reference available. I've even thought about adding my own pre-filters upstream or just replacing the factory filtration mechanism.

I'd ideally just like to get filter cross reference numbers, but that failing, would look towards getting custom filters made and/or installing upstream filters.

In case it helps anyone else, here's what I have so far from the parts manual above:

Engine oil filter - Wix 51640 - 404 - Document Not Found
Engine fuel filter - Wix 33260 - 404 - Document Not Found
730 7189 Air filter, new number is 900V6875, CROSSES to Donaldson P181054 - P181054 - 900V6875 - AIR PRMY DONALDSON REPLACEMENT FOR KOEHRING 900V6875 P181054 Standard Version P182054 LONG LIFE VERSION P148968 High Pulsation - Filter Products
730 2707 Element (in tank?)
730 2860 O Ring for #31 element
730 0729 O Ring for #31 element
730 2865 O Ring for #21 element
730 4341 Filter assembly
730 7032 Strainer (likely not needed)
730 7020 O Ring for #21 element
730 2709 Filter ***'y, pilot
730 7043 Filter ***'y, swing
730 6198 Cartridge (spin on)
730 4869 Strainer, suction

Any ideas?

 

[oldnslo]

for replacement elements if you get the OD, ID, and length of your existing elements you might be able to find an interchange from companies like Schroeder Industries best fit, donaldson, Parker, Rexroth, Pall, etc.

For application info on filters here are some things that need to be considered:
Flow rate GPM
Oil viscosity
operating pressure in the line this will be installed in. Consider cyclic pressure if in a pressure line
mounting style or position: Filter bowl up, down, etc.
filtration level: I.e. micron rating or desired cleanliness
port type and location
Clogged filter indicator

 

[5030tinkerer]

for replacement elements if you get the OD, ID, and length of your existing elements you might be able to find an interchange from companies like Schroeder Industries best fit, donaldson, Parker, Rexroth, Pall, etc.

For application info on filters here are some things that need to be considered:
Flow rate GPM
Oil viscosity
operating pressure in the line this will be installed in. Consider cyclic pressure if in a pressure line
mounting style or position: Filter bowl up, down, etc.
filtration level: I.e. micron rating or desired cleanliness
port type and location
Clogged filter indicator

This is precisely the issue - I can't know some of these numbers (filtration level, flow rate in GPM, and cyclic pressure, as examples)

I am hanging onto my old filters during this change so that I can take measurements and surely that will help things, but I don't know how to determine flow characteristic requirements.

 

[oldnslo]

Where are the filters located in the system today? Pressure lines or return lines. You can use the existing filter element and bowl sizes as a starting point for replacement filters. Not sure what type of pumps and valves you have on that excavator but for gear pumps and manual valves a good 10 micron filter should be adequate. For piston pumps and proportional valves i would with 3 or 5 micron. Filter elements are significantly less expensive and easier to replace than pumps and control valves.

In Iowa companies like Iowa Fluid Power has service department that can help you determine what you have and recommend replacements.