backhoe complete hydraulic purge procedure
bigdanallan
Join Date: Sep 2010 Posts: 2 juneau, alaska |
2010-09-07 173792
i need to completely purge my hydraulic system on 1974 case 780 backhoe. oil is water contaminated. the system holds 45 gal what is the best method to use the least new oil? my plan is drain tank, refill. connect return hose to used barrel, extend each ram system fully out as fast as possible. shut down. let all rams possible freefall to the down cylinder position to drain. refill. start up. extend again, each direction. shut down. hook up return hose. refill. DONE. can i cause any damage to cylinders by extending fully while oil is not returning to tank(used contaminated to barrel)being careful not to run main pump dry. other things to be careful of? is there a standard procedure for this job?? thanks. dan
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backhoe complete hydraulic purge procedure
hardwood
Join Date: Dec 2002 Posts: 3583 iowa |
2010-09-07 173795
Bigdan;
I don't think you will damage the cylinders by doing as you describe.
It does sound like you shouldn't wear your Sunday best while doing this tho.
It may take quite a while to work the air out of the system when you're done.
Frank. ....
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backhoe complete hydraulic purge procedure
Murf
Join Date: Dec 1999 Posts: 7249 Toronto Area, Ontario, Canada Pics |
2010-09-07 173801
Any time we need to completely clean all the old fluid out of anything we use air. It's far more economical and doesn't result in huge amounts of contaminated fluid.
We start with an adapter on the main line out of the pump and introduce the air there. Then using a combination of repetitive cycling and a bungee cord to hold the valve open, start draining cylinders by retracting them manually (come-alongs, winches, straps, etc.) and clearing the lines by cracking them and allowing the air flow to blow out the used oil. A stout rag tied over the end of the line both collects the spatter into a single flow, but also shows you any debris that came out as well.
It's a long fussy job, but about the only way. Just a little of the old fluid will contaminate a whole lot of new fluid.
Best of luck. ....
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