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General help with a machine...

cchase

New Member
Joined
Jun 10, 2004
Messages
2
Location
NW WA
Recently bought a gray market excavator, which appears to be for the most part a good machine, but I have a hydraulic leak. Haven't found the source yet, but it appears that it may be coming from the control valves.

I don't have a lot of experience working on hydraulics, I understand the principal and how they work, but am looking for a source of information on the does and don'ts, like a Hydraulics for Dummies books. Anybody here know where I could find such a thing?

The excavator is supposedly an '83 Yanmar YB281X.
 
Last edited:

glsahl

Charter Member
Joined
Dec 13, 2003
Messages
84
Location
white settlement, tx
Occupation
equip.mngr/mechanic
Our Kobelco SK200LC has been notorious for leaking at the tubes coming out of the control valve.They have a compression fitting,with a very narrow ferrule.Machines vibration shakes the tube loose,and it backs out of the nut.Then,sure as the Sun shines in Vegas,an operator will overtighten the nut,this bottoms the end of the tube into the adapter,and fnishes off the ferrule.
If you watch the area,and have someone deadhead one circut at a time,most leaks will be happy to expose themselves.Just remember to stick the bucket in a trench when checking the swing circut,had a guy help me one time by lifting the tracks off the ground a foot,weight held the bucket,but he swiveled the tracks into a developer's truck.Considering the bath I got,he was almost reasonable.
 

cchase

New Member
Joined
Jun 10, 2004
Messages
2
Location
NW WA
Thanks for the advice. I found the leak, it is at the supply end of the valve block. It appears the previous owner stripped a fitting. Luckily access is fairly decent and it shouldn't be a major issue to replace.
 

mrexfix

Member
Joined
Jan 31, 2010
Messages
18
Location
australia victoria frankston
Thanks for the advice. I found the leak, it is at the supply end of the valve block. It appears the previous owner stripped a fitting. Luckily access is fairly decent and it shouldn't be a major issue to replace.
no book that i know of seen heaps of leaks fixed heaps of leaks easy way to find leaks is to wash machine well and regurly
 

AtlasRob

Senior Member
Joined
Feb 8, 2008
Messages
1,982
Location
West Sussex UK
Occupation
owner operator
I don't have a lot of experience working on hydraulics, I understand the principal and how they work, but am looking for a source of information on the does and don'ts,

Remember that the system needs the pressure releasing BEFORE you attempt to remove a pipe or fitting.
The easiest most common method on the smaller equipment is having stopped the machine, turn the key back on but not started. With the deadman lever down in work mode, gently move the control levers including the track levers back and forth to all possible positions. You will probably see the machine actually relax.
This is not a guarantee that all pressure is released. Extreme care must be taken when releasing any fittings. Always assume its still got pressure and expect a shower. Hopefully you will be disappointed :D
 
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