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bought an 843. Bad oil leak through chain case breather.
If it's coming out of there, your chain case is over full. A drive motor is leaking into the chain case past the seals.
bad bearings in gearbox. Blowing fluid into chain case.. Rebuilt, bearings & races, quad & outer seals. Resealed motor. 1st time inner & outer seals on balance plate only, rest of motor seemed 'ok', no external leaks, valve, geroler, drive, all clean no visible wear. Fired up, same leak, pumping hyd fluid thru the 'weep hole' from gear box. Looking for something 'blown', grbx seal looked good externally. Disassembled motor, all looked good except for small o-ring (case drain?) between geroler & mounting flange plate indented in, towards ID/passage. Large o-ring showed no signs of leaking, just 'flat', original looking. Replaced all seals. Checked shuttle valve. Looked clean, slight 'spring'wear marks on what Bobcat is calling a 'shuttle'. I'm 98% sure the shuttle was touching the plug, inserted into the end of the spring. I have an exploded view of an Eaton Char-Lynn Series 6000 motor shuttle valve showing the same parts orientation except they call the shuttle a 'dash pot'. However Bobcat manual shows the spring & shuttle 'flopped', meaning from the center out, the parts are as: piston, poppet, shuttle, spring, then plug. I believed shuttle valve is to relieve pressure/protect seals, so I installed as manual said. Also checked case drain orifice for blockage and changed out hydrostatic oil filter. Thought that any trouble there would affect both motors though. Fired it up, same stink'in leak!! continued....
Wow, you're fast replying. I don't type that fast, but there is more to come.
1st thought is to replace quad & grbx seal (again), 2nd thought is to put the shuttle valve back to what i believed was the original order. Pulled plug & spring was flat and shuttle bent!? Does anyone see this as a clue to the motor leak? What is the proper/correct shuttle valve assembly? What is 'normal' case drain pressure? I hate to go buy a motor if I'm not positively sure that is the problem, and I'm not just missing something stupid. Is it possible to have a motor run/tested for proper operation? I'm running out of ideas & rope! Thanks ahead of time for any ideas/experience you might have in figuring out this problem. Sorry for the multiple 'posts', but this is the 4th time I've typed this out trying to explain all that's been done so far. Thanks again
The case drain should be no pressure.
If the shuttle valve wasn't working, the motor wouldn't work properly, i don't believe it would blow out the seals though.
This picture shows you the basic order, see the rings with the taper on them? then should face the centre of the rod, then a spring, then the stepped ring, then the plug.
Hopefully i have that order right, been a little while since i did one.
Tazza, Sorry for the late response, I just got back since original post. Like your picture shows, is how I believed mine originally came apart. However the 843 Bobcat manual showed the 'stepped ring' in 1st, then the spring, finally the plug. After starting machine & still having same leak, decided to put shuttle back in the order your picture shows, and the spring was flat and 'stepped ring' bent! Some serious pressure coming from somewhere! Now i'm attempting to get shuttle repair pieces to get it functional, and then hopefully find somebody that can bolt the motor into something, apply working pressure to it to verify it's either good or bad. I'd just like to be sure it is the motor that is the culprit. I'd be pretty ticked off at myself if I replaced the motor (for about a grand!) and find I have an issue with my gearbox and/or seals (they both appear smooth & tight, though). I've been fooling around quite awhile now and just want to be done 'guessing'. That's why I turned to the Forum, just in case someone else encountered a similar situation. I've gotten some good info off of the site in the past. Thanks for replying, I appreciate the input. I will keep you posted when I figure it out. Thanks again
Have you tried swapping motors from side to side? This way you know for usre if the issue is in the motor or not.
I understand your frustration
