Bobcat 753 hydraulic oil suddenly low?

   / Bobcat 753 hydraulic oil suddenly low? #1  

dieselfuelonly

Gold Member
Joined
Aug 13, 2007
Messages
332
Location
Chapel Hill, North Carolina
Tractor
Yanmar YM1401D
So, I was about to fire up my Bobcat today. I haven't used it in about 3 weeks, so I was even more religious in checking all the fluid levels before I started it up. I added about 4 gallons of diesel fuel, oil level is fine, but when I got to the hydraulic fluid - the dipstick was almost completely dry, with maybe a drop sticking to the bottom of the stick.

Before when I've checked the hydraulic fluid its always read about halfway up into the "safe" zone level on the stick. I don't see where several gallons of hydraulic fluid could have gone, unless its possible for it to slowly settle back down into the system?!?
 
   / Bobcat 753 hydraulic oil suddenly low? #2  
Was the boom UP by any chance?
 
   / Bobcat 753 hydraulic oil suddenly low? #3  
Hmm.. I don't know how much hyd oil your 753 takes but I'd guess that it's gotta be 5-6 gallons at least.

So, at the bottom of the dipstick.. you're probably a gallon low. If that's the case, I'd also think you'd have to see something somewhere on the machine; leaking.

I'd be hunting for a good steam cleaner to rent or borrow and do a thorough cleaning of the machine and start looking around for the source of the disappearing hyd fluid.

Best of luck.

AKfish
 
   / Bobcat 753 hydraulic oil suddenly low?
  • Thread Starter
#4  
Was the boom UP by any chance?

Nope. Boom down, bucket lowered. I just can't figure out where the oil would have gone!

Here's pretty much the extent of its use over the past month and a half. It was in the garage. Noticed a small puddle of oil about the size of a pancake below the machine. The spot was "dry" though, just the left over residue. I figured it was just the oil that I spilled over on to the other side of the engine when filling (which I think it was). Before using it I checked the hydraulic oil level and it was fine. Fired it up and messed around with positioning it and my Yanmar on the trailer. It was probably running a total of 20 minutes. Later on, I started it back up and parked it in the barn. Never noticed any leaks while operating it.

Fast forward to today, I check the hydraulic fluid level and its low! No sign of a hydraulic leak other than the same puddle that was in the garage, that I'm pretty sure is the rest of the spilled engine oil. I put a piece of cardboard under where I think the oil was coming from, and haven't seen a drop in several hours.

I just find it really weird that all of the sudden I'm low on oil, when I really haven't done anything, and there are no apparent leaks.
 
   / Bobcat 753 hydraulic oil suddenly low? #5  
Take the chaincase oil level plug out, you will find the missing oil.
 
   / Bobcat 753 hydraulic oil suddenly low? #6  
Take the chaincase oil level plug out, you will find the missing oil.


When he finds excessive oil in there what does he do? Where is the leak? How big of an ordeal is the repair?
 
   / Bobcat 753 hydraulic oil suddenly low? #7  
Drive motor and/or carrier seals leaking, bad thing about it theres no way to tell which side unless he finds bad bearings on one carrier when he takes the middle inspection plate off. Big repair, all chains off, drive motors and carriers off both sides.
 
   / Bobcat 753 hydraulic oil suddenly low?
  • Thread Starter
#8  
Any idea where this plug is on my machine so I can check it out? Thanks.

[EDIT]

This was an interesting read:

Accurate Machinery, LLC - Check that skid steer loader drive line!

I have seen some chain boxes that were over filled with oil. In this case, it is because the drive motor seal failed and the oil from the hydrostatic drive motor filled the chain case. The owner of this machine should have noticed that the hydraulic oil level had dropped but didn稚 know where it went, because the chain case can hold about five gallons of oil. 擢ire the son of a gun that is siphoning the oil out of my machine! 徹h sorry Ralph, you can come back to work, we found the lost oil in the chain case, but you lost your profit sharing? The unsuspecting purchaser of this machine will get a surprise one day because the oil will start spewing out of the machine. The overfilled chain box will leak through a chain case breather hole or a blown axle seal.

Sounds exactly like my problem and the symptoms I described, including the "someones siphoning out my oil!"

Well, no need to sit here and be pissed over it. You say it is an expensive repair - is it expensive labor wise, parts wise, or both? I'm not afraid to get my hands dirty at all.
 
   / Bobcat 753 hydraulic oil suddenly low? #9  
It's easiest got to with the boom arms up but it's on the front of the machine where you climb over in, down low and center think it takes a 1" wrench or socket. With the machine sitting level you should be able to remove plug and with a finger touch the oil level in the case, if oil starts gushing out when you take the plug out, you found your problem.
 
   / Bobcat 753 hydraulic oil suddenly low? #10  
Sounds exactly like my problem and the symptoms I described, including the "someones siphoning out my oil!"

Well, no need to sit here and be pissed over it. You say it is an expensive repair - is it expensive labor wise, parts wise, or both? I'm not afraid to get my hands dirty at all.[/QUOTE]

Sorry I didn't read the entire post before I replied. Far more labor wise than parts wise unless you happen to find something other than a bad seal. I cant remember the exact setup a 753 has on some Bobcat I remember it is possible to replace the seal thru the side cover after removing the drive motor or if not, unless someone has done the chains before and had put master links in and if you dont want to cut the chains and use master's then the axles have to come out a bit in order to get the chains off. If you go this way I strongly recommend axle bearings and seals. I can walk you thru it if need be but the Bobcat service manuals are usually less than $100.
 
 
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