Bobcat 753 Hydraulic leaking from reservoir Cap

Bobcatdan said:

Its over filled or the something isn't right with the breather cap. The tank is not pressurized. The system does build a tiny about of pressure from heat, but that's it.

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bigmcshawn said:

The bucket hydraulic cylinder is leaking a little bit when extended all the way out! and making a suction noise at the very end of retracting back in. Could that allowed air into my system and creating a problem? The bobcat dealer replaced the breather cap.When taking the lift up! I can see the fluid coming out of the cap, And when letting the lift back down the fluid is sucking back into the cap! What I don't know is there some type of one-way valve under the breather cap? I probably lost a couple gallons of hydraulic fluid, Could it have been that overfilled by the Bobcat dealer? I spent $1400 To have my Bobcat dealer go completely through the Machine an fixed whatever needed to be fixed! However: Once I got back to my shop I discovered that it had a froze up cooling belt tensioner and a very badly cracked drive belt. I replaced both of them. Sense I felt like that should've been bobcat mechanic diagnosing 101! I do not feel like I can trust my local Bobcat service center to solve the problem! So, any help would be greatly appreciated!!!!

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reed2022 said:

With its sucking on the uplift and blowing on down stroke this says over full on hydraulic reservoir.

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bigmcshawn said:

I am checking right now to see if it its sucking on the uplift and blowing on the down stroke! if so, should I just run the machine for a while to see if the problem clears up? the overflow does not seem to affect anything an the hydraulics are working with good response times!

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Bobcatdan said:

The level of fluid in the tank goes down as cylinders are extended. With the boom up, the fluid is at is lowest point. It is at its fullest with boom down bucket curled all the way back. That is when you check hydraulic fluid level.

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reed2022 said:

Dan is right about fluid going up and down when cylinder are extended and retracted. To check you hydrualic fluid level bucket should be flat on ground and lift cylinders should be down. The hydrualic oil should be cool and then look at your site glass the hydrualic oil should be at the full mark. If you have to two valves on left side of tank it should between the bottom valve and the top valve when cold because the oil expands when hot.

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bigmcshawn said:

is there a site glass on the Bobcat 753? If so where is it! all I can find is a Dipstick next to the hydraulics filler cap! Every other piece of machinery I own has a hydraulic sight glass!

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bigmcshawn said:

With boom down bucket flat on the ground and hydraulic fluid cold it registered about halfway on the dip stick! I really do appreciate everyone's help! Is there anything else I can check?

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reed2022 said:

I did some checking and I was wrong bobcat Dan is Right the bucket should be tilted back to check fluid level. That may be enough to put the reservoir over full. If that is not the problem your cap may be bad even If it is new.

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bigmcshawn said:

I'm at a loss! Everything works good but hydraulic fluid blows out around both caps and the dip stick on the reservoir tank. Bobcat just perform a 1000 hr replaced all hydraulic filters but one, looks like they did not replace one in line filter under the seat they replace the in line filter at the reservoir. Should they have replaced the hydraulic line filter under the seat? the one underneath the left hand side of the seat just before it gets to the hydraulic pump?

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Bobcatdan said:

There is one filter for each drive motor so yes, both should have been changed. Not changing one should not be causing your problem. Normally there is very little pressure since they are simple drains. Higher pressure from a case drain would indicate a drive motor failing.

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bigmcshawn said:

turned out the pressure is OK! Should I try a different type of hydraulic fluid than the one bobcat put in? If so what would you recommend?

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bigmcshawn said:

Hello I recently picked up a 1999 Bobcat 753 with 1811 HRS, On the day I bought it I decided to take it to my local bobcat dealer for a good look over, before putting it to work. A course they came up with some issues that needed to be fixed! now after paying a large sum of money for a clean bill of health! Everything seems to function as it should with the exception of one problem Hydraulic fluid is blowing out thru the vents in the filler cap! It only seems to happen when lifting and lowering the boom. below is a list of the things the Bobcat dealers fix! Installed new seat bar sensor and bushings. Installed new hydraulic lock stem, o rings, coil and nut. resealed lift & tilt spools inside control valve, new boots with o-rings. No other leaks at this time. Changed engine oil, all filters. changed hydraulic cap, gasket and changed hydraulic oil. I don't know if I should take it back my local bobcat dealer? Please tell me could any of the repairs that they perform have anything to do with my current problem?

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TylerAW said:

Do you have any updates on your issue and if/what resolved it? Im having the same issue and I narrowed it down to raising and lowering the boom to triggering it

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cdmccul said:

Do you also have a seeping tilt cylinder?

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