IH3200B losing hydraulic fluid from breather

[5030tinkerer]

I have 70's IH3200B skid steer. Since I have had it, it has pushed hydraulic fluid out of the top-mounted reservoir breather when I lower the bucket anything other than very, very slowly. /forums/images/graemlins/mad.gif The full line on the dipstick results in the fluid level being very close to the top of the reservoir. Thinking that perhaps it was not the correct dipstick, I allowed the fluid level to drop (by not refilling the reservoir when it would dump fluid out of the breather) so that the reservoir leak would not happen so frequently. This resulted in a noticable loss of loader lift. The fluid itself is not milky in the reservoir. I have been through the entire machine and replaced all of the orings and hoses throughout (had numerous leaks in other areas before).

Does anyone have any other ideas as to what could be wrong? /forums/images/graemlins/confused.gif

 

[5030tinkerer]

Okay, hearing no ideas...what does everyone think of my "solution" to use a 3" or so diameter PVC pipe perhaps 12" long capped at each end to serve as an auxiliary hydraulic tank? I'd remove the current breather from the "main" tank, create threads in the PVC to accept the breather, attach it, and then plumb between the current tank and the new "tank". This would create maybe a two quart space for the hydraulic fluid that would have spilled out the breather in its old location to go and still allow the system to breathe. Could this work? I've already found an acceptable mounting location for the new "tank" if so. Any concerns about the hydraulic fluid reacting with the PVC or PVC cement? /forums/images/graemlins/confused.gif

 

[normde2001]

I don't know anything about that machine, but there are a ton of things I would try before trying to work around the problem and possibly destroying the hydraulic pump. For the fluid to overflow, it obviously is not returning to the pump correctly, either from a plugged vent or a clogged pickup return filter, etc. An ops/service/parts manual would probably show this, or probably there is help on a Case-IH forum.

 

[MadReferee]

You might get a better response if you asked your question in one of the IH forums. The Red Power IHC forums are dedicated to the older IH equipment and are very active.

Red Power IHC forums

 

[turnkey4099]

Can't help with the solving the problem. Using PVC as aux tank? Can't see any problem but would use CPVC. PVC softens with heat, CPVC doesn't.

Harry K

 

[5030tinkerer]

Thanks for the replies, guys. I was not aware of the Red Power Magazine forum and have re-posted this question there. Thanks!

Some additional information: The fluid is overflowing from the reservoir tank. There are several supply and one return line to/from the reservoir. The rubber return line has been replaced along with all of the rubber pressure supply lines and the various o-rings at the connections. The o-rings were replaced from IH-dealer provided rings specified for this machine (same hardness rating). The only hydraulic filter my manuals show is inside the reservoir tank. I replaced this filter as part of the major parts replacement project that I referenced in my initial post. I have the ops, service, and parts manuals. They don’t show anything hydraulics-plumbing related (other than the metal high-pressure supply lines) that I have not replaced.

The only vent that I am aware of is this one that is overflowing. I can tell you that when the fluid starts coming out, it does so as a result of pressurization of the reservoir tank. When it happens, it will go for 15 – 20 seconds before stopping; about a ½ to a full quart of fluid is lost each time. If I remove the hydraulic filler cap during one of these sessions, the overflow immediately stops. Basically, removing the filler cap allows the tank to de-pressurize (the filler cap makes a popping noise when it comes off, a lot like opening a bottle of champagne. This noise is NOT heard when the unit is not having an overflow). Air can be heard escaping the breather when I lower the loader slowly. The air changes to fluid when I lower the loader more quickly.

It should be a zero-pressure system. The breather is supposed to keep it that way. I did note that when the unit is on a level surface, powered off, and the hydraulic level is to the “full” line on the dipstick, the oil level is barely under (like an inch or less) the bottom edge of the breather (noted this as a result of taking off the breather, exposing the 3/8” tank opening).


“For the fluid to overflow, it obviously is not returning to the pump correctly, either from a plugged vent or a clogged pickup return filter, etc.”

While writing this, I re-read Norm’s comment about the possibility of something being plugged. I have never heard of such a thing, but is it possible that my metal supply line leaving the hydraulic tank and feeding the loader hydraulic pump is partially plugged (likely from inadequate hydraulic filter change intervals by the prior owner) and that when I lower my bucket too fast, so much extra hydraulic fluid is attempting to re-enter my tank at once (after all, the return line is somewhere around 1 1/8” and each of my two hydraulic loader cylinders are three inch diameter or so) that the supply line cannot keep up with getting the fluid back to the hydraulic loader pump in time to prevent the tank from overfilling and pressurizing, thus forcing the fluid the only place it can go (the breather vent) and causing my pump to be forced to run dry? Is that what you meant, Norm?

Are there typically vents/screens inside the hydraulic pumps or anywhere else on the supply side? My manuals don't show any, but I suppose it's possible that they do exist and one or more of them is plugged. One of the drive pumps had been replaced by the prior owner. The other two pumps are original (there is a pump for the left wheels, the right wheels, and the loader). No clue on the service history outside of that. Maybe a good course of action would be drain the hydraulic tank (oh joy), remove the supply line feeding the loader hydraulic pump, and check it for a blockage. If I don't find one, perhaps the next step would be to remove the loader hydraulic pump and inspect it for a clogged input screen (possibly by taking it apart – more joy). If that isn't it, I’m not terribly sure what is left. Note that starting and stopping suddenly does NOT cause this problem, nor does spinning the skid steer full left or full right and then coming to a quick halt (this leading me to believe that the supply blockage, if that is what the problem is, is not an issue for either of the hydraulic drive pumps).

Any other thoughts before I spend ANOTHER 20 hours or more on this? Am I likely on the right track (if so, a HUGE thank you to Norm for the idea)?

Ed

 

[CT_Tree_Guy]

Ed, all I can think of at this late hour is that the breather itself might be restricted. If the reservoir is becoming pressurized when you lower the loader quickly, but less so when you lower it slowly, it might just be a simple matter of a faulty breather. Have you tried operating the loader with the breather completely removed?

Sorry, that's all I've got at the moment, with the possible exception of a faulty spool valve that's allowing hydraulic oil to flow where it's not supposed to, or not flow where it IS supposed to. I once blew up a perfectly good boom-mounted hydraulic winch that way, when I swapped in a spool valve that wasn't ported the same way as one that looked absolutely identical from the outside. Maybe take that loader valve apart and look for a hopelessly clogged port.

Hope this helps, John

 

[JerryG]

<font color="blue"> The fluid itself is not milky in the reservoir. </font>
Have you looked at it close? Does it have very, very small air bubbles in it?

 

[5030tinkerer]

Nope. No bubbles. The folks at Red Power have opined that possibly I should have had a breather on my fill tube instead of the sealed tube that I currently have. It was also suggested that my tank breather should not be open air, but rather include a spring that ensures that only air is let through, not hydraulic oil. I'll be chatting with the local IH/Case dealer to see about picking up these items next week - hopefully they'll be able to get these items.