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Mc 28 Hydraulic oil overflowing
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Author:  PhilSask [ January 19th, 2010, 12:33 pm ]
Post subject:  Mc 28 Hydraulic oil overflowing


We have a 28 for several years.

The hydraulic oil is overflowing from the filler cap after operating for an hour or more.

It was only filled to the oil lens level and the oil was recently replaced twice as it was contaminated with water, the procedure to bleed air was followed as in the manual.

The oil is Univas 22.

May or may not be related,
I had to crank the hydraulic oil flow adjustment screw just enough when doing 8" Dr 11 as the facer was stalling when facing on only slight carriage pressure.

In your other posts, how would you determine if the facer hydraulic pump is starting to fail?

Any idears?
Thanks in advance

Author:  Joshua [ January 19th, 2010, 3:50 pm ]
Post subject:  Re: Mc 28 Hydraulic oil overflowing

That is an interesting combination of issues.

I would first point out that there is not a hydraulic oil adjustment screw. That adjusts the shift point between high flow low/low pressure and high pressure/low flow modes. I would start by adjusting this back as is should. The system should be relieved at 900 PSI. It should be at 300 PSI when the facer is running.

Once that is corrected, check the system flow. Plumb a flow meter in place of the facer. The pump should be putting out 5 GPM.

Once you have verified that the hydraulic pump is working and set up properly, check the facer again. If it stalls without trying to face with excessive pressure that may be an indication of an issue.

The first issue that I have seen cause this is the force that the facer motor is putting out (bad motor).

The second issue is that the machine has trouble cutting. This could be dull or chipped blades or a bent blade holder, etc.

I do find it interesting that the hydraulic tank is overflowing even though it is only filled to the lens. The first thing that comes to mind here is heat. The reason that we don't fill the units to the top is that the oil expands as it heats up. The lens is located such that it should not overflow under normal conditions. I would be very interested to know what the temperature of the oil is when the unit overflows. I am wondering if there is some hydraulic condition that is making the unit overheat and cause excessive expansion of the oil. You can do a kind of hillbilly check by touching the tank or relief manifold when this issue is occurring. Obviously you will want to take precautions to ensure that you do not get burned if this is the situation.
The most common source of heat that I have seen is something bypassing or something is working harder than it should be.
How many amps does the machine pull when the facer is on and when the machine is running without any of the actuators moving?

Author:  PhilSask [ January 22nd, 2010, 3:11 pm ]
Post subject:  Re: Mc 28 Hydraulic oil overflowing

Hay Josh

I have yet to get a flow meter so will do that next week.

I adjusted the shift point screw under the acorn nut back to where it was.

The oil takes about 1 1/2 hours to overflow with normal usage ( facing and fusing ), the temp of the oil is 133F with an infared gun and 140 F with a thermometer when overlowing, it looks like normal oil.

Amps using a ring cord multimeter,
0.02 when plugged in
0.73 with motor running and nothing else
0.72 - 0.97 when the carriage closes at fusion pressure
0.62 when facer is going
0.62 - 0.97 with facer and carriage at just enough pressure to face.

Any idears,

Thanks Phil

Author:  TOOLDADY [ January 22nd, 2010, 6:19 pm ]
Post subject:  Re: Mc 28 Hydraulic oil overflowing

I have had the same problem with hydraulic oil over heating and over flowing on a 28 and others also, after working on the machine for awhile trying to figure it out, I found a hydraulic line quick disconect that was not opening totally when put togethter, this was causing friction and making the oil over heat. I would suggest doing the test that Josh is telling you about first then try replacing the quick disconects and see if that helps, trust me it is all trial and error to find the problem somtimes.

Good luck, Tooldady

Author:  PhilSask [ March 8th, 2010, 10:33 am ]
Post subject:  Re: Mc 28 Hydraulic oil overflowing

Hi Guys

Thanks for the responce.

Do you know the flow meter model number / manufacturer that you have used.

No one round here seems to know or replies to enquiries.

Thanks phil

Author:  Joshua [ March 8th, 2010, 12:00 pm ]
Post subject:  Re: Mc 28 Hydraulic oil overflowing

Our part number is MEP00014. That is the one that I have. That one or something close should work nicely. You can type that number into the parts finder and it will show you a picture of it.

Author:  PhilSask [ November 24th, 2010, 11:12 am ]
Post subject:  Re: Mc 28 Hydraulic oil overflowing


We done all that, the flow meter shows 5gpm when attached to the facer / replace the facer, and drops to 3gpm under facer load of 8"dr11.

The funny thing is the new machine is stalling as well but the oil level stays ok, the hydraulic pump gets just as hot on the new and old one, maybe the 28 needs more power for the facer, blades are fairley new. :?

ON the old machine the oil is starting to look cloudy so it could be contaminated afterall.

We just received a 412 from McElroy, we did basic testing on it and the heater got up to temp etc, seemed ok.
The cust called and said the oil is overflowing, we see what transpires if he brings it back, I guess check the same things when it comes back before doing a RM? :?

Thanks Phil

Author:  tulsamurph [ November 29th, 2010, 9:04 am ]
Post subject:  Re: Mc 28 Hydraulic oil overflowing


On the 28, you mentioned a Univis 22; the machines are shipped with Univis 46. Unless it is very cold where you are, it seems that the oil may be too thin. I may be missing some piece of information, but a heavier oil might be a step in the right direction.

Keep us posted,

Author:  PhilSask [ December 13th, 2010, 4:05 pm ]
Post subject:  Re: Mc 28 Hydraulic oil overflowing

Hi John

Yup, it goes down to -30c or less :shock: here, I guess a lighter oil that Univar 46 would do.

The problem would be when it is transported on back of a truck to the site and then expect it to work within a couple of hours, even with a heated canopy, the oil still would be ambient temp.

But would that thin oil expand in summer? The ideal would be to change it in sommer to Uv46?


Author:  tulsamurph [ December 14th, 2010, 9:53 am ]
Post subject:  Re: Mc 28 Hydraulic oil overflowing

The hydraulic oil chart in the back of our catalog has some recommended fluids for various temperature ranges, but there is a point where if you need a machine to work in very hot environments in the summer, and very cold environments in the winter, you may have to switch fluids.

A synthetic oil may help with your cold climate flow, but it still needs to be a hydraulic fluid with an ISO rating equivalent to the recommended fluids in our catalog. There might be some synthetics available with a wider temperature range of operation, however synthetic can be quite a bit more expensive, maybe more so than changing fluids twice a year.


Author:  tulsamurph [ December 14th, 2010, 9:58 am ]
Post subject:  Re: Mc 28 Hydraulic oil overflowing

Just to make sure we don't lose track of the original problem, is the machine still overflowing? Since the fluid is starting to look cloudy, are your plans to change the oil and see if all is now on track? Sounds like the new facer motor could have been a significant chunk of the problem, with the contamination the remainder.

Let us know where you stand, and we will keep at it until we solve the issue.


Author:  tulsamurph [ December 14th, 2010, 6:35 pm ]
Post subject:  Re: Mc 28 Hydraulic oil overflowing


One question, what is your system pressure set at? It should be 900 psi with carriage disconnected and facer valve closed. If it is significantly different, it could cause excessive heat. When you plug in the carriage, and the jaws are not moving, the pressure should stay the same. With facer running, you should see a drop in pressure to approximately 300 psi or so.


Author:  Murray Sullivan [ July 26th, 2012, 4:32 pm ]
Post subject:  Re: Mc 28 Hydraulic oil overflowing

Check for a loose fitting, they will suck in air and cause a overflowing problem.

Author:  ssharpsteen [ April 19th, 2013, 2:51 pm ]
Post subject:  Re: Mc 28 Hydraulic oil overflowing

Sorry to join the party so late but i came across my first one of these this week. 04/19/13. I tryed every thing above plus some! this was an older hyd facer 28 with 1/4 in hyd lines going from the manifold to the facer to the tank. after trying everything i could think of i could only get it to flow 3.5 gpm. so i decided to change those two hoses after removing them i found that even though the od of the hoses looked the same when it came to the id of them the hole on one of them was half the size. I had two new hoses made making sure of the proper inside diameter. 5 gpm now and no overflowing. ( wouldent be it nice if when someone brings you something like that. they would tell you its been doing that since i changed that hose, what a day. going home and have a beer see ya)

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