International 1066, Hydrualics sucking Air

Good Day Everyone,

I have a international 1066 that seems as if the hydraulics are sucking air from somewhere. It seems as if its effecting both the main system and the MVC system. When you start the tractor everything works fine until you get it up too operation revs, 1500 or greater, than the steering, clutch and TA seems to stop working. It will even stop moving. Adding to this, if I try to raise the haybine, its very jerky and slow. When I undo the connections I do see the fluid is a little foamy.

Here what I have done,
I have changed the MVC pump previously as it was bad. It has chevron 1000 THF in it, 24-25 gallons. I have pulled the filter and it new now.

My question is,

Do the pumps have enough suction to pull air from the outside into the reservoir causing the pumps to suck air and foam the fluid? Is there any where else other than the filter housing where both systems are connected?

Thanks everyone

there is an Oring and a steel tube that leak air. the fix is to put in 5 gallons of trans fluid above full. If That fixes it cool If not it was cheap. Jim

So 24-25 gallons isn't enough? DO you guys put closer to 30 gallons in these?

As previously posted. Overfill above the tube. I added 5 gal to my 986

When it indicates full, put in another 5 gallons. Between various big frame IH there are differences. So give it a try. Jim

First thing we need to know is the capacity of the system so you know what five gallon overfull Is

I just added 5 gallons on my 986 which raised the level on the dipstick well above the full mark and then it worked without going home to see how much it held. Later someone told me there is a tube that is prone to leak and the remedy is to keep it overfilled rather than to do a proper repair. I think it is a common issue on those series.

(quoted from post at 10:44:16 08/05/19) So 24-25 gallons isn't enough? DO you guys put closer to 30 gallons in these?

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The amount in the owner's manual is enough IF everything is working fine.

Problem is everything is NOT working fine.

There is a suction tube that is supposed to be buried deep in the oil so it can't suck air. That tube is held in place by an o-ring which can sometimes fail or sometimes gets damaged when putting the tractor back together. This o-ring is above the normal level of the oil. That is where it is sucking air. Putting 5 extra gallons of oil in covers this area so it can no longer suck air.

There is no permanent fix other than to pull the tractor apart and replace the o-ring.

I have put 2000 to 3000 hours on a 1086 with the level 5 gallons above the full mark. Every once in a great while on a side hill it will still suck a little air.

Over filling will not hurt anything and maybe help to keep the oil cooler.

Lots easier to add 5 gallon oil,pto comes out lotta foul words etc etc. Did several when i worked at an ihc dealers

Don't overlook the filter cover as there are a whole lot of them that don't fit real good and some also get egg shaped after while. If you smear a good layer of grease all around the contact point of that round cover, it will suck the grease in any spot that is leaking. I have known guys to put a back up washer( rubber band) so to speak, in the groove so O ring protrudes more for a seal.

As for that o ring between the split, it should not affect rear pump until the front pump quits supplying oil entirely, then it could possibly draw air back wards through that passage because the o ring in question is well forward of the rear pump and front pump is still trying to pull oil forward.

I used to put a bead of 515 loctite around the outside of that o-ring in the split as insurance to prevent leakage. There really is not tube as it is merely a spacer that sits in a recess to keep o-ring from collapsing.

You have a seal pressed into the rear housing on the rear pump suction tube behind the filter that can cause you problems as well , even though it is below oil level , the oil is churning right close to that seal due to the gear driving the pump gear.

OK I'll try that, since that seems to be the consensus in everything you guys are saying. Is there a point where its overfull? Does that answer why the main pump is sucking air as well. Or is it the MVC pump sucking air and foaming the oil causing the mains issues? Does anyone know how much suction the pumps make, is it a lot or just a little?

one more question for you all. Where do you test the pressure on the MVC pump?

The 5 amount over hurts nothing, but covers the problem. We can't see in your tractor when it is running, so we can guess that when there is air in the system, it fails to work properly. Look at the GPM specifications for the two pumps and under stand that they can only suck at one atmosphere of pressure (atmospheric pressure pushes the oil in, nothing else does) and it is then pumped into a control system to move things at much higher pressure. Jim

Thanks Pete 23, You read the whole post and gave me some new ideas of the possible issue.

I pull the filter housing and added some sealant but with no effect. I then took the filer and screen out and it?s has seem to cure the issue. Since I?m new to this tractor I?m wondering if I was given the wrong filter for it.

Thanks everyone for all your help. I hope I got it now.

Out of curiosity, to an NON -IH person what is a MCV pump? Just a non-ackronym would help maybe.

Multiple Control Valve. It is a relay station like device controlling some of the tractors built in hydraulic flow and pressure.
It has its own pump (piggybacked on the primary pump) Jim