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My 886 dont want to raise the loader if the engine is not running at least 1200 rpms.  Checked the pressure and its weak. Steering and breaks works good.  Gone to replace the pump. Am i correct, its the back pump and not the one behind the multicontrol valve?  70932C91 should be the correct # if im right.

 

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If RPM's make a differnce in raising or not (not just how fast) than likely it is the pump, or a fluid leak.  Yes, the back pump.  I recommend putting in the extra teflon ring on the pressure passage on the plate.

We had a 1486 where the port on the plate did not line up with the rear housing port.  The Oring would promptly deform and let high pressure oil dump out back into the tranny.   It acted a lot like you mention...poor pressure & flow, esp at low RPM's.  The Teflon ring did no good, of course, because the ports didn't align.   Took me 3 pumps to figure out what the problem was, and a day of welding/grinding to move the port over in the rear casing.   Fixed the problem.

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Thanks, I traded for this tractor a couple of months ago, straight 1979 model with only 5000 hrs.  Im the 3rd owner.  I know the pressure is low as it will pick up loader if rpms go up.  I also know i got to put a kit in the hitch cause it falls when tractor is shut off, im sure the orings need replacing.  I done all this on my 1086 had years ago .

 

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  • 1 month later...

Im still having problems with hydraulic problems. Tractor is 1979 model(open center). Replaced pump and worked great for short period of time.  Then i lost pressure even worse than before i changed pump.  I changed the relief valve with the one off another tractor, didnt help.  I have checked the unloading valve which i did find part of an oring that didnt belong.  I went back and checked the pump to make sure it hadnt sheared the key and also orings there.  I hope to have a gauge monday to check the pressure where it comes out of pump on housing.  I dont have enough pressure to raise the loader unless engine is at least 1500 rpms.   The guage i got dont show any pressure at the remotes when running idle and the engine dont load up when the cylinders bottom out with high rpms. Have I missed something before i pull hitch?  With the top link plate off, I can see oil churning in the front where the pump is located, but nowhere else unless you raise the 3 point and lower it.  3 point dont have much pressure either, i put a loader bucket of a smaller tractor on arms and it wouldnt raise like it should either with the weight.  Thanks 

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Is your tube going to the pump pushed in to the pump all the way? I had this problem with our 786. I replaced the pump, and totally forgot about the crossover tube going in the hydro pump from filter. Wasnt that big of a job, and it would do like you described.

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Hard to think where it is unless it's in the valve body somewhere. Could be a blown oring in there, but usually they leak to the outside. Could possibly be in the remote outlets. Are the hoses going to the rear metal or have been replaced with rubber?

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All 4 are metal.  When you look in from the back while its running, only oil moving is at at  the front where the pump is located and where the axle cones out the left side, above the pump. I have had the relief and the block it goes in all aprart and didnt find anything i thought might be the problem.

 

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Hmmm... Sounds strange to me. The filter is new and clean with new o ring for filter cover? The seal to the pump cross over is good? All fits snug? Seal on pump cover is good? If so to all of this, there should be no reason why there isn't oil at the valves. Try loosening a line at the outlet and see if oil comes out there. If so, then either there is a leak internally or there is a blockage at the remote hook ups. I've seen the little "fingers" ( for lack of their proper name) are worn bad enough they do not open the hose fittings well, but usually allow some flow through. 

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New pump fixed problem. I would start by disassembling new pump to see what happened to it.

Other questions.

When observing through rear cover was auxillary lever actuated?

Has filter been inspected since second failure?

Is loader operated by auxillary valves?

If no. Where is oil sourced and returned?

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I have took the remote valves apart, found nothing. With the plate off the back for the center link, only oil is moving is at the front where the gear turns the pump. Also noticed a little oil coming out the bearing on the left side where the short axle comes out of the brake housing.  It really dont change with the levers moved.  I changed the filter again friday.  Didnt cut it open, but it looked Ok, but I had an extra one at shop.  The loader plugs in the remotes at the back.  I hadnt had a chance to get back to it so far this week.  Be at the shop tomorrow. I have done a little checking on my 1256 to compare pressures and when i go back to shop. I have about decided, its either pump or i got something stuck internal. I got a pressure gauge to put on housing where pump fastens, to see what kind of pressure i got there. It should be close to the same as my 1256.

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Its not, theres a little coming out from the left short axle, but none on the right.  On my 1256, theres oil coming from the sides and top, which I know its seen its better days, but it works.

 

 

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OK went to bed but I'm back. My old brain don't work like it used to. Got hung up on no return oil. I think in later tractors it was redirected. I just don't have details in my head any more. With no oil coming down in rear frame. It is simply telling us the problem is not there. Which leaves us with the pump, its mounting and the cast in passage in rear frame. The conversion question is still relevant. With that I bid you good morning. I'm going back to bed.

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Snoshe,  you are correct about the shaft.  This is a 70 model with open center hydualics.  I dont believe anything has been changed.  Its just got 5000 hrs on a working tach and Im the 3rd owner.  Hoping to have some answers this evening as Ill be in shop today.  JaredT,  you are correct, lots of stuff thats no account be put on and having to be replaced again.

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2 hours ago, bmk said:

This is a 70 model with open center hydualics.

You have said like 3 times this is a 1979.  It isn't a car.  The year made is grossly irrelevant.  We only need to know if it is an open or closed center.  Which year could reveal, but not necessarily because so many were converted back to open center.  

 

Anyway.  You ever put a pressure gauge in the remote outlets on back?  You really aren't telling us jack without pressure readings.  I don't care what it is making at the pump honestly, I want to know what is getting to the remotes.  If there is a problem, checking at the pump is useless anyway.  Pump can't make pressure if the pilot relief and unloading valve are not functioning properly.  Get us some hard numbers please. 

 

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It's only going to get worse as time goes on. I'm sure someone took a worn out pump to a job shop and said, "Make a bunch of these." So, they made it. Right down to the groove worn in the shaft from the seal running on it for 40 years.

IH isn't making these parts anymore. The original tooling is gone. The specs are gone. The knowledge of how they were made is gone. What you are left with is a machine shop's best guess at what a new pump should be, tempered by the need to keep costs down as they underbid the job and won't make any profit if they put too many man hours into figuring it out.

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Thats a big problem for you guys turning wrenches for a living.  All the guys locally says it getting where at least half the parts they get either dont fit or wont work like they suppose to.      On my new  pump, the seal on the back plate was about half out of the groove, letting it loose pressure.  

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