MCV on 826

Tim Mahony · Feb 20, 2010

On a cool morning my tractor will not have power steering or decent brakes and the TA will not change. It feels like the pump is not pumping.Generally, if I leave it at fast idle and engage the hydraulic levers it will all come good after 10 to 20 minutes. I have recently found by removing the plug for the Control valve Oriface and turning the motor over for a bit until oil comes out, then replacing the plug it will work fine.I feel the pump is ok as everything performs well once it starts working.Is an airlock a likely problem? How hard is it to remove the control valve oriface? I tried doing what the book suggests and had no luck. Could it be missing? I performed a pressure test when steering was working and it met all the specs.Any suggestions???

darin in sk · Feb 20, 2010

I have the same problem on an 806. It was our neighbors and when it started acting up, I replaced the pump a couple times, just had used ones from our salvage yard, I even changed the mcv. it'll work great for a few times then the next it'll act up. I just remove the 5/8 head plug on the back side of the valve and use a hand suction pump to get the oil up there, then it's good for a while. Been stumping me for a few years now. Good to know that i'm not the only one with this issue. Hope someone out there has a solution!

the tractor vet · Feb 20, 2010

well it could be sucking air between the speed transmission and the range transmission , it could be leaking back at the suction tube in the rear housing . It could be this and that . Then it might be that the pump is just getting old and tired. alsong with the springs and seals in the MCV. Now to know if the pump is doing what it should do then it needs to be flow rated , and that is something that only a shop with a flow rater can do . Now assuming that the Hyd, oil is nice and clean and free of any water and that the filter is also clean then do this add three to five gallons of hy tran and see what hap[pens . Being over full will not hurt a thing and will take away any problems with the air sucking . If everything works like it should then fine run it till ya got to split it and when you do the split between the range and the speed trans then it will get a new O/Ring and gskt there and that takes that part of the problem away and then that leave the pick up tube .

Tim Mahony · Feb 22, 2010

I think the "Tractor Vet" could be on the money.I will do as he suggests and see what happens.I have changed the tranny oil and filter recently and no change. The book suggested that the oil could be too thick so I changed to Caltex Textran TDH premium and it seemed to improve it a bit but it is still a pain if things don't respond straight away.Could be needing to do a split to replace the clutch shortly anyway so will change the gaskets and 'o'ring. Thanks for your effort.

Tim Mahony · Feb 27, 2010

Have overfilled the tranny and tried the tractor on 3 occasions and it steers right away so I am looking at a tractor split in the near future to replace the 'O' ring and gaskets and check the pick-up tube. Many thanks to the "tractor vet" for his suggestions.

MCV on 826

Tim Mahony

New User

darin in sk

Member

the tractor vet

Well-known Member

Tim Mahony

New User

Tim Mahony

New User

Similar threads