806 MCV/Pump issues

I'll say right off that I haven't the means to check the flow, maybe the pressure. Anyhoo, I have this 806, power steering is kind of weak. Noticed the other day that if I was holding the brakes and I turned the wheel, the pedals would drop. Quit steering and the pedals would spring back. Brakes never slipped and I was backing up a hill. Also noticed the TA shifting from lo to high on its own a couple of times when moving from a dead stop--not constantly, though. Everything does work as advertised. The TA will shift crisply both ways in all gears, steering is tight, and the brakes easily lock up the wheels. Filter is new, and the fluid is clean and all the way up. Given the weak steering, I think I need a new MCV pump. What do you guys think?

One thing I need to do is check the oil tellight. It does light before starting the engine, but not when I push the clutch.

Chris B.

Since i am not there to do the checking for you lets start with the easy Stuff first . Start off Adjusting the clutch the transmissiion brake and then the dump valve along with getting the telltale light working before you start the adjust ments Once you have the teltale working then adjust the clutch free travel to one inch from the ft edges of the plat form to the back side of the pedal . Next go to the right side of the tractor and the clutch brake linkage is there First break loose the lock nut on the rod , next remove the pin now you need some one to play dumb and set in the seat and psh the clutch pedal down to the stop on the side of the clutch pedal against the deck plate Now pull the transmission brake arm forward as far as it will go and adjust the clevis till the pin will slide in freely , Next let the clutch pedal up and add one to one and a half turns more to the clevis , now here this depends on the amount of ware on everything and this will be good enough for now . put the pin back in and the hair pin and lock the lock nut down snug . next 7you start the tractor and with the tramsmission in Nutrel and the park loc ENGAUGED and engine ideling go back around to the left side and now we are going to adjust the dump valve , first break loose the lock nut a 7/16th wrench is needed for this now back off the dump valve bolt about 4-5 complet turns . There should be not teltale light on at this time , now push the clutch pedal down to the stop and HOLD it there and start to turn the dump valve bolt in this will take that person again that you had the first round for this have them watch for the teltale lite to come on as soon as that lite comes on STOP turning the adjusting bolt let the clutch pedal up and THEN ADD ONE MORE COMPLETE TURN TO THAT BOLT and set the lock nut . Now we know that it is adjusted real close if that dump valve is out of adjustment that will give you the double shifting . Now if this does not help with that then you may have low pump out put and thenm again it maybe a problem inside the MCV as to weak springs on the spool valves or you may have some scoreing on the spools and they maybe sticking . I realize that you do not have all the toys that i have to play with so here you will have to find a fitting that will go into the Bottom right of the MCV and a gauge that can handle 600 lbs pressure . You should have no less then about 200 lbs on the gauge myself on a 806 i like to see them at 220-235 if it is stock if it has been tweeked then 245-260 . Hey it's just my way . Given the age of these tractors the springs in the MCV are getting weak . now here you will need atleast a I T manual for spring lenght and spring pressure and before you tear into the MCV first set down and read the chapter till you have it in you head . IF you do remove the MCv then you will need a clean place to work and one of the wife cookie sheets ( she will love for this and oh BTW don't make cookies on it after Hy Tran chocolate chippHy Tran flavored cookies don't go well ) . Plus you MUST ues the same thickness gasket to re mount the MCV . So you will need a dial caliper for checking the thickness of the gskt and also the spring free lenghts and USE NO RAGS to wipe any parts Compressed air and clean parts cleaning solvent of your choise . . IF you feel the need to replace the pump then now is the time . After all this and you still have aproblem then well dig into it at a later date .

Thanks for the fascinating response. I guess I get to dive into this MCV body soon. I've one off a 966 apart and didn't mess that up, so I should be able to handle this. I'll figure out how to plump a gauge into the port to check the pressure and go from there.

Thanks, Chris B.