674 questions (PTO, Brakes, and Range)

I recently acquired a 674, and it has 3 main problems.

The PTO is always engaged. With the tractor off, I can turn the shafts somewhat less than a full turn. With the tractor running, the PTO is engaged. I can move the lever and hear a different sound with it "engaged" (presumably hyd oil being sent to the clutch pack). I did have to use some penetrating oil and muscle to get the spool to actually move in the MCV. It appears as if it is out of adjustment in that I cannot pull the lever all the way back to the disengaged position at this point. It just won't go. Is this a linkage issue? funkiness in the valve? Welded clutches? What are you thinking?

High range works, but the tractor occassionally jumps out of, well, it (HI). Low and reverse work as they should. All gears behave similarly. It is just hi. The previous owner removed the linkage because it was jumping out, and I have yet to see it. I used hi by moving the arm by hand and moving the range lever to where hi would be to avoid collisions in the trans. There are no strange noises. It just stops moving as if you shifted out of hi. Is this a gear issue or a linkage adjustment issue?

Brakes are less than useful. The right brake works sometimes. With them linked you can pump a bit and get a pedal, but there isn't much stopping. Is there anything I should/can check before I go into it for the brakes?

btw, it runs great, looks good, has great rubber, and was pretty darn cheap.

Thanks in advance.

Hi, Re PTO, you are on the right track, usually the linkage is siezed up or spool valve in MCV is stuck. There are adjustments fot the PTO lever and for the hydraulic pressure settings for PTO clutch.
Re jumping out of HI range, never had that problem and my brother has a 1972 454 same tractor but 3 cyl engine with over 15,000 hrs and sloppy gear shifters and it never jumps out of gear. Possible adjustments again.
Re brakes, the hydraulic brakes are the weak point of this model of tractors. First check for hydraulic leaks by the bottom of dash, under the battery box and from under the top of transmission cover in front of seat. In any case the brakes will have to be bled and for bleedind procedure just serach archives on "JimB2" and you will find procedure.

Great utility tractor, especially the Diesel model.

Good luck
JimB

So what valves misbehaving can lead to the PTO being on all the time? If the PTO is staying on (and the MCV plate gasket is known to be good), what must be open and allowing pressure to get to the PTO port? I can disconnect the linkage completely and the PTO stays engaged. I have removed the pto valve from the MCV, and I did not notice any problems. I'm not saying there isn't a problem, but the valve moved freely. I am contemplating hooking a gauge up to see exactly what kind of pressure I have while it is "off" and still turning. As I said before, you can hear something different going on when the PTO is officially engaged--this would lead me to believe that the pto valve is opening more (and it is not a straight and full flow leak), but can a leak on that valve in the closed position cause this? Are there any remedies for a valve that leaks--I only see two o-rings in the breakdown, and I doubt either are in "keep the pto from turning" places.

BTW, I'd assume a stuck flow divider valve would keep something from working--not keep something from turning off.

Thoughts? And thanks again.