4100 starting and PTO problems

Chris2 · May 10, 2004

I just bought a 1968 ford 4100 3 cyl diesel it runs excellent but I have found two problems with it, one is once it reaches operating temp it is hard to start, leave it alone for about 5-10 min and it will start but still has to be spun over several times. It starts with a bump of the key when it is cold even after sitting for over a week.
The other problem is the PTO shaft never stops spinning, with it idling in neutral and the PTO disengaged I can almost stop the shaft with my hand but not quite so I have to turn off the engine to hook up the bush hog. Even with the bush hog hooked up it still has enough power to turn the blades slowly but fast enough to cut light grass witch could be very dangerous.
Thanks for any help.

jinman · May 10, 2004

Do you know if the previous owner used the PTO much? If not, it may loosen up with use. Also, how are your fluid levels in the transmission? Do you have a dual stage clutch type PTO or is it independent? All these things have a bearing on PTO operation. I'll check to see if I have any documentation, but I think mine ends about 1965-66.

Sorry, I don't have any idea about the starting issue. Does your tractor smoke? The only thing I can think of is lower compression when the engine heats up. Maybe someone else has a better idea.

Chris2 · May 10, 2004

I really don’t know how often the tractor was used I will ask the previous owner about it. I don’t know if it is a dual stage clutch, this is my first tractor and don’t know much about it how do I tell.
The engine doesn’t smoke at all it seems to be in good shape it holds 70 pounds of oil psi.

rambler · May 11, 2004

I do not know about the starting issue.

Do you need to push the foot clutch in to shift the pto in & out of gear, or does it have it's own independent lever & only have to move that in or out of gear without needing the foot clutch at all?

If you have independent, Ford typically uses a hydraulic system that uses a very low hyd pressure to clamp the pto brake. The spinning you mention is very common, and means one of several things. Your hyd pump is getting worn. The pto brake deal has some leak to it. Your hyd system has a leak somewhere & it shows up first here because the pto brake only takes 600# or so of pressure. Something is out of adjustment.

This is pretty typical of that type of pto, so I'll bet it's what you have. Put the engine speed up to about rated pto speed or more, see what happens. Often times this will create enough pressure to lock the pto brake. While at idle, the pto will spin.

If you have a 2-stage pto clutch & not the hyd live, it's possible you have too thick an oil in the rear end, or that the clutch is about used up or out of adjustment.

--->Paul

Chris2 · May 11, 2004

I do not have to press the clutch to engage the PTO. I tried running the tractor faster but it didn’t help. It doesn’t appear that it got regular oil changes, could the oil be old or the wrong type? I plane on changing it next week. I will find a place to install a psi gauge and find out what kind of psi it is putting out. I leave for work tonight and won’t be back for a week so I will do that next week. Does anybody know wear a gauge can be installed?
Thanks.

RickB · May 11, 2004

By your description, your 4100 has independent PTO. The PTO brake is a small lined pawl, and is most likely worn out. The brake is applied by coil spring pressure, and released by the same hydraulic pressure from the same valve porting that supplies lock-up pressure to the clutch itself. Chances are very remote that you have a pressure or flow problem if the PTO drives positively when engaged. The fix is to split the tractor between the transmission and rear axle center section, remove the PTO clutch and its support and replace the brake pawl. Check the clutch discs and plates, and replace the clutch sealing rings and piston seals while it is apart. The starting problem could be electrical, relating to cranking speed, or an injection pump/timing issue.

Chris2 · May 11, 2004

Sounds like a lot of work but I do have the tools to do it. Would it hurt to leave it alone for a while? I’ve got a year or two of FEL and box blade work to do on my new land before I’ll be ready for a bush hog.
Thanks.