Ford 5000 PTO Revisited

[Mandomaniac]

Hey Folks,
Well, a good bit ago I was helped by a number of forum members with my 5000 PTO not completely disengaging. I popped the lid and replaced control valve (aftermarket AI brand...but still $$$), brake shoe, as well as found the cushioning spring disc in the PTO clutch was broken ....which I replaced as well.
Worked great after reassembly.....shaft completely came to a stop when lever disengaged, and smoothly turned when engaged.
Happy, happy, happy!
Operated correctly last hay season and did fine for first two fields this year. Then tractor seemed to bog down significantly when PTO turning round baler as bale grew. Managed to limp through baling the last of second field.....but noticed afterward the PTO shaft did not stop turning when lever disengaged. ARGGHHHHH!
Popped the lid today and found two of the internal spline friction discs in PTO clutch were warped. Ran into town, bought three new ones, replaced all 3 (external spline discs looked good), reassembled everything......BAD NEWS>>>
PTO shaft still turns (although slows somewhat) when lever disengaged.
What gives?????
Why would tractor bog down so much?
Why would friction discs warp?
One thing I can think of is clutch piston return spring might be weak? How can the clutch spring be checked?
Assuming the control valve I replaced is still good after only one year. The fact that it does seem to 'try' to disengage mean anything? Can valve be checked outside the tractor somehow? For that matter, any way to check it with lid popped? What would I need to do to run tractor with lid popped? Visions of fluid everywhere !!!
BTW, it does not act like brake is the issue (and brake was replaced last year). Can't stop it with levering wood against shaft.
Any thoughts on how to sort this out other than throwing expensive parts at it?
Popping the lid is not a terrible job...but a job none the less. Don't need to do it repeatedly! Sure would love to have some idea how to sort this out.
Any thoughts/advice would be appreciated. I need to hay!!!!!

 

[Bern]

Friction discs warp because they slip. They slip because the operating pressure is too low. You need to find out why your pressure is low before you keep throwing parts at it.

Tractor can be ran with the lid removed. You need to fashion a simple plate and hose assy to catch and redirect pump flow back to sump, and then you can run it. Run it with the oil level down a little so you can carefully inspect the PTO pressure line for leaks.

 

[Mandomaniac]

Hey Bern,
Thanks for the reply and getting me pointed in right direction.....
Will try to sort out pressure issue.

Oh....got to share this one.....apparently the mechanic elves slipped in the barn when I was eating dinner. Went out this evening to ponder tractor and wondered if maybe the new plates just needed to settle in.
You guessed it....the PTO came on with lever disengaged (not good), but seemed to almost quit when idled the tractor way down. Applied some resistance with a board and it quit! From that point, it would come in and out correctly. Stopping completely with no resistance when lever disengaged, quickly turning when engaged.
MAGIC!
Don't know if my theory on the discs is right or if something was blocking valve and cleared.......but hey, it WORKS AGAIN!

Still will try to evaluate pressures to PTO. Don't need to have it go bad again if that is the underlying cause. The 3 discs were $$$$. At least my labor is cheap...HAHAHAHA Sure would hate to be paying the dealer for that, too.

Any thoughts on why the tractor seemed to bog down so badly? Just old and worn out like me??????? Any diagnostic tips/plan?

Thanks again for the reply.

 

[Mandomaniac]

Still trying to wrap my poor old brain around what I was observing and what I found in the PTO clutch (warped friction discs) and the resulting failure to disengage corrrectly.

Tractor seemed to bog way down in RPMs and not move forward at same ground speed, but PTO kept turning round baler. Could put in clutch, stop forward movement, and it picked up RPMs.
This occurred at end of long HOT day running the round baler, although did not overheat.
No smoke, etc.....just acted like it was pulling a train. Even thought I had somehow engaged EBrake ...but nope.

So, chicken or the egg.......

....would this symptom's cause be DUE TO the PTO plates warping or would it CAUSE the warping? If it would CAUSE the warping, what would be the cause of the symptom????

Guess I need some ideas ...... :?

Bern?, souNdguy? Anyone????????

 

[Sean in PA]

(quoted from post at 08:13:42 07/24/13) Still trying to wrap my poor old brain around what I was observing and what I found in the PTO clutch (warped friction discs) and the resulting failure to disengage corrrectly.

Tractor seemed to bog way down in RPMs and not move forward at same ground speed, but PTO kept turning round baler. Could put in clutch, stop forward movement, and it picked up RPMs.
This occurred at end of long HOT day running the round baler, although did not overheat.
No smoke, etc.....just acted like it was pulling a train. Even thought I had somehow engaged EBrake ...but nope.

So, chicken or the egg.......

....would this symptom's cause be DUE TO the PTO plates warping or would it CAUSE the warping? If it would CAUSE the warping, what would be the cause of the symptom????

Guess I need some ideas ...... :?

Bern?, souNdguy? Anyone????????

I'm not totally familiar with the theory behind that independent PTO setup, but if the PTO was still turning the baler, but the forward motion of the tractor was slowing when the engine was bogging down I would suspect something in the transmission or somewhere else in the drive line rather than the PTO. If the engine was bogging down because of a drive line related issue, then I would think that would reduce the pressure in the PTO circuit which could cause the plates to slip and heat up and eventually warp. Again, these are just guesses on my part, but something to think about (or for someone else to shoot holes in).

 

[Mandomaniac]

Hey Sean,
Certainly seems plausible. Unfortunately, the service manual does not see fit to put any 'Troubleshooting' section in the 8 speed transmission or rear end chapters. This could be ugly.......
So, anyone out there with a basic troubleshooting plan for me.....PLEASE chime in! Thanks!

 

[Bern]

A few facts:

1) The transmission will not slip - period. Also, the 8-speed transmission is about as reliable and trouble free of most any trans out there, as long as you keep oil in it.
2) The transmission clutch COULD slip, but it's not likely to happen pulling a baler, and if it did, the engine would not bog down, it would increase in speed.
3) Warped PTO plates would be an issue ONLY when the PTO was OFF, only when it was necessary for them to be free of each other (frictions and steels). The amount of friction developed at this time would not be enough to be heard as a lug on the engine.
4) Because of the above statements, I will assume that the lug down of your engine was a result of a plug in your baler, not something wrong with the tractor.

I would continue on with the advice I gave earlier, that is, check the PTO pressures closely. Also, keep in mind that the original PTO brake on a 5000 (the pad style, not the brake band style) was marginal even in the best of circumstances. There are a lot of old 5000s running around with spinning PTO shafts.

 

[Mandomaniac]

Hey Bern,
Good points, and helps me in my thinking.

What I have come up with is perhaps another angle after 'researching' diesel engine bogging down under load.

Trying now to assure proper fuel delivery and air delivery.
Compression fading on this old beast might be possible, but no smoke and ran the baler fine for most of the time.

No apparent plugs in baler when it lugs down. Bale gets about 1/2 size and then engine RPMs drop and forward motion slows, yet PTO still turned baler rather than baler 'slipping'. Seems if PTO clutch was slipping, the bale would quit turning inside baler. Increasing fuel seemed to help only a bit....and then no effect. If clutch depressed, the RPMs picked way up.
This was after baling about 50 bales just fine....then occurred with each subsequent bale.

I will hook up pressure gauge according to service manual today and let you know.

Fuel and air filters not overdue, but will change/clean.
Might pull all injectors and clean them as well.

Any other thoughts/guidance definitely appreciated! Thanks again.

 

[Mandomaniac]

Well, I am pleased to report the pressure check recommended by Bern was within specs.
Ran just a hair under 150 PSI with PTO engaged. Manual says no less than 130 and no more than 165.

Found I was remiss in checking air cleaner properly. Oil bath was proper level, but the center inlet column was quite restricted with crud...especially just below the precleaner. Even the 'gills' of the precleaner were restricted.
Removed entire air filter system and cleaned everything out.

Hopefully this will turn out to be bogging down due to air flow restriction under load, leading to inadequate pressure on the PTO clutch causing disc warp, and resulting PTO failure to disengage.

If so.....a lesson learned. Complete air cleaner maintenance, not just checking bath, is required!
If not the answer......still open to any thoughts out there!

 

[Bern]

I forgot to tell you to make sure you check the pressure with the oil hot. You might get good readings with cold oil, and not so good with hot oil. Leave pressure gauge hooked up and check it often throughout the day.

A plugged air cleaner does not make sense with an engine bogging down after several hours of work. Sorry to burst your bubble there. Air cleaners don't just all of a sudden "plug up", rather it is very gradual. I still have no other thoughts on that. I'd have to see/hear it for myself to have a better idea on that.

If you know someone with a PTO dyno, that would be the ticket.