PYO Clutch

[FotonOwner]

Hi,
I find that the PTO clutch on my Foton FT254 does not seem to allow the drive to be engaged when the engine is running. There is no description of how the clutch or drive works or how to adjust it.

The linkage (RHS) appears to move the clutch shaft about 10 - 20 degrees only but if the linkage is disconnected then the shaft can be rotated by hand with little resistance through 360 degrees or more.
I would expect there to be something like a lever attached to the shaft, inside the gearbox, that operates the PTO clutch.
Does anyone know how this clutch works? Should there be a lever or is there some other type of mechanism that allows 360 degrees of rotation?
I think I should be able to remove the plate on top of the gearbox by removing the 6 hold down bolts and perhaps the two bolts on the clutch shaft, as well as the gear XF lever. Then I could look in at the mechanism. Is there any danger in doing this that I may disturb something?

 

[Bob Rooks]

It appears to me that you are only six bolts away from the truth.

 

[bluechip]

Teh PTO clutch is controlled by the same pedal as the main clutch. If you have a 2 stage clutch, the first 70 percent of so of pedal travel will disengage the main clutch and the remaining travel disengages teh PTO clutch. the linkage you are showing is a devise foton uses that appears to release tension on the detent balls on teh shift rails when you step on the clutch. I believe this is inteneded to make it impossible to shift without stepping on the clutch. I only had 2 FT254 and it was about 7 years ago, I remember seeing this linkage but never lifted the cover. the fact that it will turn 360 degrees would indicate to me that it is a cam abouve the springs that hold the detent balls. do you notice any difference in shift effort whith clutch pedal depressed or not?

 

[FotonOwner]

Teh PTO clutch is controlled by the same pedal as the main clutch. If you have a 2 stage clutch, the first 70 percent of so of pedal travel will disengage the main clutch and the remaining travel disengages teh PTO clutch. the linkage you are showing is a devise foton uses that appears to release tension on the detent balls on teh shift rails when you step on the clutch. I believe this is inteneded to make it impossible to shift without stepping on the clutch. I only had 2 FT254 and it was about 7 years ago, I remember seeing this linkage but never lifted the cover. the fact that it will turn 360 degrees would indicate to me that it is a cam abouve the springs that hold the detent balls. do you notice any difference in shift effort whith clutch pedal depressed or not?

Bluechip
Thank you for the response, that is helpful.
You would not be able to feel any change in tension due to the shaft when pressing the clutch pedal. There is just a slight change in tension in your fingers as you rotate the shaft arm with the linkage from the pedal removed, it feels something like as if the shaft were slightly bent.
If it is meant to put tension on the pedal then it is totally ineffective and seems to be a strange way to do it.
Do you know of any handbook that shows an exploded view of the assembly?
Looks like I will have to pull it apart and look in.

 

[FotonOwner]

Teh PTO clutch is controlled by the same pedal as the main clutch. If you have a 2 stage clutch, the first 70 percent of so of pedal travel will disengage the main clutch and the remaining travel disengages teh PTO clutch. the linkage you are showing is a devise foton uses that appears to release tension on the detent balls on teh shift rails when you step on the clutch. I believe this is inteneded to make it impossible to shift without stepping on the clutch. I only had 2 FT254 and it was about 7 years ago, I remember seeing this linkage but never lifted the cover. the fact that it will turn 360 degrees would indicate to me that it is a cam abouve the springs that hold the detent balls. do you notice any difference in shift effort whith clutch pedal depressed or not?

Bluechip,

I took the thing apart and it is exactly like you said.

It just seems incredible that they would go to so much trouble to manufacture this complicated detent thing that seems to have no possibility of working.
The spring tension on the pedal far exceeds anything the detent could apply.
In this case I find that the pins are too short to contact the shaft for about 90 degrees of arc which corresponds to the operating range. There doesn't seem to be any way of adjusting it so it would fall within the range without cutting off the lever and welding it on 45 degrees around.

I may as well remove the whole thing as it can't ever work.

My problem now is why isn't the PTO clutch operating?
Under "General Technical Specification" it says "Clutch Single plate, spiral spring press type, normal connection, single function"

I thought I read (perhaps on the web) that it was a dual stage clutch, as you described, but it doesn't say that in the book. Also under Engine - "Clutch Single plate, dry ...., not single dual stage" what ever that means.

Even if it is a single clutch, it should enable me to engage the PTO when the engine is running, without graunching he gears.

What do you think?

 

[greg_g]

I don't see the steel balls. In the case of one ball per pin, it adds about 8mm in travel length. If there are two - one either side of the pin - double that. A ball-detente system won't work without'em. In some cases, the pins and springs wear out. The ends of the pins should be flat. Rounding off means wear has shortened them. Compare all your spring lengths too. One or more of them may have become weak, and/or broken, and/or compressed. Anything that shortens pin travel can lead to the point of defeating the system.

//greg//

 

[bluechip]

My point is that the device you removed has nothing to do with the PTO. It is attached to the clutch pedal. the clutch removes tension from the springs makeing the MAIN gear shift easier to shift. Well, actually makes it hard (impossible?) to move the gearshift lever without stepping on t he clutch, also helps the tractor from popping out of gear. but again it has nothting at all to do with the PTO.

Assuming you have a 2 stage clutch, if the adjustments are not correct, you may not have enough pedal travel to release the second stage, in which case, the main clutch will stop the tractor but the PTO clutch will not release and attempting to engage the PTO will grind the gears. Try putting the PTO in gear with the engine off, then start the engine and see if the PTO stops when you push the cluth pedal all the way down as far as it will go. if it does not stop, it is not disengaging correctly.

 

[attaboy]

Hi,
I find that the PTO clutch on my Foton FT254 does not seem to allow the drive to be engaged when the engine is running. There is no description of how the clutch or drive works or how to adjust it.

The linkage (RHS) appears to move the clutch shaft about 10 - 20 degrees only but if the linkage is disconnected then the shaft can be rotated by hand with little resistance through 360 degrees or more.
I would expect there to be something like a lever attached to the shaft, inside the gearbox, that operates the PTO clutch.
Does anyone know how this clutch works? Should there be a lever or is there some other type of mechanism that allows 360 degrees of rotation?
I think I should be able to remove the plate on top of the gearbox by removing the 6 hold down bolts and perhaps the two bolts on the clutch shaft, as well as the gear XF lever. Then I could look in at the mechanism. Is there any danger in doing this that I may disturb something?

I have a 354 .. same principle .. it is a two stage clutch. If you have excessive moisture, and no clutch disengagement over months .. the plates may well bond together. Most vehicles are expected to be operated 500 hours year .. and tractors comercially .. 2,000 hours a year.

My Jinma ... was suppossesd to have a "winter link" ... to keep the clutch depressed .. during winter, or prolonged non-use events. I am retired .. anything over 200 hours a year on any tractor, is work. The "winter-link" to keep the double clutch disengaged .. dosen't exist. Like "parking brake" on a Jinma .. getta piece of wood.

and ... one other thing about Jinma pto's .. your handle may well be backwards as to PTO speed.

And ... unlike kubotas .. fords ... there IS one lever, that totally engages and dis-engages .. ALL pto drive. You found that yet?

 

[FotonOwner]

My point is that the device you removed has nothing to do with the PTO. It is attached to the clutch pedal. the clutch removes tension from the springs makeing the MAIN gear shift easier to shift. Well, actually makes it hard (impossible?) to move the gearshift lever without stepping on t he clutch, also helps the tractor from popping out of gear. but again it has nothting at all to do with the PTO.

Assuming you have a 2 stage clutch, if the adjustments are not correct, you may not have enough pedal travel to release the second stage, in which case, the main clutch will stop the tractor but the PTO clutch will not release and attempting to engage the PTO will grind the gears. Try putting the PTO in gear with the engine off, then start the engine and see if the PTO stops when you push the cluth pedal all the way down as far as it will go. if it does not stop, it is not disengaging correctly.

Bluechip,

Yes I understood your point that it had nothing to do with the clutch. There were no balls in the mechanism and most likely that is why it doesn't do anything. I can certainly get the PTO working by starting it engaged but haven't tried declutching yet. I am reasonably sure that the pedal hits the stop without any disengagement.

 

[FotonOwner]

I have a 354 .. same principle .. it is a two stage clutch. If you have excessive moisture, and no clutch disengagement over months .. the plates may well bond together. Most vehicles are expected to be operated 500 hours year .. and tractors comercially .. 2,000 hours a year.

My Jinma ... was suppossesd to have a "winter link" ... to keep the clutch depressed .. during winter, or prolonged non-use events. I am retired .. anything over 200 hours a year on any tractor, is work. The "winter-link" to keep the double clutch disengaged .. dosen't exist. Like "parking brake" on a Jinma .. getta piece of wood.

and ... one other thing about Jinma pto's .. your handle may well be backwards as to PTO speed.

And ... unlike kubotas .. fords ... there IS one lever, that totally engages and dis-engages .. ALL pto drive. You found that yet?

attaboy
Yes, I am also retired and don't do too many hours at all. I have no idea how to locate the PTO clutch or spring it open. I have plenty of wood but what to do with it?
I do recall having that problem on the main clutch of my Nuffield and someone tapped it with a bar through a hole in the housing.
The 540 position is rearmost, if that is backwards.
Yes the engagement lever is on the RHS and I only recently found out I should have it disengaged when not in use.