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.

 

[FotonOwner]

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//

Thanks greg,
Steel balls missing most likely problem.

 

[FotonOwner]

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//

Greg,
Yes that makes sense lack of steel balls will allow the free-play I am seeing. The thing is that it is basically new (very little use) so the balls must have been missing since it left the factory and little likelihood of any wear on the springs or pins.

 

[greg_g]

Greg,
Yes that makes sense lack of steel balls will allow the free-play I am seeing. The thing is that it is basically new (very little use) so the balls must have been missing since it left the factory and little likelihood of any wear on the springs or pins.

Well, let's just hope they're not at the bottom of the gear housing. When my KM454 was almost brand new, it developed a problem with one of the shuttle shift rails - also a pin/spring/ball/detente arrangement. I knew the field fix, and had the cover open and pin/spring/ball removed. Some observer who thought he knew more about it than I managed to drop the ball into the housing. I fished like crazy with a magnet, but never did find the dang thing. Replaced it, reassembled the shifter mechanism, and abandoned the search for the missing ball.

This was in the fall of the year, and from that point on the gear oil stayed pretty thick in the cool/cold weather. The following summer though, I was bush-hogging on a hot July day - and heard a loud bang from down by my feet. Long story short, the gear oil got thin enough to where that steel ball finally worked it's way up between a couple large meshing gears. That missing 5 cent steel ball ended up costing me several hundred dollars in gears/shafts/bearings/seals and labor.

So I strongly recommend that you don't waste any time getting a parts manual for that tractor. Open it quickly to the section with that lever mechanism. Look specifically for whether or not there actually ARE steel balls associated with the linkage. If no, you're ok. If yes, I'd strongly recommend finding out where they went.

//greg//

 

[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.

Thanks bluechip,

I tried starting it engaged and found the PTO will not stop turning with the pedal fully depressed. Even if it was a single-stage clutch it should have stopped, so must be a dual-stage.
I took some photos to show the pedal depression. Released there is about 60-70 mm clearance from the stop. There is about 20-30 mm of free play where nothing happens then 20 - 30 mm where the clutch operates then 10 - 15 mm between the lever and the casing with the pedal fully depressed. I can't get the pedal to go down further even with considerable force.

I thought the detent mechanism may be limiting travel so adjusted it so it doesn't prevent the pedal moving forward and can't get the remaining 15 mm. Would there be any value in reducing some of the free-play to try to get the clutch to take up sooner? It is hard to see the remaining 15 mm doing the trick even if I could get the lever into that position.

Any ideas?

 

[FotonOwner]

Well, let's just hope they're not at the bottom of the gear housing. When my KM454 was almost brand new, it developed a problem with one of the shuttle shift rails - also a pin/spring/ball/detente arrangement. I knew the field fix, and had the cover open and pin/spring/ball removed. Some observer who thought he knew more about it than I managed to drop the ball into the housing. I fished like crazy with a magnet, but never did find the dang thing. Replaced it, reassembled the shifter mechanism, and abandoned the search for the missing ball.

This was in the fall of the year, and from that point on the gear oil stayed pretty thick in the cool/cold weather. The following summer though, I was bush-hogging on a hot July day - and heard a loud bang from down by my feet. Long story short, the gear oil got thin enough to where that steel ball finally worked it's way up between a couple large meshing gears. That missing 5 cent steel ball ended up costing me several hundred dollars in gears/shafts/bearings/seals and labor.

So I strongly recommend that you don't waste any time getting a parts manual for that tractor. Open it quickly to the section with that lever mechanism. Look specifically for whether or not there actually ARE steel balls associated with the linkage. If no, you're ok. If yes, I'd strongly recommend finding out where they went.

//greg//

Thanks greg,
I couldn't get the top plate off the gearbox and saw no sign of the balls. So I am sure I didn't drop any. I am convinced that it should have something like that, as the flat section of the shaft could only operate on something like a ball. The pins are far too short and would be too difficult to get to slide.
I am inclined to think that the balls were never there rather than being dropped inside and I have been operating through some hot weather already.

 

[greg_g]

Well, I can't really see those on my tractors, but I know they're there. Being only 8mm (diameter), it's hard to fish them outa their respective holes. I use a small magnet on a wire to get them out. Once they're stuck to the magnet, the risk of dropping them into the sump goes way down.

//greg//

 

[FotonOwner]

Well, I can't really see those on my tractors, but I know they're there. Being only 8mm (diameter), it's hard to fish them outa their respective holes. I use a small magnet on a wire to get them out. Once they're stuck to the magnet, the risk of dropping them into the sump goes way down.

//greg//

Greg,
Is your machine much the same as the Foton? My is Europrd branded but seems to be the same, or a copy of Euroleopard. I see on the web that Euroleopard is also a Foton brand.
I assume that the balls will be on top of the pins so only the spring and pins are down the holes. I also assume that the holes don't go into the gearbox but are just in a blind hole in to top plate. In which case they can't get into the oil. Haven't tried putting anything down the holes to check.

After I posted the photos of the clutch travel I realised there was something in the book about adjustment and found that the 20-30 mm of free travel is exactly correct, but there should be a stop to limit the engaged travel to 17 mm. I dug out some bolts and got one to fit so it now limits the travel to about 17 mm. Have no idea what harm could be done by pushing the clutch pedal in too far.
There have been so many bits and pieces missing or broken on this machine and it is basically new, never been used before I got it. I can be sure of that because the clutch pedal was mounted upside down and had to be cut off with oxy torch and re-welded on the right way up.
Also the hollow hydraulic filter bolt was too long and tightened up until it cracked the top plate disabling the hydraulics.

Maybe one day it will work properly.

 

[greg_g]

Foton products and Kama/TaiShanproducts are similar, but not identical. The ball-detent concept however, is fairly universal. It's usually detent-->ball-->spring-->pin. That's for sliding rails anyway. Without a parts manual, I can't speak specifically to your device - especially since you're calling them "blind holes".

I strongly suggest you expend all efforts to put together a full set of user manuals (usually 4) for that tractor. Despite numerous complaints about the "Chinglish", I'd consider it money well spent. The exploded diagrams in the parts manuals really help first time owners understand how these things are put together.

I don't understand (1) how a clutch pedal could be installed upside down, or (2) why it had to be cut off with a torch. That could be part of your clutch travel problem right there !!

If you're talking about external filtration, I doubt the hydraulic filter bolt was too long. More likely there was a bad seal. I have a similar issue with my KM454, which requires a very precise alignment before tightening down the cannister bolt. Otherwise - the seal is compromised.

Chip must be out of town, so I'm going to take the liberty of addressing your response to him. Just like a manual tranny in a truck or car, a one stage tractor clutch has no PTO function. Its only job is to engage and disengage the transmission. This type is called a "transmission PTO". On this type, the PTO is basically engaged full time. A two stage clutch does both; transmission and PTO. With this type you can engage/disengage the PTO with the clutch pedal. It's called a "live PTO". There's a 3rd type - the "independent PTO" - but I don't know of any Chinese tractors that employ one. CLICK HERE. But adjusting pedal travel at this point amounts to putting the cart in front of the horse. Before doing that, the throwout bearing must be verified as correctly positioned relative to the clutch release fingers. Since it's typically about 2mm, that could MORE than account for that 15mm you can't account for. Have you even opened up the clutch inspection window to see what's going on inside?

//greg//

 

[SensibleNick]

Sorry.. I haven't checked the chinese tractors area recently...

I have an FT254 + parts/maintainance Manual at home, but I can see that your shift-pattern is very different from mine, and that you most likely have the single stage clutch.

There is a possibility that my manuals cover your gearbox though,. I'll have a look when I get home (3 hours from current time or so) and post any pictures that might be useful.

 

[bluechip]

2 stage or single, stepping on the clutch shoud stop the pto. sometimes they will keep turning if they don't have any load on them as there is not a brake. conentric shafts, the pto disk slightly touching the flywheel, etc. With an implement attached, the pto should not start turning until you let up on the clutch pedal, and you should not get grinding if you put pto in neutral, start the tractor with foot on the clutch, engage pto, then release clutch. If tractor has set for long time, could be PTO disk is rusted to flywheel. sometimes you can break it with shock of heavy load on PTO starting implement or with tractor off and PTO engaged, clutch depressed, try to turn pto shaft and see if it is disengaging. use the higher pto speed, it will be easier to turn the shaft.
I noticed an empty bolt hole directly in front of the clutch levers travel. most tractors have a stop screw to prevent over depressing the clutch. Is your missing? I am not 100% sure foton 254 has a stop, but the hole looks suspiciously empty. If there is an access point to veiw the clutch and check that all the fingers are intact. a broken finger will stop the clutch from disengaging and the missing stop screw may have caused that... good luck.