PYO Clutch

[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.