Jinma 254 clutch adjustment question

[greg_g]

Which takes me back to the original question, will I have to work with the main clutch adjustment bolts to move the release fingers closer to the throwout bearing ?

Well, you didn't actually ask that question before, but the answer is yes. I've done several of these clutches, but it takes a lot of typing to list all the steps. Check out this link: JMClutchAdj . If that doesn't do the trick for ya, c'mon back.

//greg//

 

[Turbo]

This is exactly as it is written. The diagram that is included shows adjusting bolt (11) as the clutch pedal stop bolt. Turning it in any direction will have no impact on the release levers, not to mention I have no idea how to measure the "96 .8mm" (and yes, it has 2 blank spaces between the 6 and the dot) between the fingers and PTO pressure plate with the clutch pack installed.

# 11 is wrong, it should read #24

 

[Turbo]

CSH before you throw adjustment at your tractor you need to analyze your problem first.
you say you have 530 hr on the tractor , and now the PTO is grinding when you shift in. Have you always had that problem for the full 530 hr? if not when did it start doing it? has your tractor been sitting awhile, and did it do it last year?
will it disengage at all ? how about an implement attached, will it disengage?
or just take it's time to stop.

I can't believe after 530 hr that you just need to make adjustment to make the problem go away. I think it more like corrosion / rust on the spines, and not allowing the disk to release all the way or even the clutch disk sizing to the fly wheel. were only talking about MM of movement here, and it wouldn't take much to stop it. It could also be a peace of clutch disk thats come off and wedged it self in between the surfaces.

Trying to fix a problem before you understand it will create more problems!

 

[CSH]

Turbo, thank you for the list of things to consider and for correcting what is in the manual. Bolt 24 (and not 11) makes perfect sense. Looking at the diagrams and descriptions online as well as looking inside my tractor I do have a pretty good understanding of how the 2 stage clutch works. I was surprised to see that much space between the release fingers and bearing when I removed the cover. I had never looked inside before so I can't say if it was this way from the beginning. I do understand that the gap should become smaller with wear and not larger.

It started doing this last year and has progressively gotten worse. I don't have any problems with grinding when shifting gears, and the main clutch plate holds really well and doesn't slip. There is also no slipping or unusual noises with the PTO engaged. I checked the roll pins and they are fine. Nothing sheared or backing out. The release bearing looks good and turns very smoothly. I was mistaken about the pedal stop bolt. After cleaning it off I can now see it is only threaded for about half of it's length. It is at the end of it's adjustment. The main clutch pressure plate slides back freely, but not far enough to fully engage the PTO pull rods and move the PTO pressure plate. The gap varies between 0.4 - 0.6 mm for all three bolts.

I don't think corrosion is an issue. This tractor is parked inside my basement when not in use and has never been rained on.

If there are no other obvious considerations, I assume adjustment of the main clutch bolts will be required, and I have a couple of questions about what I should use as a reference for measurements. As discussed earlier, I have no way to measure 96.8 mm for the clutch stack unless I split the tractor, and I'll certainly try the clutch adjustment before I do that. Should I:
1) make adjustments using the gap between the release fingers and bearing (and if I use this gap should I move the push rod back to it's original position when there was a 3/8" gap between release fingers and bearing),
2) make adjustments using the gap between the back of the fingers and clutch cover, or
3) move each bolt an exact number of turns?

I do realize this will affect the gap between the PTO adjusting nut and main pressure plate, which will also require adjustment. Right now this gap varies between 0.4 - 0.6 mm for all three bolts. I'm not apprehensive about making that adjustment (though maybe I should be) since it looks like one could easily use a feeler gauge to get all three gaps equidistant.

Thanks for everyone's help.

 

[greg_g]

I do understand that the gap should become smaller with wear and not larger.

If you're talking about the gap between the finger tips and the throwout bearing face, you have it backwards. I guess that JMclutch adjust link I provided above didn't suit your needs. First, the clutch pedal moves the throwout bearing carrier toward the clutch fingers - not the other way around. Then there's your earlier statement citing visible finger wear. That in itself widens the gap. And as the friction discs and pressure plates wear away, the spring tensions are relieved proportionately - also widening the gap. But maybe you're talking about some other gap (??)

Anyway, adjusting the clutchpack really boils down to preloading the springs again (taking out the slack caused by wear or maladjustment). Doing so necessarily moves the fingers toward the throwout bearing face, once again narrowing the gap in the process. In fact it's not unusual to have to compensate with the external linkage, and move the TOB farther back (away from the fingers). Unfortunately, working through the windows is a best guess procedure (relative to actually achieving specified stack height).

The PTO clutch should be adjusted first (1.2mm gap I believe), then the drive clutch (fingers) if necessary. It's important to make sure all three fingers are equidistant from the TOB face (+/- 0.1mm). When you're done working through the inspection windows, then finish up with the final linkage (2.5mm finger gap +/- 0.5mm) and stop bolt adjustments. The stop bolt adjustment isn't described in the book. But unscrew it to the point where the PTO grinds when you try to engage it with the lever. Then tighten the bolt to the point where the grinding quits.

//greg//

 

[Turbo]

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