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2003 farm pro 2425 clutch adjustment

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pickinpough
Join Date: Sep 2010
Posts: 24 Scottsbulff Nebraska
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2011-07-11          179352


When I bought my tractor last year I was told by the dealer that he renewed both clutches. While I was performing wome routine mnt I decided to adjust some of the clutch pedal on my tractor. I noticed that the adjustment bolt with the clevis at the end was all the way in with no real adjustment left. I looked a the manual and did not see what was represented in the instructions on my tractor. I have a dual clutch affair one for the transmission and one for the pto but only see the adjustment bolt as being the single adjustment. does anyone have any ideas?



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2003 farm pro 2425 clutch adjustment

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greg_g
Join Date: Jan 2004
Posts: 1816 Western Kentucky
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2011-07-11          179359


First question has to be;
why did you think it needed adjustment in the first place?
Which is normally followed by;
do you actually KNOW what that adjustment does?

//greg// ....


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2003 farm pro 2425 clutch adjustment

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pickinpough
Join Date: Sep 2010
Posts: 24 Scottsbulff Nebraska
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2011-07-12          179371


I have 2" of pedal play, most clutches operate within 1" or less. When shifting it seems to grind slightly but the tractor does not jump as if the clutch is partially engaged. The clutch adjustment moves the clutch fork holding the clutch release bearing either in or out. If the adjustment is too far in the clutch will not fully engage, too far out and it will not completely disengage. The clutch release bearing is pressed against the "forks" of the pressure plate. The pressure plate is what pushes again the clutch disk to engage it against the fly wheel. When the clutch release bearing is pressed against the "forks" of the pressure plate it releases the pressure against the clutch disk and thus releases the clutch.

I know this is a very simple transmission and I would imagine that the sycro gears are for the most part marginal but I want to make sure that if this assembly is out of adjustment that I can make the necessary corrections. As you know, these assemblies will last a life time if properly maintained.

So with all of this, is the foot pedal adjustment excessive? Is it common to have some grind occasionally when shifting into different gears? I.E. first to second? and sometimes reverse to first. As a note I normally stop to go to second, and my transmisson oil is fresh and at the proper level with no leaks. I have no other noises.

Thanks Mike ....


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2003 farm pro 2425 clutch adjustment

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greg_g
Join Date: Jan 2004
Posts: 1816 Western Kentucky
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2011-07-12          179373


There are no synchros at all in this tranny. And pressure plates are what squeeze the friction discs between shifts. The flywheel face technically is one of the pressure plates. And expecting these clutchpacks to last a lifetime is overly-optimistic, especially if you have a front loader. But it appears you don't quite understand how this particular type clutch works, or grasp what specifically happens when you adjust that external linkage.

As you know, the clutch pedal is connected to the external clutch arm by that linkage. Moving the pedal moves the clutch arm which moves the throwout bearing carrier back and forth. Pushing the pedal moves the throwout bearing into the clutch release fingers, releasing the pedal pulls it back. It's the act of pushing on the fingers that moves the pressure plates away from the friction discs. And since this is a 2-stage clutch, it happens sequentially; PTO clutch for half the pedal travel, drive clutch for the second half.

So. With the tractor at rest, there should be 2.5mm gap (+/-0.5mm) between the vertical bearing face and each of the clutch finger tips. Adjusting that external linkage is what achieve the desired gap. Only way to do that is to observe and measure (the gap) through the clutch inspection port. Assuming there are no other problems, achieving the 2.5mm gap should also result in obtaining somewhere in the neighborhood of that 1" pedal play you mentioned. And depending upon how much you adjusted the linkage, you may have to adjust the pedal stop bolt as well.

As there are no synchros in this transmission, grinding between gears is unavoidable. First time Chinese tractor owners get to learn double-clutching whether they want to or not. But as the gear teeth wear over time, shifting between gears can become a bit easier. And by that time, your shifting technique will have improved as well. That said, grinding while trying to get INTO gear initially or when trying to engage the PTO is a problem that can usually be fixed.

//greg// ....


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2003 farm pro 2425 clutch adjustment

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pickinpough
Join Date: Sep 2010
Posts: 24 Scottsbulff Nebraska
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2011-07-12          179376


Now I understand the "two stage clutch" methology and your explanation helped me to understand what the manual was talking about. I will look more throughly for the inspection cover. I suspected this trans had no synchros so it was more of hope rather than expectation. I am old enough to remember the double clutching so I will have a very sort learning curve.
It also makes sense to me that half pedal I can engage the pto I just could not get my mind around this concept for some reason but it makes sense now. A car guy learning about tractors.

Thanks Greg ....


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richwaugh
Join Date: Mar 2010
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2011-07-13          179378


Mike,

Yes, the 2" of clutch pedal free play is excessive - 1" is about right. As Greg noted, the starting point for adjusting pedal free play is to set the clutch release bearing face to clutch fingers gap correctly. To do this you need to remove the clutch inspection cover - it is a rectangular plate located on the right side of the bell housing. If you have a front end loader installed on the tractor, the clutch inspection cover is "under" the right side loader tower. Actually, when installing the loader the clutch access cover is first removed and the loader tower bolted in its place. You have to remove that loader tower to get access to the hatch. With careful blocking you can do this without removing the whole loader from the tractor.

So - get access to the clutch and set the throwout bearing clearance to spec - 2.5mm, as Greg noted. YOu should look around on the Chinese tractor forums for the complete clutch adjustment procedure and do that while you have access. It only takes about an hour to do it carefully and it will greatly extend the life of your clutch components. One such tutorial is http://chinesetractor.proboards.com/index.cgi?board=jinma&action=display&thread=98 When that is complete check your pedal free play and adjust the take-up clevis as necessary to yield 1" pedal free play.

With practice you will find that you develop a muscle memory for the halfway point on pushing in the clutch to shift. When you go too far you're starting t release the PTO clutch and that increases drag in the whole works and makes smooth shifting less likely. On my JM304 I find that pushing in the clutch about 1/3 of the way yields the easiest shifting, but they all vary a bit from tractor to tractor.

On a tractor, unlike a car, you do not "feather" the clutch unless absolutely necessary - it just leads to excessive wear. You push it in and let it out with some alacrity. :-) Ground speed when working is adjusted by selecting the appropriate gear with the engine operating in its power band - about 2200 rpm for the 200 series tractors, I think. That rpm also yields the proper 540 rpm PTO speed. Diesel engines last longer and run cleaner at their designed rpm. Your tachometer probably has a green area to indicate the intended speed for your engine. Other than when you're traveling on the road, that's the speed your engine should be running at. ....


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greg_g
Join Date: Jan 2004
Posts: 1816 Western Kentucky
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2011-07-13          179382


Quote:
Originally Posted by richwaugh | view 179378
On my JM304 I find that pushing in the clutch about 1/3 of the way yields the easiest shifting, but they all vary a bit from tractor to tractor.
If/when the stack height is set properly, it should not vary from tractor to tractor. Don't know the spec for your tractor, stack height is the manufacturers' spec'd distance from the tips of the fingers to the other end of the clutchpack. Sometimes that's the PTO pressure plate, sometimes that's the flywheel face. That's the part that varies among tractors.

The fact that your split point is 1/3 travel vice 1/2 travel is correctable, but difficult to obtain accurately with the clutchpack installed on the tractor. On the bench it's a simple job, all the work is in splitting the tractor. On the tractor, it's a matter of adjusting the individual fingers in or out as necessary to shift the transition point in pedal travel to the 50/50 mark. But the aggravating part is finding that point among the 3 fingers AND making sure that all 3 remain the same distance from the throwout bearing face. But once successful on both counts, you will by default have returned the stack height to manufacturer spec. Harder on the tractor, but with patience and perseverance it can be done.

Note to other readers; the description above relates only to the Chinese 3-fingered clutches. Six fingered clutchpacks require a different procedure.

//greg//
....


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2003 farm pro 2425 clutch adjustment

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richwaugh
Join Date: Mar 2010
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2011-07-13          179383


The stack height *is* at factory spec, Greg. Fine tuned in place when new and then re-set when the tractor was split to replace a faulty gasket. At half pedal the drive clutch is fully released.

I just find that for the way I operate the tractor, I get the easiest release of the gear train (not necessarily the clutch) as the pedal hits about the 1/3 travel point. The gear train seems to like a wee bit of "drag" to slip smoothly, I would guess. The next step, of course, is engaging the following gear(s) and that happens at 1/2 pedal travel when the clutch is fully disengaged and the usual double-clutching drill is performed as necessary.

I had an old International deuce and a half that shifted much the same way, though of course it only had a single-stage clutch. It too liked a bit of clutch drag to disengage smoothly, prior to double-clutching to downshift. Upshifts were no issue on that rig - rarely needed the clutch if you were on top of things. I never had that trans apart, but I know it had no synchros and they sure felt like well-worn straight cut gears. It did have over 250,000 mountain miles on it so no surprise the gears were "worn in." (grin) ....


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2003 farm pro 2425 clutch adjustment

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greg_g
Join Date: Jan 2004
Posts: 1816 Western Kentucky
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2011-07-13          179384


Quote:
Originally Posted by richwaugh | view 179383
The stack height *is* at factory spec, Greg.Fine tuned in place when new and then re-set when the tractor was split to replace a faulty gasket.
Excellent. Because there were a couple of dealer-members here a while back who repeatedly insisted that stack-height was meaningless. I'm glad you saw through their hooey. Thanks for the clarification between 1/3 and 1/2 travel though, I'd never seen it expressed that way before.

//greg// ....


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2003 farm pro 2425 clutch adjustment

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kthompson
Join Date: Oct 2005
Posts: 5275 South Carolina
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2011-07-13          179386


I have enjoyed reading you two on the clutch. Been very good. ....


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2003 farm pro 2425 clutch adjustment

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pickinpough
Join Date: Sep 2010
Posts: 24 Scottsbulff Nebraska
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2011-07-13          179388


Very interesting, I did not realize that the first part of the clutch pedal travel was for the drive clutch. Here I am fully depressing the clutch for shift changes and then part clutch pedal travel for the PTO. The last few replys have been a real eye opener for me!
The dealer said he changed both clutch packs on this tractor before I bought it. I don't know his skill level but some of the other repairs he performed did not impress me. Greg had mentioned something about a stop bolt for the clutch pedal, my pedal hits the floor board so I suspect that it's missing. I haven't verified that yet but I do not remember seeing anything there. You can bet I will correct this.

With this new information, my ignorance to these tractor's operation might be more of the problem than the tractor itself. You guys have given me a detailed mental picture of what to do and what to look for if I suspect a problem exist after I change how I operate this tractor.

My sincere thanks Gentlemen ....


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2003 farm pro 2425 clutch adjustment

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greg_g
Join Date: Jan 2004
Posts: 1816 Western Kentucky
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2011-07-13          179393


Quote:
Originally Posted by pickinpough | view 179388
my pedal hits the floor board
Yeah, that's not right. The stop bolt by the way, is located on the bellhousing. You push the pedal which pushes the linkage which pushes the clutch arm which strikes the stop bolt. The stop bolt is adjustable, but it sounds more like yours is simply missing. Or else it's screwed so far in as to useless.

//greg// ....


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