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Old 06-17-2013   #1
chetcromer
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Default Throwout Bearing Sleeve Seals on B7100

I'm overhauling the clutch and seals on my B7100-D 4x4.

We have the diagram below, but because the old seals were basically no longer in existance, we can't figure out which way the seals go.

We're replacing parts # 3 and # 4 on this diagram. Any help? We're not sure which direction the rubber seal should point - toward the front or toward the back.



(we're actually replacing a lot more than that, but these are the two seals thus far that we can't identify which way they should go since the old parts are not identifiable)

Last edited by chetcromer; 06-17-2013 at 09:23 AM.
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Old 06-17-2013   #2
BadDog
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Default Re: Throwout Bearing Sleeve Seals on B7100

The seal lip edge on the shaft generally goes toward whatever it is trying to retain.
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Old 06-17-2013   #3
chetcromer
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Default Re: Throwout Bearing Sleeve Seals on B7100

Quote:
Originally Posted by BadDog View Post
The seal lip edge on the shaft generally goes toward whatever it is trying to retain.
Thanks, I think that helps. I know these pics are a little blurry, but I think I'd say the first has the lipped edge pointing up. Agreed?



and the second here has it pointing down.



I apologize for the quality... was out in the barn for a long time today and didn't notice how blurry these were.
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Old 06-17-2013   #4
BadDog
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Default Re: Throwout Bearing Sleeve Seals on B7100

Sorry, I really can't tell enough to be sure.
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Old 06-17-2013   #5
chetcromer
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Default Re: Throwout Bearing Sleeve Seals on B7100

Quote:
Originally Posted by BadDog View Post
Sorry, I really can't tell enough to be sure.
Yeah, I know... terrible pics. By "lipped edge" you mean the edge that has a little wider lip along the edge... lol... to use your own words. Just making sure my understanding of the term matches yours.

Thanks,

Chet
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Old 06-17-2013   #6
BadDog
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Default Re: Throwout Bearing Sleeve Seals on B7100

Hmm, how to describe...

If you look at how the seal works and flexes to keep in contact with the shaft, you'll notice that the "wiper"(?) surface has to expand just a bit over the shaft. There will generally be an be an offset fulcrum in the seal material that sort of allows the lip to flex. Sometimes there is even a "spring" inside the lip to hold it on the shaft. The seal/wiper "lip" sticks out a bit to one side of the fulcrum area. That's the side that goes toward the material being restrained.

To think of it another way, if you put it on backwards, any pressure or movement of the restrained material will tend to get under and lift the wiper lip letting the material (oil, grease, etc) past. If you put it on right, any pressure will tend to push the wiper into the shaft harder, thus holding the material back.

There are seals for which this is not true, but for power shafts in wet transmissions (etc), this is generally correct.
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Old 06-17-2013   #7
Apogee
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Default Re: Throwout Bearing Sleeve Seals on B7100

The seal has a spring on one side that helps hold it against the shaft. If the seal were being installed on a transmission input shaft for example, one would install the side with the spring so it's facing towards the inside of the transmission.

In other words, the spring side is the side that would be bathed in transmission oil, hence my comment above about installing it so the spring faces the inside of the transmission.

BadDog is right, the fluid pressure on the back side of the seal helps it seal tighter against the shaft.

Make sense?

Last edited by Apogee; 06-17-2013 at 09:42 PM.
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Old 06-17-2013   #8
chetcromer
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Default Re: Throwout Bearing Sleeve Seals on B7100

Quote:
Originally Posted by Apogee View Post
Make sense?

I think we got it - but then again I'm not the most mechanically minded of the bunch fixing my tractor. THANKS.

What started as a clutch replacement now has my tractor split at both the clutch and the transmission to machine a sleeve to keep the pilot bearing snug in the flywheel and a complete overhaul of the joint where the shaft meets the transmission. Not what I intended, but I sure feel like I know this 30 year old tractor more than I did when I bought it now!


Last edited by chetcromer; 06-17-2013 at 05:00 PM. Reason: I can't spell.
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Old 06-18-2013   #9
benben
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Default Re: Throwout Bearing Sleeve Seals on B7100

Hi chet
good job and nice pic. your 30 years old B7100 look better as your Pikup.

benben
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Old 09-08-2013   #10
vtmbz
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Default Re: Throwout Bearing Sleeve Seals on B7100

I'm doing the same repair down here across the border.... I want to replace the large seal that goes on the outside of the throwout bearing holder but cant get it over the propeller shaft without removing the propeller shaft from the tractor.

I pulled the little cotter key and pin and got the shaft loose, but the parts diagram is blurry: how is the the outer coupling ball attached to the propeller shaft? How to remove the outer coupling ball?
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