Throwout Bearing Sleeve Seals on B7100

[chetcromer]

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)

 

[BadDog]

The seal lip edge on the shaft generally goes toward whatever it is trying to retain.

 

[chetcromer]

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.

 

[BadDog]

Sorry, I really can't tell enough to be sure.

 

[chetcromer]

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

 

[BadDog]

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.

 

[Apogee]

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?

 

[chetcromer]

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!

 

[benben]

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

benben

 

[vtmbz]

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?

 

[North Idaho Wolfman]

The outer and inner ball joint coupling is held on by a spring pins.

 

[vtmbz]

So does that mean I have to detach the transmission tunnel from the transmission to get at those snap rings?

 

[Dennis]

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?

Ah yes I did this job last year. You separate and roll back the rear end about a foot and this is enough to allow you to pull the shaft out of the tunnel ,fit the seal and replace the shaft.

It's a little awkward getting that seal in straight but persist.

 

[vtmbz]

Thanks to Australia for being awake while I sleep!

THe only time I post here is when I dont want to do something. (As in: do I have to...) This all started as a groaning clutch that turned out to be a disintegrated pilot bushing.

I replaced both the propeller shaft seals and now I suppose I should go on and get that last seal in there--no mention of any of this in the shop manual. Probably better not to know in advance that you're going to have your tractor in pieces the size of a lunchbox before you're done with the clutch.

 

[Dennis]

Thanks to Australia for being awake while I sleep!

THe only time I post here is when I dont want to do something. (As in: do I have to...) This all started as a groaning clutch that turned out to be a disintegrated pilot bushing.

I replaced both the propeller shaft seals and now I suppose I should go on and get that last seal in there--no mention of any of this in the shop manual. Probably better not to know in advance that you're going to have your tractor in pieces the size of a lunchbox before you're done with the clutch.

No problem. While you have everything apart also check and replace the drive shaft ball coupling that is in front of the transmission case. When I checked mine it was shot.
Worth putting alignment marks on shaft and coupling before separating.