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Discussion Starter #1
The BBC on my 1991 M-series has started to have a few issues. Are there any tips on the removal of the BBC from someone who has done this? I have the repair manual, which mentions the special clutch retaining tool, then the use of a puller to remove the assembly from the crankshaft.

I recall reading on this site before some people saying they had not used the clutch retaining tool, but I couldn't find the posts through the search function. I also don't have a puller, so if that is needed, I may have to use the loan-a-tool from Autozone.

The symptoms exhibited are:
Occasional noise when the engine is running but blade is not engaged (sometimes makes a growling/grinding noise like a bad bearing, or sometimes a rattling sound, other times it is quiet like it should be)
The last time I used it, there seemed to be some dragging on the engine when the blade bail was not engaged. The blade was not spinning, but there seemed to be some load on the engine.
Once the blade is engaged, I haven't noticed anything abnormal.
 

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Sorry I can't really help with info as I'm new to the BBC scene. You should be able to find that style puller(universal) from Sears or rental places like you mentioned. Make a cardboard template of the bolt pattern needed for removal to take with you when you shop for that puller. Looking forward to reading a successful job from you and other helpful hints on this as I'm sure mine will need attention also someday.
 

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Discussion Starter #4
Here is the current status:

Removed the BBC without any special tools, or a puller. I simply removed the center bolt, and then reinstalled the blade, and gently pulled the unit off with the blade.

So that leaves me with this:



That extra little circle in the lower left is supposed to be the bottom race of the bearing at the top of the BBC unit, seen as a close-up in here:



As I was working, I found some other metal pieces that appear to have formed the cage for the ball bearing that has failed. Here is some more of that carnage...



So that leaves things looking like this:



You can see the bearings randomly spaced in the race since the cage has failed. I removed the three shoulder bolts as the next step, which gets me to the step of needing to remove the key from the crank. This is currently the step in which I am frozen. I have not been able to successfully remove the key yet.

Here is the assembly as it currently stands, and the last photo showing the key that I can't currently remove.





I have a used BBC that I am going to see if the bearing appears good on it. I'll probably try to pick back up on this job another night later this week. Any suggestions on getting the key out of the end of the crankshaft?
Thanks...
 

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Too bad the bearing cage was never sold separately. I'm pretty sure that little thing is why most end up getting tossed. As far as I know they were sold as a complete unit only and they are not cheap.

The two that I have pulled both came apart easily without any kind of special tool or puller of any kind...pretty easy, straight forward job actually.
 

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Discussion Starter #6
Too bad the bearing cage was never sold separately. I'm pretty sure that little thing is why most end up getting tossed. As far as I know they were sold as a complete unit only and they are not cheap.

The two that I have pulled both came apart easily without any kind of special tool or puller of any kind...pretty easy, straight forward job actually.
Indy,

Did you have any trouble getting the key out of the crankshaft? It won't budge on my mower. Any words of advice?

Thanks...

I did find my used BBC from my box of spare parts, and the bearing on the engagement arm appears to be in good shape. I popped the dust cover off the engine side of the bearing , and repacked it with Mobil 1 grease, so I think I'm good to go once I get the key out and can slide the engagement arm and BBC clutch cover off the crankshaft.
 

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I don't really remember, its been awhile..Have you tried a pair of side cutters to grab it and pry up like with a flywheel key?
 

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Discussion Starter #8
I've tried almost everything I can think of with the exception of maybe heating it up with a propane torch.

I put some penetrating oil on it and left it to try it maybe tomorrow night..
 

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The last time I used it, there seemed to be some dragging on the engine when the blade bail was not engaged. The blade was not spinning, but there seemed to be some load on the engine. Once the blade is engaged, I haven't noticed anything abnormal.
Listening in since I have an M that has similar issues.
 

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Hmm. Id bet the key is just wedged in there right now. Hopefully your penetrating oil did the trick. If not het it up like you said and see if expands enough to just wiggle it loose.

Good pics btw, I have 3 M's. Two of which are BBC. I like my non BBC as in tall wet grass it doesn't bog like the others.......
 

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Those keys are almost pressed in and very tight. They can be removed through tapping and prying with punches or chisels, but be careful as to not damage the shaft. I had to replace the key on the input shaft on the trans in my 10591 when I had it apart for servicing. I trashed it after having to remove it to replace the input shaft bearings which were worn.
 

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I just did this job recently. The key was difficult to get out, but I used some small chisels and a hammer and was able to tap it out after heating it for a bit.

Once you get it out, you'll need a puller to remove the top bearing cage - on mine it was EXTREMELY tight on there - required considerable effort to remove.
 

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Discussion Starter #13
I have successfully completed the R&R of the BBC unit. I was able to get a small chisel tapped under the key and drive it out today. Maybe the penetrating oil helped some.

After removing the key, the engagement arm, and clutch cover came off my mower without much problem. I didn't need a puller to remove them. I used the engagement arm from the used BBC unit that I had, and reused all the other BBC components that were original to my mower. When I started the mower to test the BBC, I was surprised at how quiet the engine was. I had gotten used to some rattling/buzzing/whirring noises when the blade wasn't engaged, so that tells me that the bearing has likely had problems for quite some time. It now sounds as good as if it had a new BBC unit. There is no audible noise other than the engine running, then when the BBC is engaged, the blade spins up with no drama.

All in all, as Indy said earlier in this thread, working on the BBC is not as daunting a task as it seems from reading the repair manual. It really was relatively straight forward. The special tool and puller mentioned in the repair manual were not needed at all on my mower. In what seems like a bit of irony, the single step that was the hardest for me is just plainly stated "Remove key from crankshaft" in the repair manual.
 

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The Sea of Green Machines
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Good Job! I have a spare new one for F series that is much the same but the upper bearing section is made for the opposite direction rotation. So if that is the part that fails my stuff wont help me much. However the bearing looks just staked in and may be replaceable.
 

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The Sea of Green Machines
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Super job Al! Did you restake the new one or is it a nice press fit?
 

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Didn't need to restake it. I did use some of the Loctite green colored bearing lock on it. When it's together all the pressure is pushing the bearing inward anyway.

Also used a thin coat of anti-sieze on the crankshaft where this upper bearing slips on. It's all pressed together tight to the crank shoulder by the clutch and that BBC bolt & lock washer, so the upper brng doesn't need a press fit.
 

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The Sea of Green Machines
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You didnt happen to note the part number of the bearing you used did you?
 

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The Sea of Green Machines
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Thanks Al!
 
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