Here's why you don't use a plastic throwout bearing (and how clean should I get the bell housing?)

RiverDawg24

RiverDawg24

TJ Enthusiast
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Jul 31, 2019
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Arkansas
I tried to make a title Chris wouldn’t have to change.

So I heard a pop last week, had play in the clutch fork. I thought the clutch fork retaining spring broke. But nope! The plastic ear sheared off the plastic housing of the throwout bearing.

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My Jeep has 143,000 miles on it but I don’t think this is original equipment. This clutch does not look high mileage to me.

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Here is a pic of the TOB that came in the Luk clutch kit. Seems they reinforced it but still using plastic.

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Here’s the cast Timken TOB I am going to use unless someone sees an issue. It has a cast body.

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Lastly the inside of the bellhousing is coated in gunk. How much effort should I put into cleaning this?

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I am replacing EVERYTHING while I have the transmission out. Clutch, fork, TOB, pilot, pivot ball, clutchfork spring.
 
  • Wow
Reactions: RustyAutoholicGuy and Chris
The real question is who thought it would be a good idea to even make a plastic throwout bearing in the first place, honestly?

I personally like the look of that Luk throwout bearing in terms of durability.

Since my new TJ is the first manual transmission TJ I've ever owned, I'll be following this to see what others recommend with more experience. When the time comes to do my clutch, I want to do it right!
 
That new LUK throw out bearing wouldn’t bother me, looks much better than what you removed. Looking at the friction disc rivets tells me that there’s not many miles on that disc. Personally I would clean the inside of that bell housing, but it’s not required.
 
Vinman said:
My jeep has about 75k on it and I replaced the second throw-out bearing a year ago with the cast Timken bearing. Plastic has no business being buried so deep in a drivetrain
Click to expand...

Exactly what I was going to recommend. Timken is a quality name in bearings.
About 12 years ago I needed to replaced the stock TOB so I also replaced my clutch/pressure plate, pilot bearing and flywheel.
The LUK kit came with a TOB from a manufacturer that I was not familiar with so I sourced a Timken TOB to use.
The LUK kit worked flawlessly in Moab for 12 years before I sold the Jeep.
 
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CharlesHS said:
Not to jinx you... but don't be surprised....
Next time use the Timken TOB instead...
Too many horror stories about know offs and Chinese parts
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This has nothing to do with TJ’s, but I remember damn near all the clutch kits for small block chevys were coming with steel pilot bearings. When you disengaged the clutch the input shaft would continue to spin because of the galling of the input shaft against the steel bushing. The solution was to take a magnet and make sure the bushing wasn’t steel. Everyone would use a national oil impregnated bushing, I think the trade name is oilite. Just trying to get as much information as I can to do a failure analysis. Would like to see all the clutch parts to form a final opinion.
 
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So on the note of pilot bearings. This is what was in my Jeep instead of a pilot bearing. It’s brass. Thoughts? I bought a Timken pilot bearing too. BTW, whoever said pack the hole with bread and use pressure to remove this is a freaking genius. Worked amazing!!

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RiverDawg24 said:
So on the note of pilot bearings. This is what was in my Jeep instead of a pilot bearing. It’s brass. Thoughts? I bought a Timken pilot bearing too. BTW, whoever said pack the hole with bread and use pressure to remove this is a freaking genius. Worked amazing!!

View attachment 163718
Click to expand...
Do you have a stroker engine by chance, because that bushing is for an early model 4.0L
 
Daryl said:
What did the LUK kit come with?
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Roller bearing. First thing I checked.

I’m going with the Timken.

I will say I’m not impressed with the press fit of the bearing. Not loose but definitely not tight. I’ve only done a few clutches in jeeps. So may be normal??
 
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