Southbend Clutch TOB failure - Curious how many people have had this happen???

**Monty23** · 02-12-2015 05:17 AM

Has anyone else had a TOB failure where the metal spacer that is glued on has separated from the rest of the TOB? I just saw zillarob had a TOB failure too and I am curious if anyone else has gone through this ordeal. My clutch looked great at 13K miles other than the TOB...

**julex** · 02-12-2015 05:32 AM

FWIW CM TOB equivalent is not even glued, it just sits tight on top of the TOB body and you can separate it by hand very easily.

The TOB still works fine, right?

**rnagy86** · 02-12-2015 05:42 AM

Extending a TOB from the top is always a bad bad idea.

**julex** · 02-12-2015 06:19 AM

Originally Posted by rnagy86

Extending a TOB from the top is always a bad bad idea.

Well, this or plastic/fiber faced TOB... It looks to me like all aftermarket "metal" TOBs are really what pictured above. When you build TOB the bearing part has to be somehow affixed to the part that presses against clutch fingers?

Is reality both plastic and metal TOBs are the same part for bearing base and only the top is different.

Monty,
I would still replace it for peace of mind but chances are you drove on this TOB for last 10k miles and were no wiser about it :)

**Monty23** · 02-12-2015 06:38 AM

Originally Posted by julex

Monty,
I would still replace it for peace of mind but chances are you drove on this TOB for last 10k miles and were no wiser about it :)

Well, the last 2K miles or so I had been having an issue where when I would slowly slip the clutch (like I always do) to take off in 1st from a stop and the clutch would instantly grab 100% and the whole car would lunge forward. I would immediately press the clutch back in and the car would be fine. This happened about 5-10 times randomly over the last 2K miles and it would never do it twice on the same day.

The day before the clutch started slipping, the same scenario as above happened except when the car lunged forward and I pressed the clutch back in, the car continued moving forward and I heard grinding noises from the trans area. I had to quickly throw the shifter in neutral. Then the car behaved normal again right after.

I pulled the clutch due to it randomly starting to slip at WOT.

Disk has plenty of meat

Flywheel and Pressure plate had maybe a .01" of wear each.

Anyways, my brand new SB stage 4 clutch should be here today and I am going to mate it to my new TTV flywheel.

**julex** · 02-12-2015 07:15 AM

what's the clearance between PP and FW @ bolt area when you lightly (a little beyond finger tight) bolt it together? After 12k miles I would totally expect your clutch to be done and thus slipping. Appearances are very deceiving with paddle style clutches since they wear cosmetically very lightly... and remember that there is no SAC in your clutch so once that gap is only ~2-3mm, the clutch will slip since diaphragm can't develop full tension anymore (it is extended beyond nominal).

Not exactly the same clutch but look at this tilton graph for their twin clutch:

High clamp clutch loses all holding capacity at 2mm of wear... for example. This is where SAC rules, it keeps ramping up spacer betwee PP surface and diaphragm to keep diaphragm at its maximum tension by taking up the space where wear normally removes it.

**Monty23** · 02-12-2015 07:27 AM

Originally Posted by julex

what's the clearance between PP and FW @ bolt area when you lightly (a little beyond finger tight) bolt it together? After 12k miles I would totally expect your clutch to be done and thus slipping. Appearances are very deceiving with paddle style clutches since they wear cosmetically very lightly... and remember that there is no SAC in your clutch so once that gap is only ~2-3mm, the clutch will slip since diaphragm can't develop full tension anymore (it is extended beyond nominal).

I would love to measure the clearance and I certainly will in another 10K+ miles when the new clutch is done lol. Maybe I'll try an AMD next.

Just to be clear, you are taking the clutch disk out of the equation and just want measurements of the wear on the friction surfaces of the FW and pressure plate? I should have measured everything before I shipped the clutch back to SB for a rebuild...

**julex** · 02-12-2015 07:32 AM

Originally Posted by Monty23

I would love to measure the clearance and I certainly will in another 10K+ miles when the new clutch is done lol. Maybe I'll try an AMD next.

Just to be clear, you are taking the clutch disk out of the equation and just want measurements of the wear on the friction surfaces of the FW and pressure plate? I should have measured everything before I shipped the clutch back to SB for a rebuild...

ok, I missed that you're rebuilding the whole thing, I thought you wanted to stuff everything back together with TTV wheel without touching the Disc or PP