Mr.ThunderMakeR

Just dropped my transmission to replace the throwout bearing. I had started hearing a squealing when pressing the clutch in and it got worse really quickly.

I just realized I didn't get a pic of the bearing, sorry I'll add it later. The bearing is definitely dead, the upper race came apart from the lower race as I was removing the bearing. I put it back together and it doesn't spin freely. But here is what I found, this black stuff all over the bell housing.




It also gummed up the fork and the base of the input shaft, you can sort of see it in this pic:




It is a cloth like material. I have some experience with high-rpm / high heat bearings in the helicopter industry. To me it looks like a heat related failure of a teflon liner in the bearing. It looks like it just disintegrated. Can anyone confirm whether the S2 bearing uses a teflon liner? I don't want to pull the new one apart that I just spent $55 on. Also note that the S2 has a different throwout bearing p/n than the S1. I think the S1 uses an old school ball-bearing style. Mine didn't have any.

Info about the car: it's an 09 with ~65k miles on it and probably 5-6 track days on it. However it's been 3+ years since I last did a track day. No issues with the clutch until very recently.

When I purchased the car, the service manager recommended I rev the car up before every shutdown. I regretfully followed this for years, revving the engine to 3k rpm for a split second before shutting off the engine. I usually did this with the clutch depressed. I feel like this may have something to do with the failure.

I described the sound to my service rep (not the same one from above) and he mentioned something about these bearings failing due to heat. I need to talk to him again and see if I can get more info.

9krpmrx8

iTrader: (46)

I have seen a ton of destroyed throw out bearings on RX-8's. It's weird because mine at high mileage looked fine but I have seen others destroyed in under 50k. I have an S2 trans in my car now, we shall see what how it lasts.

Mr.ThunderMakeR

Weird, I didn't see too many reports here about throw out bearings when I searched, maybe 3 threads. I need to do some more research, I'm curious if the Miata's with the same transmission as the S2 have had any failures.

I take it you're also using the newer throwout bearing with your S2 transmission? I'm curious if the S1 and S2 bearings are interchangeable.

9krpmrx8

iTrader: (46)

Yes I am using the new S2 one. The TB bearings do look interchangeable but on the three of us locally with S2 trans none of us bothered trying the S1 TB. I don't recall many threads about the TB failure but I have a few pics from various cars we have done clutches on here locally.

blu3dragon

iTrader: (1)

I'd guess the black stuff is from the clutch plate. A collection of fiber and dust that has worn off. I think this is normal, but you probably want to replace the clutch while you have it open...

Brettus

iTrader: (2)

Any thoughts on if the Koyo is more prone to failure when paired with an HD clutch ?

R3inSD

We needed a new throwout bearing in our 2011 R3 earlier this year and after just 37,000 miles. We had hoped that since it was so close to the 36k warranty mileage (but not 3 yr time of course), that Mazda would help us out with that. Unfortunately they only paid for the bearing itself... all the labor we paid out of pocket. The failure looks similar to what the OP described.

boricua13

Interesting, failure at 37k, mine is at almost that, might replace the clutch/bearing as a precaution.

blu3dragon

iTrader: (1)

I replaced my clutch a little over a year ago with an exedy oem one, along with the included throwout bearing. The bearing failed in around 12 months and 10k. That includes some track time.

I don't know if this was an uprated bearing or not - I can grab a pic if it helps.

One thing I did realize. I still had some air in my clutch lines after I replaced the slave cylinder at the same time as the clutch, and the result was there was no slack at the top of the clutch pedal once things warmed up. This meant the bearing was probably under some amount of load almost continuously.

So... make sure that your pedal is correctly adjusted, and there is always a small amount of slack when released, as not doing so will likely cause your throwout bearing to fail early.

ASH8

Agree with above, BUT, just be careful with adjusting Clutch Pedal away from the factory specs as you are asking for trouble.
US Miata (MX-5) owners are obsessed with adjusting the Clutch Pedal saying Mazda has it wrong, blah, blah, blah, what is wrong with you Americans!.
This coming from the land of the Auto trans ( .
How about adjusting your driving style (pedal/clutch uptake) to suit the car/product, rather than the other way around.
I can not remember any owners here ever complaining of Clutch Pedal travel and or wanting it adjusted, remember the Slave Cylinder is auto adjust and has been like that for past 35 years.

Back on the TOB, well again, a bad habit is to rest foot on clutch pedal or all the way to floor while in gear at traffic lights waiting, as you are using up your TO Bearing's life.

Only engage C Pedal once you are ready to change into gear and move off line.
I never had a noisy bearing or one that died young in over 44 years of driving MT's.