Extremely weird clutch failure
 

So I'm driving home, car feels great, I'm running a new e85 tune that has finally learned the fuel trims. I downshift into 3rd for a soft speed bump and I grind the gear. NBD I thought, but as I put the clutch in to get ready for a turn, I could feel 4-5 distinct "notches" in the throw of the clutch pedal, whereas it felt fine literally 30 seconds before.

I go to give it gas and it has all the characteristics of a slipping clutch. Totally notchy clutch pedal very wtf. Once the clutch decided to grab it felt normal under light acceleration. I start to smell burnt clutch as I pull into my garage and and I can hear horrible metalic grinding noises. I popped the hood and lots of smoke coming from the clutch area.

Why would something like this happen so sudden? 68k miles on the clock original clutch original owner.

Did a bit more digging and it looks like it's probably the throw out bearing. It always made so much noise with the clutch depressed I wonder if it just gave up lol.

Yeah if it was making noise, it is the throwout bearing.
Probably the most common failure in these transmissions.
I'm wondering what caused the smoke.

Most older stamped fork Subarus have a stainless repair sleeve for the transmission snout where the plastic insert/bushing of the throw out bearing slides. The abrasive dust wears from the clutch wears the plastic and the snout and it becomes uncentered.

Dam now you got me paranoid.. I have a few thousand more miles on my car than yours (original owner too).

Is there any way to check for a failing (or about-to-fail) throwout bearing? Is it a gradual failure, like a worn clutch... or more of a sudden failure, like a timing belt breaking.

Just listen to it. If it starts to go there is no doubt.

Answered your own question. You upped the HP and torque and the bearing that was already going (as you said below) just said "screw it I don't want to live anymore".


My standard response to TOB issues is when you get it fixed make sure you upgrade the fork as well. Seems the fork on these don't do well with increased HP.

Thanks! Naturally, I immediately google "signs of a failing throwout bearing". It doesn't help that my clutch has been squealing like a baby pig since 30K miles ago.. I'll just have to listen for more weird noises from the clutch system.

Out of curiosity... Do you think the 2017 parts would play any difference rather than go aftermarket for the fork? As they did some "revisions" in the transmission. It may be too early to tell, but maybe there's a possibility the 2017 clutch fork and TOB could solve the problem so many of us are having? :iono: Would be a way to keep the warranty involved if you could convince the dealer to do something like that.

Depends more on when it squeals than if it squeals. Many of the guys that have noises just needed to lube up a bit.
I am pushing 100K and still have a perfectly silent TOB.

Possibly. Look up the changes. Pretty sure they only modified the bell housing and 6th gear. Could be wrong though. Maybe it was just 6th gear. Google knows.

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But, to be fair... I upped my HP and torque too, ~50K miles ago (also running on E85).

I've also 1) mis-shifted at high RPMs, 2) grinded the hell out of gears several times, shifting up & down, 3) never changed my clutch fluid til a few months ago, and I drove my car a few times over dirt/gravel road like a ATV 4-wheeler (ok, 2 of those times was unintentional)... among other things.

In other words, I've abused my car.. and it still loves me back! :D

The list of changes they provided was pretty clear and they made no mention of fork or TOB. I doubt it was changed but really hard to know for sure. They may have changed it anyplace along the line and we just never knew. I will have to take a look through the threads and see if this is predominately a 2013 issue or not. I never really paid much attention to the year when reading about all the issues.
The two things I have noticed though is that a lot of the guys with the problem are either new to MT and/or have HP increasing mods. The parts may be fine under normal use but may not take the learning curve or extra stress well.

Not saying for one second that increasing it will cause an issue just that it increases the risk of an problem occurring. There are loads of guys with huge increases that have not had a problem. Also many with stock everything that have so it isn't a black and white failure mode.


In this particular case, with the limited info at hand, the timing as stated and the fact there were indications for at least a while it is pretty safe to guess that the increase was the final nail.

Yep, agreed. It could be something seemingly insignificant as sand, salt, or other debris getting in the hydraulic system that can cause a massive failure (not saying this is the case for this particular failure).

86 owners, like other sports car enthusiasts, tend to drive cars harder and more unconventionally than 'normal' people.. it's assumed some of us will run into more unconventional mechanical problems too.

I was told at the dealer that water and debris can enter the transmission and affect performance, stating we do not have sealer units. If that is true, then yes, we are likely to experience some "issues".

If you downshift religiously as you come to a stop, you are just wearing the clutch disc out twice as fast. Brakes are cheaper. If you need to drop a gear, rev match.

The clutch fork part number goes back decades as well as the throw out bearing. (the wrx is a more substantial design). If you put in a stronger pressure plate, go billet on the fork.

How you drive will determine how much dust is created in the bell housing. This dust will wear at the plastic in the throwout where it slides on the snout. If your taking off in first, you should be able to release the clutch in 2-3'.

People feathering their clutch on the uphill waiting on the light to turn green won't get the optimum life out of their components.

If I see a red light from far enough and know that it won't turn green before I come to a stop, I put it into neutral and coast until the car stops and apply brakes as necessary. Bet it saves a bit of gas too. I never downshift unless I corner or know that the light will turn green before I come to a stop. And do people actually not rev match?

Almost nobody rev-matches. You will be surprised.

wow ... as soon as I learned how to drive manual, first thing I wanted to do was heel and toe cause it was so cool lol... I was heel-and-toeing in my second week. I have to say, the pedal setup on the 86 isn't the best for that...

The clutch is designed to be used to down shift as well as up shift. If I skip every other gear will my clutch last longer?

It actually uses more gas. Miniscule but still more. When in gear and decelerating on compression the engine is not providing fuel. It is when idling with the clutch in.
If I am moving my car is in gear. ALWAYS! I need to get out of somebodies way I don't want to have to take that half second to put it in gear I want to het the gas and go. Any professional driver will tell you it is always in gear.
Why take your car and turn it into a glorified soap box racer by coasting around?

I don't even use the clutch to shift, it's very easy and won't grind once you get the timing right.

Thanks for the responses guys!

Yes there were some signs before it actually failed. Earlier in the day before the failure I feathered the clutch in 1st going over a ditch and I heard what I thought was a suspension noise. I figured I would just re tighten the front suspension as maybe 70k miles made something come loose. Low and behold it was actually the drivetrain??

But other than the failure was totally random. Luckily I was 50 yards from home before I felt the clutch pedal lose any refinement it had left. I agree I think the extra torque might've been the last straw. Considering I was playing around all night to see if I find a torque dip lol.

I've called a couple shops and they're all trying to upsell me on clutch kits...$1,500 out the door. I tell them I want just the bearing replaced but is this a smart move? I think I still have about 50k miles I can squeeze out of the clutch. I'm wondering if I should just have them replace the bearing and have the clutch kit ready to go just in case something else is damaged?

My name must be "almost nobody"

Me as well. And pile of others on here.

I would be prepared for the worst and have the whole works ready. Not a given but the bearing can shear the fingers off the clutch when they let go. Better to have the parts you need then too have to wait once apart.

Re: downshifting

If you look at the edge of most pressure plates, there are usually three springs that hold the weighted plate to the housing. Not the clamping springs. They are directional to be in tension as when you are taking up the load. There is a possibility of bending them under compression like one someone drops from 5th to 2nd. The best example is an early M3.

I think the most frustrating part of this all is that this was my first manual car where I knew how to drive manual already. It was like a fresh start from learning on an e36 and e46 for 2 years. I treated my BRZ's clutch so well and even did things to do to preserve the TOB from 20k miles+.

Just what a waste it would be to have to get a new clutch after treating it so well. My biggest fear is every 70k the oem TOB is going to cause havoc inside of my clutch and I'm going to have to replace everything every time.

I want an oem clutch but is there a better TOB or even a revised version?

Has your car ever been in any accidents or mishaps at the shop? Not saying that's what caused your TOB problem.. just curious.

It's funny how crap happens when we take such care not to have it happen. I remember the first time I bought my tC back in '09, I was paranoid about rock chips on my car or getting my rims/wheels messed up. Within the first few weeks, I got a big crack on my windshield from rocks/object off a truck on the highway.. and a week later a flat tire & scrapes on my rim from a road debris. After that, it wasn't perfect anymore, so I drove my car like I didn't care = no more incidents.

I took the same approach after buying my BRZ, just drove it like I stole it.. no incidents so far. :fingerscrossed:

No I don't think so...you mean like a mechanic taking it for a hot ride or something?


And Tcoat just to be clear you think replacing the clutc fork with say the Velox unit will help against future failures?

Where does one acquire one of these repair sleeves? I've considered doing a custom rework of mine. Even if it doesn't fit I could get some idea.

My take on the fork upgrade is that it is not addressing the root issue. I pulled my transmission because I could feel my clutch pedal starting to bind for the reason discussed above.

I cleaned and regreased mine a year ago. Been fine so far but I'm waiting for the second coat of clutch dust to build up.

I taught him that.

:slap: ........ now, 8RZ ....... don't be given these guys any ideas ....... most of them have enough problems shifting gears ...... using a clutch ...... :eyebulge:

:D


humfrz

I was actually referring to guys that upgrade the clutch to something heavier.

Ya I wasn't clear. The fork upgrade is more important if you are going with a heavier clutch to deal with the increased HP. If sticking too OEM just make sure well lubed like Ultra said.

Me and a good group of owners I personally know with 2013-14 cars pushing 500+ hp and heavy clutches have never had problems with the fork... I feel like this "Fork is weak, replace it" mentality was just something manufactured from a few rare cases and it became popular. This is just IMHO.

There are always exceptions. There are many cases of fork failure recorded and it is a better safe than sorry situation as far as I look at it. Not like it is a massive cost.

That's true, not a massive cost and if you've already removed the transmission why not.