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Throwout bearing failure on ACT HDSS kit after 15k mi.


Nolmers06LGT

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I've been experiencing a rattle and vibration for a few weeks now but I was hoping it was something else. I had a coworker look at it with me, and confirmed that my TOB is toast. It sounds like my bearing is completely dry0 it's only a matter of time before it comes apart. This is the TOB that comes with the ACT HDSS kit, which I installed about 15k ago because the OEM TOB went with the typical squeal. The noise has not progressed to the typical squeal, but is an intermittent rattle, so I think I have a little bit of time before it grenades.

 

There have to be a few causes to this failure:

-Too stiff of a pressure plate causes premature wear

-No clutch return spring to pull the TOB off the diaphragm spring

-Any other possibilities??

 

That said, here are some things I will plan to do at a minimum to prevent this from happening again:

-Clutch return spring

-Tranquil sleeve kit

-Possibly swap out ACT Streetlite FW to WRX single-mass FW

-Look into a different clutch

 

I really can't afford to spend the time pulling the tranny now, let alone if this happens again. If I can keep my clutch/flywheel I'd like to, but if it means preventing failure its worth moving on.

 

My goal is to find all of the possible causes, take preventative precautions, and hope that this doesn't happen again in the future. Any advice would be greatly appreciated.

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sorry to hear.. is your buddy a subi guy?

 

No, but he's a guy who has 15 cars right now, and has been his own mechanic for a long time. I haven't had a chance to record the sound, but if you've heard a bearing once its lost all of its grease, you know the sound I'm hearing. It sounds like the cage that houses the balls is scraping the races. There's no mistaking it for something else- I have a bearing that is failing- somewhere. It just so happens to only make the noise when pressing in the clutch and blipping the throttle.

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Seen this more than a few times. Best to get it out and replace with a TSK-3 as soon as possible. Chances are the quill is grooved now (and it might have been before the ACT install).

 

Why isn't a clutch return spring on these cars? What is actually pulling the TOB off of the pressure plate?

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Post up a sound clip. Slight possibility that you've got a bad pressure plate too.

 

I'll try to get one at lunch. That wouldn't surprise me. This is getting frustrating- I'm getting tired of chasing issues. I'm starting to think I'd be smart to sell it before I have to deal with motor/turbo/transmission issues. Going with a reliable DD and a weekend toy seems like a much smarter option.

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FWIW - going to the Group N bushings really intensifies the transmission noises. I think mine (noises) is a combination of failing ACT PP, worn ACT TOB (w/41K on it) and the solid bushings/mounts.
- Pro amore Dei et patriam et populum -
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FWIW - going to the Group N bushings really intensifies the transmission noises. I think mine (noises) is a combination of failing ACT PP, worn ACT TOB (w/41K on it) and the solid bushings/mounts.

 

I'm glad I'm not the only one who installed the ACT TOB instead of the TSK3 sleeve kit.. What makes you think your PP is failing on top of the TOB?

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Because I have seen pressure plate springs lodged between the plate and disc, completely out of the plate.

 

I have also seen TOB's completely grenade and find the ball bearings between the pressure plate and disc.

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Because I have seen pressure plate springs lodged between the plate and disc, completely out of the plate.

 

I have also seen TOB's completely grenade and find the ball bearings between the pressure plate and disc.

 

Well here's to hoping for the best... I got lucky last time and my TOB held together until I removed it. With any luck, it will do the same this time and I can salvage my clutch kit. If the clutch is bad, this will NOT be a quick repair, as I will need to spend some time researching a better solution. I'll probably end up swapping out to an OEM SMFW, and some clutch with good reviews meant to handle around 320hp. Hopefully I don't have to go that far though.

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Because I have seen pressure plate springs lodged between the plate and disc, completely out of the plate.

 

I have also seen TOB's completely grenade and find the ball bearings between the pressure plate and disc.

 

See my post on craptastic ACT clutches..Finger broke and wedged between the disc and PP.

"Gimme mines Balboa...Gimme mines".....Clubber Lang - Mr. T
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If you compress a BNIB CSC, you'll find that there is a return spring internal to the cylinder. This will create a slight "push" against the clutch fork. Several members on here have mentioned putting a light spring on the clutch fork to hold tension away from the TOB and potentially extend the life of the TOB and your transmission snout. Definitely go with the TSK-3 since you're in there already.

 

More info on the return spring here

- Pro amore Dei et patriam et populum -
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Thanks for the link, as I'm definitely going to be doing the return spring. I'm just concerned that the return spring won't be enough- It takes a lot of force to push the fork to the home position, almost like there is hydraulic pressure constantly being applied. Is this possible?
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I replaced the CSC on my 98 LGT and spring tension inside, before adding hydraulic fluid to it was pretty stiff. Adding the fluid made it even more resistant. I put a spring on that one too and will likely add a spring to 05 LGT when I redo the clutch/TOB in the near future, just to reduce wear on the TOB.
- Pro amore Dei et patriam et populum -
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I guess I was thinking something was failing because I can't understand why the engineers at Subaru would design a clutch system that doesn't relieve pressure on the TOB. Is this an issue on all LGT's? If so I may develop a bolt on solution so you don't have to drill the clutch fork
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Well, the car is back together and driving. I'm pretty happy I was able to pull the transmission and reinstall within 2 days... Only hangup was troubleshooting the CSC, which is still inconclusive. My TSK3 kit's TOB is still riding the pressure plate.

 

I installed the clutch return spring, but too stiff of a spring would not allow the CSC to retract properly. Once the spring was light enough to not bind the CSC, it wasn't strong enough to pull the TOB off of the pressure plate.

 

Where do I go from here? There's all new fluid in the lines and the system has been bled, so that's out. My thought is that the CSC is wore out to where it binds and doesn't want to retract properly. I'm hoping that with a new CSC I can put a heavier spring in and not bind the CSC. I still can't wrap my head around why there would be a spring in the CSC moving the cylinder in the direction of the actuation. I'm sure there's something I'm missing, but I would think you'd want a spring to retract the CSC, not constantly apply pressure to the clutch fork.

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You shouldn't need a return spring or Subaru would have engineered this with the car. What you need is to dump that POS ACT clutch for something a little bit better engineered and manufactured. I hate my ACT, my OE was a better clutch. It doesn't hold power as advertised, the PP fingers are uneven and they make the TOB wobble when the clutch is disengaged. The effort to push this clutch in is an insult to my left foot. I will go to my grave telling everyone to avoid this clutch.
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You shouldn't need a return spring or Subaru would have engineered this with the car.

 

By that logic:

-You also shouldn't need to get off the stage1 tune, because Subaru's map doesn't cause burnt valves.

-You shouldn't need to replace the oil pickup, because it definitely doesn't crack.

 

I give a lot of credit to the engineers at Subaru, but there are going to be flaws. The engineers don't get everything right all of the time, which is exactly why we have companies producing aftermarket parts like the TSK3 sleeve kit.

 

I find it hard to believe that Subaru intended the TOB to spin the entire time the engine is running. In my eyes, this is exactly why we have problems with TOB failures. STI's don't have this issue, and I've been told that there is a clutch return spring from the factory.

 

What you need is to dump that POS ACT clutch for something a little bit better engineered and manufactured. I hate my ACT, my OE was a better clutch. It doesn't hold power as advertised, the PP fingers are uneven and they make the TOB wobble when the clutch is disengaged. The effort to push this clutch in is an insult to my left foot. I will go to my grave telling everyone to avoid this clutch.

 

That's an easy solution, considering I just put the transmission back in the car. :rolleyes: The clutch is fine.. The effort to push in the clutch WAS a bit much, but after swapping to new fluid and bleeding the system, the pedal feel is nice. Clutch engagement is nice and smooth. If the clutch is bad, I'm driving it into the ground because I'm not pulling my transmission again. I also don't have an issue with the clutch not holding power, but I'm only stage2. If I could do it over again, I would get a different clutch.

 

That said, the clutch isn't the reason my slave solenoid is applying pressure to the pressure plate. I may be wrong, and my apologies if so. I just find it hard to believe that the TOB would be intended to function this way.

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You missed the point, YOU SHOULD NOT NEED A RETURN spring. ( Any you don't need a stage one flash either. ) I've had three different clutches in my car and only the ACT has TOB noise.... and you can watch the fork wobble. I never needed a return spring with any other clutch. The pressure plate fingers are uneven. The clutch is a piece of shit.

 

The TSK sleeve kit doesn't fix anything but driver stupidity (by not getting the clutch fixed when it started making noise). I'vee seen plenty of TOB failures caught early that did no damage to the trans snout. However I will agree the TOB has to be the cheapest design I have ever seen.

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You missed the point, YOU SHOULD NOT NEED A RETURN spring. ( Any you don't need a stage one flash either. ) I've had three different clutches in my car and only the ACT has TOB noise.... and you can watch the fork wobble. I never needed a return spring with any other clutch. The pressure plate fingers are uneven. The clutch is a piece of shit.

 

The TSK sleeve kit doesn't fix anything but driver stupidity (by not getting the clutch fixed when it started making noise). I'vee seen plenty of TOB failures caught early that did no damage to the trans snout. However I will agree the TOB has to be the cheapest design I have ever seen.

 

Actually, when my TOB went the first time it did no damage to the trans snout. I caught it before the bearing failed. After installing the sleeve kit, there was a noticeable difference in how the clutch feels, and the clutch engagement is smoother. Even though the TSK3 kit didn't fix my issue, I don't regret swapping it out.

 

I'd be curious to know if, on a different clutch, the TOB rests on the pressure plate. I've been pointing my finger at the clutch actuation because even if you depress the slave solenoid to allow the TOB to clear the PP, the internal spring in the CSC returns the TOB to the PP. I'm curious if this is my issue, or if it really is my ACT clutch. I understand your point, but the PP has nothing to do with the CSC pushing the TOB onto the PP.

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