Clutch engagement issue. Possible clutch cylinders upgrade?

[Sportsguy83]

Originally Posted by wu_dot_com

okay at the moment im considering a few options.

upgrade the like to SS lines. I think SS lines for STI should work.

meanwhile, i am also looking into upgrading the clutch master cylinder to OE STI cylinders. the stock BRZ/FRS have Nabtesco 11/16. the stock STI 2013 have Nabtesco 11/14. the increase in diameter of the WRX cylinders should be enough to handle any stage 1 pressure plate upgrade.

BTW which brand of SS line did you use?

I have good experience with goodrige SS brake line for bikes. so im leaning in that direction.

Before doing anything, I think you need to contact the likes of @Don@Accelerated, @Supermassive, etc. who have already installed aftermarket clutch kits (some up to stage 4 or 5) and see if they are having any problems. If they are not (and I believe they aren't), then you need to look at a bad pressure plate, incompatible with stock clutch disk or improper install.

Hope you get it squared out soon!

[Supermassive]

I was gonna speak up, but I am in no way an expert on this thing. I would definitely look into the clutch/pressure plate/flywheel/release bearing/shift fork before jumping to the conclusion that the master cylinder or hydraulic lines are going bad. I have a Stage 4 6 puck racing clutch in my car at the moment and am using the stock actuator with no ill effects and the pedal pressure is obviously greater but it's not nearly as bad as past cars I've owned.

Also your symptoms of difficult engagement lead me to believe that something is not right with the pressure plate. The stock flywheel is thick steel and the stock clutch disk just wont create the kind of heat required to warp it without you seriously slipping the clutch over a long period...if the smell of burnt clutch is common for you, you will definitely need to check the flywheel. I really don't know enough about your situation than the fact that you have an after market pressure plate. Did you have it professionally installed? Did you swap out the clutch disk (i'm assuming so since there's no point swapping a pressure plate and not the disk)? Was the flywheel resurfaced? Did they replace the release bearing (pretty sure aftermarket pressure plates use different release bearings)?

All these questions might shed a bit more light on your issue. I'm leaning towards the release bearing since it looks almost identical to the one I got from Clutchmasters for their pressure plate. The difference is a miniscule difference in thickness but from what it sounds like that miniscule difference could be what is causing you to have hard shifts when warm since the materials in the clutch will expand a little. Who knows?

[wu_dot_com]

Well to add to the information. My car was the prototype car for ACT when they developed their product. I have the prototype ACT HD pressure plate, prolite flywheel, and their performance street disk.

The entire system was installed and tested by ACT. So I think we can rule out unprofessional installation at the moment.

Meanwhile, I am not aware of the fact that ACT uses a Different throw out bearing. So I am going to assume they reuse the stock bearing.

I have 8K miles on those clutch at the moment. Mostly street or freeway, and occasional hard driving with no performance driving. I am also an experience driver, so I don't really slip my clutch often.

[wu_dot_com]

I've been doing a lot of searching in the WRX forum to see if I can find any similarity.

It seems like bad throw out bearing and deform fork seems to be the most likely contributes other than MC or slave leakage for performance clutch applications. Every once in while someone will get a bad pressure plate or clutch

[wu_dot_com]

Originally Posted by roddy

I believe there is a restriction or delay valve somewhere in the hydraulic system. Finding and removing it may help you out. I wish I had more info on this, but hopefully someone that knows the system will speak up with some advice. Many hydraulic systems have one in place to reduce shock loads to the drivetrain, and they often cause performance minded people a lot of greif.

I’ve consider the possibility of the delay valve to be at fault. However, my problem mainly manifest during down shift of a warm transmission. A faulty delay valve would probably have issue during both upshift and downshift.
I tried to do some other fault isolation as well following the clutch not fully disengage fault path. During normal driving at an onset of my symptoms, whenever I start to experience heavy resistance, I keep the clutch fully depress and increase/ maintain engine rev. the thinking is that if the clutch is not disengaging itself, it would act as if the engine is still couple with the transmission and thus would either slip or increase speed. I’ve experience no abnormal vibration, noise, or smell and the car decelerate as normal. I perform this test while the gear is neutral on its way into the shift gate and after I fully shift the gear.
One thing made me question the syncro is that during normal downshifting, I usually hear high PRM winding noise from the transition as I actuate the shifter into the gear prior to me releasing the clutch. I associate that winding noise with syncro speeding up to match the wheel speed. However when I experience my problem I usually don’t hear any winding noise.
Another interesting this is that during bleeding of my clutch MC and slave, I notice small amount of black dust like particle settling on the bottom inside the reservoir. I didn’t think too much of it at the time, but now that I think of it, it can be the pieces of internal O-ring deterioration.

[wu_dot_com]

Originally Posted by Supermassive

I was gonna speak up, but I am in no way an expert on this thing. I would definitely look into the clutch/pressure plate/flywheel/release bearing/shift fork before jumping to the conclusion that the master cylinder or hydraulic lines are going bad. I have a Stage 4 6 puck racing clutch in my car at the moment and am using the stock actuator with no ill effects and the pedal pressure is obviously greater but it's not nearly as bad as past cars I've owned.

Also your symptoms of difficult engagement lead me to believe that something is not right with the pressure plate. The stock flywheel is thick steel and the stock clutch disk just wont create the kind of heat required to warp it without you seriously slipping the clutch over a long period...if the smell of burnt clutch is common for you, you will definitely need to check the flywheel. I really don't know enough about your situation than the fact that you have an after market pressure plate. Did you have it professionally installed? Did you swap out the clutch disk (i'm assuming so since there's no point swapping a pressure plate and not the disk)? Was the flywheel resurfaced? Did they replace the release bearing (pretty sure aftermarket pressure plates use different release bearings)?

All these questions might shed a bit more light on your issue. I'm leaning towards the release bearing since it looks almost identical to the one I got from Clutchmasters for their pressure plate. The difference is a miniscule difference in thickness but from what it sounds like that miniscule difference could be what is causing you to have hard shifts when warm since the materials in the clutch will expand a little. Who knows?

after looking at the kit avaliable on ACT website, i am leaning tword the idea that they may have reused the OE pilot and release bearing. since i dont recalled having them back along with OE clutch assembly. consider the fact that they were working on my car in one week back in late june early july. they may not have a proper supplier for those parts at that time.

[arghx7]

Are you pushing the clutch pedal all the way to the floor when you shift?

[Supermassive]

Originally Posted by arghx7

Are you pushing the clutch pedal all the way to the floor when you shift?

If you are then it's definitely an issue with the pressure plate/release bearing, my clutch is fully disengaged with about an inch and a half of travel left to pressed fully in...

[wu_dot_com]

Originally Posted by arghx7

Are you pushing the clutch pedal all the way to the floor when you shift?

Originally Posted by Supermassive

If you are then it's definitely an issue with the pressure plate/release bearing, my clutch is fully disengaged with about an inch and a half of travel left to pressed fully in...

i have about 1.5 in to 1/3 of clutch travel left from total disengagement to the bottom of the clutch travel. this is true even when the transmission is hot.



i have also performed another clutch dragging test following instructions below

• With the vehicle running, disengage the e-brake so it can roll.
• Push the clutch pedal all the way to the floor and hold it there.
• Turn off your launch limiter so the engine can hit the rev limiter. You MUST DO THIS!! If you do not, then there is no point in performing this test.
• Shift the car into 1st gear.
• Rev the engine up, while the clutch pedal is depressed all the way to the floor, until you feel the car start to move forward.

http://www.jackstransmissions.com/pa...kills-synchros
i got the information off of EVO fourms with users expereince ACT clutch issues.

i have done the clutch dragg test when the engine is both cold, and HOT (after i've experience lockout), the car did not move in either test conditions and my engagement point after the clutch is hot still have 1.5in to 1/3 of travel left.

[gmookher]

Still cant tell if this is a user install issue or if its product issue

who else makes a clutch for our cars besides ACT?

[wu_dot_com]

Originally Posted by gmookher

Still cant tell if this is a user install issue or if its product issue

who else makes a clutch for our cars besides ACT?

since the clutch was installed by ACT and the problem didnt developed until close to 7K miles since installation. at the moment i am ruling the installation error as a low probability.

meanwhile, I am not so quickly to dismiss the entire ACT product at the moment. since i only have their prototype pressure plate which may not be the configuration as the release version.

besides ACT, there are currently clutchmaster, exceedy, who also makes the clutch and some small shops here and there.

Moster clutch is ready to release their product soon as well.

of the 3 well known avaliable options, exceedy is probabbly the safest bet. they are also the OE clutch manufacture. meanwhile Clutch master release their clutch eaily on in the game (approx late June) while ACT took their time to complete the full development before releaseing their product (mid October if my memory serves me correct).

P.S. my clutch was made late June earily July. Mine was the first car application fitted with actual hardware for this platform.

[Supermassive]

Originally Posted by wu_dot_com

since the clutch was installed by ACT and the problem didnt developed until close to 7K miles since installation. at the moment i am ruling the installation error as a low probability.

meanwhile, I am not so quickly to dismiss the entire ACT product at the moment. since i only have their prototype pressure plate which may not be the configuration as the release version.

besides ACT, there are currently clutchmaster, exceedy, who also makes the clutch and some small shops here and there.

Moster clutch is ready to release their product soon as well.

of the 3 well known avaliable options, exceedy is probabbly the safest bet. they are also the OE clutch manufacture. meanwhile Clutch master release their clutch eaily on in the game (approx late June) while ACT took their time to complete the full development before releaseing their product (mid October if my memory serves me correct).

P.S. my clutch was made late June earily July. Mine was the first car application fitted with actual hardware for this platform.

A clutch isn't too difficult to make for a specific car, my Clutchmasters FX400 is way beyond well made. Not to knock ACT, of course I haven't put anywhere near the miles on my clutch as you have, so honestly who knows how it will hold up once i have 5k plus miles on it. The clutch drag test doesn't necessarily sound like it accounts for shifting conditions...all it does is makes sure your clutch slave cylinder has enough throw to disengage the clutch completely. When you are driving the transmission spins with the rear wheels so the clutch disk is spinning between the friction surfaces of the flywheel and pressure plate, which during normal shifting could be slower or faster than how fast the clutch disk is spinning.

The clutch drag test doesn't spin the clutch disk, so it doesn't take into account that factor. Have you tried driving your car to about 20 mph in first and pressing your clutch in and coasting to a stop...if it doesn't decelerate smoothly then it could be a clutch issue. If it does decelerate smoothly with the clutch pressed to the floor, then it may be a synchro issue and you will likely have to bring your car into a dealer to be looked at. Without actually driving your car I can't help too much because I don't personally have any idea how it "feels".

Wish i could be more help.

[wu_dot_com]

Originally Posted by Supermassive

A clutch isn't too difficult to make for a specific car, my Clutchmasters FX400 is way beyond well made. Not to knock ACT, of course I haven't put anywhere near the miles on my clutch as you have, so honestly who knows how it will hold up once i have 5k plus miles on it. The clutch drag test doesn't necessarily sound like it accounts for shifting conditions...all it does is makes sure your clutch slave cylinder has enough throw to disengage the clutch completely. When you are driving the transmission spins with the rear wheels so the clutch disk is spinning between the friction surfaces of the flywheel and pressure plate, which during normal shifting could be slower or faster than how fast the clutch disk is spinning.

The clutch drag test doesn't spin the clutch disk, so it doesn't take into account that factor. Have you tried driving your car to about 20 mph in first and pressing your clutch in and coasting to a stop...if it doesn't decelerate smoothly then it could be a clutch issue. If it does decelerate smoothly with the clutch pressed to the floor, then it may be a synchro issue and you will likely have to bring your car into a dealer to be looked at. Without actually driving your car I can't help too much because I don't personally have any idea how it "feels".

Wish i could be more help.

Thanks for all your inputs, it's been very helpful please continue to do so as this is part of the priceless learning processes.

Now bak on topic, I have done the rolling clutch drag test as you suggest too at 2,3,4,and 5th gears. Under both hot and cold conditions the rate car slow down with the shifter in gear with clutch fully depress and the shift in neutral and the clutch releas is about the same. No abnormal vibration or noise was observed.

Meanwhile I'll try to do as many test as anyone can think up before I contact ACT after the new year. Depends on how that conversation goes, I'll keep you guys posted.

[wu_dot_com]

ive just talked to the design engineer at ACT. As always, he've been extrimely helpfull in making time avaliable for me to go drop off my car for them to look at the clutch assembly.