Question about the clutch/TOB
 

So first off let me say this may be a dumb question. But here it goes...

Today i drove a friends 2013 BRZ. For comparison i have a 2015 FRS. His has roughly 35k miles and mine barely over 11k. To both of our surprise the clutch pedal felt completely different. His was much stiffer than mine. My "throw" in the pedal is almost effortless compared to his. Both of our clutches are stock. What exactly would cause such a massive difference in the feel of the pedal?

Did he take out the clutch spring?

Your friend's clutch is worn more than yours is. As the clutch disc and the pressure plate wear, the angle of the fingers of the clutch cover spring change such that the leverage you have is decreased. When your buddy puts a new clutch in his car and steps on the pedal the first time he'll think there's something wrong because the clutch will be so easy to push in.

@Tcoat or @Ultramaroon........ please help the folks out ........ I sense many misconceptions ........:eyebulge:


humfrz

I'm curious enough to want to ask your friend if he's done anything to his clutch.

There is something to @jcw99's explanation. I have felt that change but it has never been radically different.

Yeah in 2013 a lot of FRS/BRZ owners adjusted their clutch pedals which could change the feeling (it was one of the first DIYs for our cars actually)


While we are talking about clutches and TOB. I heard mentioned in another thread that you can buy a more robust TOB for the FRS if preferred. Which TOB would fit the FRS and be a little more "beefy"?

My driveline textbook mentions that if you have an extremely hard pedal to check the pedal mechanism and the fork for binding. It says a hard pedal can be caused by a blocked compensation port in the master cyl., due to improper pushrod adjustment or the piston binding in the bore. Can also be caused by swollen piston cups in master and/or slave. The last thing mentioned is the worn assembly which was the case on my Toyota pickup awhile back. I replaced the disk, p/p, fork, TOB and whatever. When I first stepped on pedal after that I thought we put the wrong pressure plate in or something it was so easy but then I remembered that I had driven a new truck and it was also so easy to push in.

Blocked compensation port will cause much greater issues than a heavy pedal. The clutch will start slipping way before then.

A common failure mode for the toyobaru clutch is binding of the TOB on the trans front cover. If the clutch pedal was dramatically stiffer than normal, I'd consider that first.

Could be clutch fluid thats beyond its limit and your''s is fresher.

@humfrz, I could blissfully have ignored this thread but now I'm doubling down on my beta blockers.

Trans fluid. Ive heard alot of stories on here of a 'night & day' difference from changing fluids.

If I take into account the subjective nature of "night and day," "massive difference," and my own "radically different," I concede that until I feel it for myself or we dyno the different scenarios, all of these theories are plausible.

But........I just knew you could handle it ....... :D


humfrz

That which does not kill you... :cheers: