Clutch pedal failure

[Boss2620]

I just returned from Willow Springs and experienced what I am calling clutch pedal fade away. The pedal would starts to develop a low release point and then eventually sticks to the floor. This would happen about 10 to 15 minutes into a 20 minute session and got worse as the day went on. If I let the car cool for an hour the pedal feel would improve but wouldn’t last long. It seems to me that the hydraulic fluid in the throw out bearing is boiling. I don’t have a transmission scoop yet but I’m considering it if it can truly help reduce the heat. Has anyone solved this problem with a scoop? The air temperature was in the mid 80’s but I’ve had the same problem on other track days when the temperature was cooler. I have a separate clutch fluid reservoir with dot 4 fluid. Also this time my pedal pressure seems to have lighten up by about 25% and hasn’t returned to my normal pedal feel although the car still shifts fine in normal street driving. Has anyone experienced anything similar, please let me know if you found a fix.

 

[Grant 302]

Pretty sure that's the typical upper RPM problem with the OEM Boss clutches. An aftermarket clutch is the only 'proven' fix.

Removing the assist spring in the pedal assembly might help a bit, since it contributes to the pedal sticking.

Flushing the hydraulic side and a vacuum bleed might also help some.

 

[domesticpower]

Did you just get the car or you've had the car for a while and it just started doing that? Did it only start doing that after the clutch fluid reservoir install?

I don't have a separate reservoir and have always used DOT4. Never had fade issues with the clutch, although I've heard of plenty of people who have (including one local '13). The problem went away after he switched to DOT4. Not all DOT4's are created equally so check what the boiling point of the one you are using is.

With that said, mine started acting similarly at one track day and the slave cylinder went shortly after so if you've had the car for a while and nothing has changed but it just started doing that, you might be due for a new slave cylinder (and clutch).

 

[Boss2620]

Did you just get the car or you've had the car for a while and it just started doing that? Did it only start doing that after the clutch fluid reservoir install?

I don't have a separate reservoir and have always used DOT4. Never had fade issues with the clutch, although I've heard of plenty of people who have (including one local '13). The problem went away after he switched to DOT4. Not all DOT4's are created equally so check what the boiling point of the one you are using is.

With that said, mine started acting similarly at one track day and the slave cylinder went shortly after so if you've had the car for a while and nothing has changed but it just started doing that, you might be due for a new slave cylinder (and clutch).

I’ve had the car since January 2013 and have had this same problem, although to a lesser degree, since I started tracking it three years ago. With the change in pedal feel a close look at the slave cylinder is in order. There is no loss of fluid in the reservoir so maybe an internal seal leak could account for the loss of pedal pressure.

 

[BigTaco]

If your going in to check the slave, I would strongly suggest that the clutch is replaced. That will eliminate any pedal problems....

 

[VoodooBoss]

Pretty sure that's the typical upper RPM problem with the OEM Boss clutches. An aftermarket clutch is the only 'proven' fix.

This. Nothing else is going to fix the clutch sticking to the floor.

 

[Mad Hatter]

+2

 

[Boss2620]

After considering all the options I’m going to go with the Exedy hyper single and the MGW race spec shifter. Now how to pay for it...