Clutch pedal pumping up - clutch slip (maladjusted)

[Tom1200]

This post is more for posterity than anything else.

 

I ran my 1200 at VARAs British Extravaganza at Buttonwillow last weekend. Start the last lap the clutch started slipping, it was so bad I pulled in rather than take the chequered flag. After letting the car cool, I jacked it up and sure enough there was no play in the slave cylinder push rod. 

I adjusted the rod so there was a bit of extra play in it. The next day I ran the 20 minute morning warm up and it was fine but there was less play than when I started. So for good measure I put some more slack in. The car made the 9 lap final without issue.

 

Once I got home I checked and sure enough the pedal stop was improperly adjusted and the master cylinder push rod wasn't returning all the way. Obviously the piston inside the master not returning all the way was pumping up the system.

 

Live and learn kids.....................the funny thing is I can't remember when I last adjusted the stop. 

 

[Stoffregen Motorsports]

As I've said before, a misadjusted clutch master (or even slave cylinder) can actually damage the crank and main bearings.

 

Glad you caught it.

[Tom1200]

It's probably been maladjusted for some time but the installation of a new clutch disc, which was just thick enough, used up the last bit of play. I have not touched the pedal stop in years.