Hi all wonder if anyone can help when driving my rx8 on a hot day after about an hour of driving my clutch pedal goes spongy and seems to bite a lot lower down to the floor and the pedal seems to have a gap at the top before any pressure is felt but when it's cooled down it's fine,it's only done 37000 miles could this be the clutch or clutch fluid problem

 

Mazda used ethanol during the installation of the slave cylinder boot.
At hot ambient temps (~85F) the ethanol becomes vaporized and expands.
As pressure in the boot increases, the piston is pushed back into the cylinder body.
The result is a gap between the piston and the pushrod and presents excessive free play and difficulty disengaging the clutch.

Ethanol is no longer used in the manufacturing process, but can affect '04-'06 RX8s produced before May 1, 2006.
Mazda's part number for a new cylinder is F151-41-92XB

 

Great answer Jon!

 

Thanks for your reply thsts spot on it's a 2004 model wiv very low mileage I will source the part thanks again

 

Just like to say your advice was spot on I sourced part and had it fitted by local garage and the clutch is spot on and it's like driving a different car thanks once again

 

Nice work, Jon! :-)