Re: Can anyone tell me what this is?
 

Jet, I am pretty buff.

Slowbubblecar, Yeah i installed my (homedepot created) one last night and it didnt help the situation.

Anyone know how to tell (besides leaking fluid) whether the master cylinder, or the slave cylinder is bad?

Re: Can anyone tell me what this is?
 

I recently did a clutch on a GS-T and it was having the same problems as you listed. We tried everything bled like crzy for about 3 hours and still nothing. We went out and bought a new slave cylinder and bled again and everything worked perfect.