My guess is the new brake fluid destroyed the seals in your master cylinder. Castrol GTLMA is the best fluid for Girling brake components. GTLMA is the only fluid I have found that will not attack the natural rubber found in most Girling brake and clutch components. You should now rebuild your slave cylinder and probably take a look at your caliper seals as well. -- Mike > Hello List, > > 2 years ago I replaced both my master and slave cylinders with new ones from DMC > houston. About 6 months ago I noticed my master cyliner leaking by my foot, and > the clutch fluid decreasing. I purchased a new master cylinder from grady, and > a new slave cyliner from specialtauto, so i would have them on hand and waited > until christmas break (now) to change cylinders. I just changed the slave > cylinder, and started on my master cylinder, I noticed the fluid in the master > cylinder resivoir has turnned to a black jelly. There is quite literally 1 inch > of just black thick gel mush in the resivior. I had changed fluid when I > changed cylinders previously and used valvoline synpower (DOT 4). Was this the > cause of my premature failure? Had I waited too long to change the fluid (2 > years)? I have the SS braided clutch line, and a fuel grade line that runs from > the resivoir to the master cylinder, so I would not suspect contamination from > the hoses. I went and bought 2 bottles of valvolineABS (exceeds DOT 3 and DOT 4 > standards) fluid, but I am not sure I want that fluid in my clutch system now. > Do other people use this fluid for their clutch system? > > Thanks > > Joe P. > > VIN 17167 6808