I have a 1995 F-150. 4.9 I6 with a hydraulic clutch. Two years ago in the winter when temps dipped below 0 it began leaking brake fluid which dripped from the bottom of the bell housing and the clutch kept going soft. I continued to refill it when the resevoir ran low and if the temperature warmed up it would stop leaking and I wouldn't have to refill it again until it got cold. Eventually ended up replacing the slave cylinder and it worked fine for the next year and through the next winter. Now the second winter after doing this it has begun doing it again this time its leaking much worse. The brake fluid is again dripping out of teh bottome of the bell housing. Both of the times that it has sprung a leak have only been when the temperature dips steadily below 0 degrees. If the weather warms up, I won't have to refill it for awhile until it gets cold again. The Haynes manual calls for Dot 3 brake fluid for the clutch. It never had a problem during the 12 years my grandpa owned it before the first incident. Any ideas as to why it keeps leaking and why it is only when it is below 0 degrees? I don't want to have to keep replacing the slave cylinder every other winter so before I do it again here I was wondering if there is anything preventative measures I can take so I won't have to worry about it again?