Here’s my predicament... I have an 07 Ranger 4x4 with 115,000 miles and a clutch that works fine, no slipping. But when it’s cold outside, the clutch drops about an inch. And shifting gets a little more notchy. I can pump it hard about 40 times and that fixes it, for the rest of my drive. Then it drops again. Until it’s about 40 degrees outside continuously. So once spring hits, it stays where it should be until fall. No fluid missing, no fluid under bellhousing. It’s been doing this for a few years now. I had it bled last last summer, and it was great, but once it got cold out, the problem came back. 

I’m pretty sure the slave cylinder has a small internal leak. The slave cylinder is inside the bell housing, requiring the transmission to be removed. At that point I might as well do a new clutch, too. I’d rather not yet, the clutch doesn’t slip at all. Everything works fine, but that slave cylinder, apparently. 

So should I try bleeding the clutch again to install this stop leak fluid? I’m wondering if it might swell the seals too much. Should I dilute it 50/50 with brake fluid? Thanks https://www.amazon.com/Bars-Leaks-1350-Clutch-Fluid/dp/B07MSSZ358/ref=asc_df_B07MSSZ358/?tag=hyprod-20&linkCode=df0&hvadid=343955370377&hvpos=&hvnetw=g&hvrand=447360010985108105&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9003173&hvtargid=pla-781564315396&psc=1&tag=&ref=&adgrpid=74841503648&hvpone=&hvptwo=&hvadid=343955370377&hvpos=&hvnetw=g&hvrand=447360010985108105&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9003173&hvtargid=pla-781564315396