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brake fluid leak?

tomshobby

Yoda
Offline
This mainly has to do with my Midget although I have had similar experiences with my TR6.
When I got my Midget back on the road last Fall everything with the brakes work great. It as an entirely new system. No leaks, runs, or errors. When I backed it out of storage this Spring the pedal went to the floor. MC was empty and there were no brakes. I tried to find the leak and bled the system a couple times and they worked again but for a while I had to add fluid a few times.
Now after about 500 miles everything works great and it does not leak. I am running Dot 5. One thing I have noticed is that water does not seem to mix with Dot 5. Has anyone else had something like this happen? Been thinking about this for a while and wonder if there is any chance that some water may have collected somewhere in the system and froze. The freezing possibly causing a seal to loose shape and leak. Then after bleeding and using the brakes that seal might have returned to its original shape.
One thing I do know it makes me nervous and I will be watching this very close.
 
Yes, DOT 5 is hydrophobic, i.e. does not absorb water. I have not witnessed what you speculate upon, because my climate almost never reaches freezing temps, but I have witnessed rust through in master cylinders with DOT 5 due to water collecting in low spots. That makes me think your hypothesis is credible. The other issue is that depending on the rubber used for your seals, that they could be incompatible. Every British MC I have ever purchased has a bold disclosure on the outside of the box stating "warranty is void when using DOT 5".
 
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