Dry Master Cylinder - No Sign of Leak

[rob love]

I was going to say the same thing: the fluid will be more likely to leak at rest than at pressure, as the tension is not on the cups.

The leaked fluid will dry eventually, but will usually leave some staining to let you know where it left the system. Question is, was your system full in the fall, or near empty to begin it's winter rest.

Not all brake systems have the residual check valve. I know I have to remove them on the M135 when I use a M35 master cylinder, otherwise the brakes drag for 2 or 3 seconds.

You can also have cup expanders in the wheel cylinders to help prevent the seepage. It uses the spring pressure in the wheel cylinder to force the lips of the cup outwards.

I have always said the sitting is worse for these vehicles than using them. In my location, the temperature over the year will vary by almost 80°C over the year (we see almost -40 in the winter and almost +40 in the summer). The miracle is that the systems work at all. The other miracle, when I think about it, is that anyone chooses to live here.