Learned a few things today about hydrolic brakes:
- If you develop a squeal, check for leaking fluid.
- Brake fluid DOT 3, 4 and 5.1 are proplylene glycol based and are compatible** but have different boiling points (important when a vacuum is pulled).
- DOT 5, is silicone based and not compatible with 3, 4 or 5.1.
Some brakes use mineral oil too.
** Note, when I say compatible, I mean they will not interact chemically and/or destroy your seals. They will have different properties though and may not function the same.