Water won't cause this issue. It will lower the fluid boiling point. The resultant vapor causes a low mushy brake pedal. It will also promote corrosion in the metal lines.
I was thinking fluid contamination or rust in the hose brackets that constricts the hoses, but the comment about the rubber seals in the master cylinder caps growing is proof of fluid contamination. The number of comments about replacing EVERYTHING in the hydraulic system with rubber parts is exactly correct. Anything with rubber seals must be replaced at the same time and all the metal parts and lines must be flushed with brake parts cleaner and dried. The type of rubber used in brake systems is not compatible with petroleum products. Any part not replaced will allow contamination to leech out into the new fluid and the entire system will be contaminated again.
Antilock brake hydraulic controllers are full of rubber seals too.
Caradiodoc
Friday, August 7th, 2009 AT 9:45 PM
