Posted by Paul on July 25, 2000 at 21:53:21:
In Reply to: What brake fluid is best for a new hyd. system?... posted by Maurice on July 25, 2000 at 17:13:56:
You can go with eitehr Dot 3 or 4 which is standard or you can go with DOT 5 which is silicone.
DOT 3 is available widely and will go right in. However, it is hygroscopic and can absorb moisture from the atmosphere. That's why you need to replace it every couple of years with a flush.
DOT 5 won't abosrb moisture like DOT 3 will. However, if some gets into the system, it will settle out and can cause rust or even freeze in cold weather. I've also heard that some brake light switchs can fail after awhile. It won't mix with DOT 3 so if you're rebuilding the system, you'll need to flush it with alcohol before adding DOT 5.