Posted by George on Tuesday, March 11, 2003 at 8:26PM :
In Reply to: Brand new brakes system...Dot 3 or silcone? posted by dave on Tuesday, March 11, 2003 at 2:22PM :
DOT 4 is similar to DOT 3 but has less tendency to absorb water....they can be mixed. There is really no reason to use DOT 3.
Whether to use DOT 5 (silicone, not like DOT 3 or 4 which do not mix with it) is not so clear. Some say there is a greater tendency for DOT 5 to leak past the seals because DOT 5 does not swell the seals like DOT 3 and 4 do. Others note that DOT 5 fluids have been modified to correct this problem.
I have DOT 5 in one truck and it has never leaked. I am going to redo the brakes on my WM300, new master and all new wheel cylinders....and I am going to use DOT 5.