Just recieved my new chrome handlebar controls (Custom Chrome) for my 06 Softail. Kit is for all H-D's single disc models 96 and up. On the master cylinder it says to use DOT5 only. I know my 06 has DOT4 and that the two cannot be mixed. I don't see why I could'nt use Dot4 in a M/C that hasent had any fluid in it. I checked the new M/C and it is bone dry. Any suggestions or ideas would be appreciated. Thanks....

 

Didn't we see you in another forum? Flush the system completely with dot4 to remove any residual dot 5 from the factory and then fill/bleed/check operation/ride.

 

DOT 5 is a better fluid.....I am not sure exactly, but IIRC it is much less hygroscopic, is not as harmful to paint (I would not try that one), has a much higher boiling point, and is made with silicone. I dont know....but if it was my bike and it called for DOT 5.....thats what it would get. My 03 FXSTD-SE calls for DOT 5.....and thats what I would use if needed.