What break fluid do you use? Dot 4 or dot 5?

 

Owners manual says 5, so that is what I use.

 

My 2003 SE Deuce calls for DOT-5 and gets it. My 2008 Street Glide calls for DOT-4 and thats exactly what it will get when it needs it.

 

My 05 Ultra service manual says dot 4. I just went to a single sided 6 piston HHI. Should I go to dot 5?

 

My opinion is that you are better off sticking with the DOT-4 because it would be almost impossible to completely purge your system of the old stuff. Both have their advantages, but a heavy bike like an Ultra, I would sure feel safer with the less spongy DOT4

 

Use whatever is specified for your bike, as brake fluid isn't something to be taken lightly. DOT4 and 5 are not compatible and should not be mixed in any concentration. If a changeover must be done the old fluid must be completely purged. Older bikes take DOT5, changed to DOT4 several years ago. Not sure of the cutoff year. Anyone know?

ABS bikes will need to stay with DOT4 since DOT5 has different compression characteristics and may cause the ABS to malfunction.

 

My '07 uses DOT 4......

 

If you use break fluid your brakes will fail. If you use brake fluid they work fine. Using the correct fluid is important.

 

My bad, brake not break. The master cylinder, line and caliper are new.

 

I would still use DOT4.