well, in prep for my ape install I purchased some DOT4 brake fluid, as with my past experience with motorcycles MOST use 4. well, as luck would have it apparently HD uses dot5......whats the difference? will dot4 not work?....I'm thinking no, as I had a hell of a time bleeding them prior to the realization that it uses dot5.

 

It depends on what year your bike is. My 05 uses DOT 5 and my 06 model uses DOT 4. Whatever you do, don't mix them, they are not compatible.

 

DOT-4 and DOT-5 can NOT be mixed.
The correct fluid for your bike should be embossed on the master cylinder cap.

 

dot 5 is silcone based ....will not corrode parts..such as fenders/tanks etc..
dot 4 will ruin everything it touches.

I have dot 5 in my 1978 honda ..been there 5 years..works good..
also in my 91 sportie,and 03 fatboy
best thing other than agm batteries for motorcycles..
if you put in dot 3, o 4 just flushthe system with dot 5..you do not have to take apart master , or wheel cylinders..
I even put it in my boat trailer brakes ...01 model ..no problems

 

Okay great, yeah I drained it all out once I realized the marking and I'll be picking up some 5 this week. It will definately be flushed in the bleeding process.