as everyone stated, flush out, get new lines if you plan on switching back to DOT3/4.

DOT 5 can cause sludge and brake failure when mixing with 3/4, it is silicone based..Usually once you go through it with DOT 5, you def. should not switch back to DOT3/4 because of the mixture that has happened, unless you change out all the lines.

 

I could swear I used DOT 5 in my 05 Fat Boy per the service manual.

Did HD switch the fluid they use?

 

I know 07 Softail service manual is DOT 4.

Around 2005 for certain models they switched..Yours I think was DOT 5..switched Softails in 2006.

DOT 4 - For use in '06-later VRSC™, '07-later XL, '08-later XR, '06-later Dyna® and Softail®, and '05-later Touring models.

DOT 5 - Fits all models (except '05-later Touring models, '06-later VRSC™, Dyna®, Softail® and '07-later Sportster® models).