Chrome Master Cylinder Help

Discussion in 'Wheels' started by BuddyK, Feb 15, 2012.

  1. BuddyK

    BuddyK Member

    I have a new chrome HD master cylinder kit 46418-05A for a '05 to '07 with dual disc using DOT 4 fluid. My bike is a '04 ElectraGlide with dual disc's using DOT 5 fluid - it calls for kit 45281-99D.
    According to the service parts lists for both, the only difference's are the brake line sealing washers and the internal repair kit is the same part number but has a different letter on the end - the '05 is #45072-96B (DOT 4) and the '04 is #45072-96C (DOT 5).
    I know the fluid types are not interchangable, but are the seals the same and will they work with the DOT 5 since they are new and have not had any fluid in the cylinder yet?? Or will I have to replace the internal seals with the ones for the DOT 5??
    Thanks in advance for your responses!
  2. Bodeen

    Bodeen Well-Known Member Staff Member Moderator Contributor

    I'm sure somebody will come along that knows for sure. Until then it seems to me that the seals for DOT 5 would not hold up on DOT 4 fluid. Since DOT 5 is silicone based. However, I cant imagine the silicone based DOT 5 would hurt the DOT 4 seals. That is just a gut feeling but I could be completely wrong.
  3. Breeze3at

    Breeze3at Well-Known Member

    Buddy; Both my '92 and '07 (dot 5 and dot 4 fluid) service manuals state to clean all master cyl. components with denatured alcohol so you should have no problem. As a note, on the recommendation of a certified FORMER HD mechanic, my buddy changed his '07 dot 4, to dot 5. He just drained, refilled and bled the systems, no cleaning. He has had had to rebuild both master cylinders because of greenish gunk that formed in the master cyls. and calipers.
  4. R_W_B

    R_W_B Senior Member

    I agree with both the previous replies. DOT 5 is less aggresive than 4 so as long as your system if flushed and clean you shouldn't have any problems.