Definately rebuild the rear also. If you've got gunk in the front, I'll bet
it's also in the rear. You should also consider replacing the rubber brake
I've always used a fresh, unopened can of brake fluid for flushing the
system. A quality DOT3 like Castrol LMA is fine. DOT4 is also compatable
with DOT3. It has a higher boiling point and absorbs less moisture, but it
is MUCH more hazardous to paint.
My experience with DOT5 (silicone) brake fluid is limited, but all bad. Two
weeks after I changed over to DOT5, I was picking pieces of master cylinder
seals out of my front calipers!
From: Bart Niswonger <firstname.lastname@example.org>
To: email@example.com <firstname.lastname@example.org>
Date: Monday, February 21, 2000 6:51 PM
Subject: brake flush or rebuild?
>Howdy -- I am in the process of fixing up the brakes on my 74 1/2 RBB.
>Nothing was seriously wrong, just getting ready for a long trip. This
>is my first time going through this process, and I have some
>I was planning on replacing all the rubber hoses, rebuilding the front
>calipers and replacing pads & rotors, i.e. leaving the back alone.
>When I opened up the calipers I found about a 1/4 inch of gunk in the
>bottom. Is this normal?
>Given that there is gunk in the calipers, it seems reasonable that
>there is gunk in the MC, in the lines, and in rear brakes. Should I
>rebuild them too? How can I flush the lines? What should I flush
>I really appreciate all the sage advice that flows on this list.
>Brakes are a popular topic, with many differing opinions, which is
>what I think is really valuable - so many voices. I haven't seen
>anything to answer my questions exactly, and I am hoping I can spur a
>bit of a debate from you!