how to bleed master cylinder

[George Selby]

At 12:02 AM 3/26/03, you wrote:
>I had to remove it, clamp it in the
>vice, operate the plunger with a brass drift, and hook up the 2 plastic
>threaded plugs which were included with the MC and route 2 included
>pieces of tygon back into the MC reservoir.  While pushing the plunger
>with the drift, I was able to get all the air out of the MC piston.
>This took about 40 pumps on the MC, but once the bubbles were gone, I
>hooked up the MC, and I was done in about 10 minutes.


I am in the process of doing a major brake overhaul on my 78 F-150
(includes all new metal lines and SS lines to replace any rubber lines, a
new MC and Brake Booster from a F-350, front brake calipers with larger
pistons, and larger rear brake cylinders, as well as new pads all the way
around.)  Anyway, on the new MC were different instructions that I had
previously encountered.  Included with the MC were two plugs that screwed
into the holes where the line goes (no little tubes to run back into the
MC.)  You install the plugs, put the MC in a bench vise, and use a brass
drift to press in the plunger.  Repeat until you no longer see bubbles
rising in the reservoir.  I found it worked best when I pressed about 3-5
times, then let it sit a couple of minutes, then pressing another 3-5
times.  The rear half bled almost instantly, but it took about 20 minutes
to get all the air out of the front half.  The instructions claimed this
was much easier and quicker than the old 'tube' method.

Once bleed, then you install it in the car (with plugs still attached) The
pedal should be rock hard.  Then install one line at a time.  Whoever said
you couldn't install it without getting air in the lines was
correct.  However, if you are quick and have all the tools ready to go when
you remove the plug, it will only allow a little fluid out.  The MC will
stay bled unless you let all the fluid run out of it (keep this in mind
when bleeding the little bit of air out of the lines and don't allow the
reservoir to run empty.


George Selby
83 Audi Coupe GT
gselby4x4 at earthlink.net