|The master cylinder can
be accessed by way of the left front finder well or, on standard beetles,
you can also get to it by removing the gas tank. (This gives you a
little more room to work)
|Place a piece of card
board and a rag under the master cylinder to catch any brake fluid
that might run out of the lines.
|Pull the line(s) that
feed the master cylinder out of their rubber plug(s)
|On 67 and later bugs use
the same method.
|Unplug the wires or plugs
that go to the stop light switch(s). 66 and earlier bugs have 1 stop
light switch, 67 and later bugs have 2 since they started using a
dual circuit master cylinder half of which fed the front of the car
and half fed the back. It doesn't matter which of the wires goes to
which side on the stop light switches that only have two terminals.
The stop light switches that have 3 terminals usually have a plug
that only goes on one way. In 1968 they came out with a warning light
that told you if half of the dual master cylinder wasn't working.
This light was turned on by a third switch in the middle of the, now
obsolete, 68 & 69 only master cylinder. This can be replaced with
a later model master cylinder just tape up the wires that would go
to the center switch. If you want your warning light to work you'll
need to use the later model stop light switches that have three terminals
and modify your wiring. We show you how to do this in Vol. 9 Wiring
of our instructional video series.
|The 1967 and later dual
switches used on the master cylinder are shown here.
|Take loose the metal lines.
You may have to turn the flare nut back and forth a few times until
the metal lines no longer turn with it. This may save you the cost
of new lines and the time and effort it takes to replace them.
|Move to the inside of
the car and remove the two 13mm bolts that hold the master cylinder
in place. The old master cylinder can now be removed.
|Note: There should
be a tube like metal spacers over each bolt. If yours aren't there
you need to get/make some so you can tighten the bolts without their
head disappearing through the hole in the double panel. This will
make it much easier the next time you replace the master cylinder.
|Swap the stop light switches
from the old master cylinder to the new one. Of course now is a good
time to replace them if they are old and rusty. If the new master
cylinder doesn't come with rubber plugs these will also need to be
swapped or new ones bought.
|Put the new master cylinder
in place lining up the push pin as you slide it into the hole. There
should not be any pressure on the master cylinder caused by the push
pin if the brake pedal is all the way back. If there is then the push
pin needs to be centered in the master cylinder or readjusted.
|Start the metal line fittings
by hand to prevent cross threading. Then tighten them the rest of
the way with a flare nut wrench.
|Plug in the stop light
wires and pop the feeder lines back into their rubber plugs.
|Move to the inside and
tighten the two 13mm bolts, with their spacers, into place.
|Refill the reservoir and
bleed the air out of the master cylinder by having someone on the
inside pump the pedal a few times and then hold it down as you loosen
and tighten the top line fitting. Repeat until no bubbles come out
with the brake fluid.
|On 67 and later bugs both
circuits (front and rear) will need to be bled using this same method.
|If at this point your
pedal feels spongy it means you've got air in the lines that go to
your wheel cylinders and these will also need to be bled. Note:
While bleeding the brakes make sure you maintain a good level of brake
fluid in the reservoir. Reconnect the battery ground strap and
you're done. Replacing the master cylinder, as well as the rest of
the brake system, is shown in detail in the video Vol.4 Brake Maintenance
available from Bug Me Video.