[click to enlarge]
the years, the parking brake on your BMW may become unadjusted and fail to
perform properly. The adjustment of the brake shoes is an easy process, and
shouldn’t take you more than an hour to accomplish.
The first step is to
raise the rear of the car and remove the two road wheels. This will allow
you access to the rear calipers. Make sure that the parking brake lever is
released. Using a screwdriver, push back slightly on the brake pads until
the brake disc is allowed to turn freely on its spindle. Be careful to check
the fluid level in the master cylinder reservoir, as pushing the pads back
will make the fluid level rise and may cause it to overflow.
Once the brake
disc can be moved easily, move to the cockpit of the car, lift up the
handbrake boot, and loosen the two nuts that attach the handbrake cable to
the inside of the brake mechanism (Figure 1 and
Figure 2). If there is any pretension on these
cables, then it will be difficult to adjust the handbrake. The adjustment of
the parking brake shoes is accomplished by turning a small gear or sprocket
with a screwdriver. Unfortunately, this sprocket can only be reached through
one of the lug nut holes in the brake disc.
Rotate the brake
disc until you can see the small adjusting sprocket through the lug nut hole
(Figure 3). You may need a flashlight for this
procedure. Reaching in through the hole, use a screwdriver to rotate the cog
until the parking brake shoe is tight and the rotor can no longer be
rotated. A glimpse of what the cog looks like with the brake rotor removed
is shown in
Figure 4. If you are working on the
right side of the car, you need to turn the cog towards the front of the car
to tighten the brake shoes. If you are working on the left side of the car,
you need to rotate the cog to the rear of the car to expand the shoes. If you are turning the sprocket a lot, and the brake disc
isn’t tightening up, then you are probably turning it the in the wrong
direction. Repeat this procedure for the opposite side of the car. After you
have the sprockets adjusted so that the brake shoes have just pressed up
against the inside of the disc, and you can no longer turn the disc, back
them off until the disc can spin.
Now move back to
the cockpit of the car, and pull up on the hand brake several times to help
seat the cables. Finally, pull up on the hand brake so that the ratchet
clicks through four notches. Now, tighten up the cables using the nuts at
the bottom of the handbrake lever (Figure 5). Tighten
each of these nuts to the point where there is just a bit of slight
resistance each respective wheel. Now, release the lever and verify that the
wheels turn freely. The brake discs should be free to rotate with the handle
in the down position, but fully locked by the time that the handbrake is
pulled up a few notches past the four clicks.
When you are
finished, recheck the master cylinder reservoir, and also step on the brake
pedal a few times in order to make sure that the pistons have repositioned
themselves properly against the brake pads. Also verify that the parking
brake lamp on the dashboard illuminates as soon as the handle is pulled up.
Well, there you have it - it's really not too difficult
at all. If you would like to see more technical articles like this one,
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Palle Bo Madsen adds the
Due to the fact
that everybody only uses the emergency brake as a parking brake, the
brakedrum gets rusty inside, at least in the wet and cold season/climate.
When You then try to adjust or brake it in, the rust becomes a glassy layer
on the inside of the drum and on the brake shoes. This glass like layer has
very little friction, so You can't stop the car with the emergency brake,
but only use it as a parking brake.
Remedy: The BMW workshop changes the disc, the brakeshoes and the brakepads...
I use sanding paper either by a rotating machine or by hand to remove the
rusty and or glass like layer from the inside of the drum and the brake
shoes. Then I put it back together, adjust it with the cogwheel as You have
described it and then run the emergency brake in. Now it is working as it