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Much of the difficulty associated with the
installation of this Mov'it rear brake kit has to do with the small
rotor size (322mm) resulting in the positioning of the Porsche caliper
very close to the hub. This requires
grinding of mounting ears, lower control arm, and knuckle as well as
modification of the parking brake mechanism.
The Brembo and StopTech rear brake kits for
the E39 use much larger rear rotors (345mm and 355mm respectively) and
require no grinding. The installation of Brembo and StopTech rear
kits is only slightly more complicated than changing pads and rotors and
can be done by a reasonably skilled person in about two or three hours.
Do not let these complicated Mov'it instructions scare you away from a
Brembo or StopTech rear kit! StopTech and Brembo brake kit
installation is much easier. |
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The Mov'it rear brake kit for the E39
is one of the more challenging to install. This is not for
the beginner! Plan on an entire weekend to install both
sides.
To retain the parking brake function
inside the rear rotor, some part swapping and machining is done by
Mov'it. The E39 parking brake shoes are too big to fit inside the
tiny Porsche 993 TT rear rotors, so the smaller E38 750iL parking brakes
are supplied.
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Safety Warning:
Working on
your own car can be dangerous. Even quality jack stands can collapse
if not positioned properly, and a floor jack can fail suddenly and without
warning. You can be seriously injured or even killed if you do not
follow proper safety procedures. Please use both a floor jack and a
good pair of jack stands to support your car so that a failure of any single
support is less likely to result in the car falling on top of you!
Zeckhausen Racing LLC assumes no liability expressed or implied for the
improper installation or use of these components.
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Installation Instructions
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Place a floor jack underneath the
differential. Jack stands go under the plastic jacking points
located along the bottom of the frame rails. Lower the car onto
the jack stands allowing most of the weight to rest on the stands, but
leave the floor jack in place as a safety measure. Place chocks
around the front wheel to keep the car from rolling in either direction.
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Remove the rear wheels using a 17mm
6-point socket.
A quality air wrench makes the job go much
faster. I use a powerful, but lightweight and compact air wrench
made by Ingersoll-Rand. It's the Model 2121 Heavy Duty series and
it's a joy to use. Because it is so tiny, I can use it in places
where a normal sized air wrench simply wouldn't fit.
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Shown is the stock 540i rear brake.
Note the backing plate that extends from behind the rotor. We'll
be cutting that plate to make room for the larger rotor and calipers.
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On the passenger side is a wire harness
with a sensor attached to one of the brake pads. When the pad
wears out, a wire is cut and a warning appears on your dash. We
will disable this warning function.
StopTech rear brake kits do not require
these steps, since the pad wear sensor function is retained.
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Pull the sensor wire from the brake pad
with your fingers. If it doesn't pull straight out, try a pair of
needle nose pliers.
Follow the sensor wire back behind the
inner fender liner to where it enters a small plastic holder. Both
brake pad wear sensor and ABS sensor harnesses terminate here.
Disconnect the brake pad wear sensor connector by squeezing the
retaining tabs on the male end and pulling it straight out.
The photo shows the brake pad wear sensor
harness removed, with the male end of the plug remaining behind.
The blue cylinder to the left is the ABS sensor harness connector.
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Cut the harness about 3 inches from the
connector. Strip the wires and twist the bare ends together.
Solder the ends and cover with electrical tape or heat shrink tubing.
Then reattach the connector to the base inside the plastic holder behind
the inner fender liner. Be careful to orient it properly by observing
how the pins line up.
Turn your ignition key to the run position
and verify there are no warning messages about worn brake pads. If you
see a warning, it means you didn't properly connect the harness. Pull
it apart again, double check the alignment, then push it back on and
recheck the dash warning. To reset the warning, you will need to
turn the key to the run position, but do not start the car. After
45 seconds, the warning light should reset.
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Remove the spring steel clip from the
caliper.
An easy method is to squeeze the clip with
a large pair of needle nose pliers. Or you can compress it with a
large screwdriver or a small pry bar. Then use your fingers to
pull the clip forward away from the rotor. It should pop right off.
You don't need to force it.
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Remove the caliper from the frame by using
a 7mm Allen bit to unscrew the two slide pins. The slide pins are
hidden beneath plastic caps which may be pried off with your fingers.
In order to get clearance for your ratchet while removing the lower
caliper slide pin, you may need to jack the suspension up by placing a
floor jack under the knuckle, just behind the rotor.
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Wiggle the caliper until it pulls off the
rotor. The outer pad will remain behind on the frame, while the
inner pad will stay clipped to the caliper. Don't force anything.
It should come off after a bit of wiggling.
Normally, it is not a good idea to dangle
a caliper by the brake line. But in this case, the brake line
fitting screws straight into the lightweight caliper. It is fine
to just let it hang. You won't hurt anything.
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Use a 16mm socket to remove the two bolts
holding the caliper frame.
The lower bolt will be partially
obstructed by the aluminum control arm. It helps if you use a
floor jack to raise the suspension to it's highest point so that the
control arm is nearly parallel to the floor. This gives you easier
access to that lower bolt. Be careful not to lift the car off the
jack stands.
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Use a 6mm Allen bit to remove the rotor
retaining screw. Save this screw since you will reuse it later.
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Check that the parking brake is not
engaged.
Make sure the wheel installation guide
tool you used earlier is still attached so that the rotor doesn't fall
off and land on your foot. Use a dead blow hammer with a rubber or
plastic face and strike the rotor until it becomes loose. You may
need to hit it hard and often if your car is older.
If it still does not come off, go back and
check again to make sure the parking brake is really
disengaged!
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Now you can
see the parking brake assembly. Study it closely so that you
understand how it functions and how the parts go back together.
At this point, you may want to take a
sharp object and use it to scribe a line in the backing plate around the
parking brake shoes. This will give you an approximate idea of where to
cut the backing plate in a later step.
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Remove the upper and lower parking brake
return springs.
You will need brake spring pliers to
remove and reinstall the two springs in the parking brake assembly.
This task is nearly impossible without this tool. Trust me on this
one!
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You will need to use a special BMW parking
brake tool for removing and installing the brake shoe retainer pins.
Use the tool to press down on the
retaining pin, then turn it 1/4 turn in either direction. It
should pop right out and the brake shoe will fall into your hand.
(Or onto the floor, if you weren't ready for it!)
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This photo should help you understand the
proper orientation of all the parts.
The two springs are not the same size.
The larger one goes on top.
The cylinder on the bottom with the raised
teeth is an adjustment device which is turned clockwise or
counterclockwise with a screwdriver tip in order to make it wider or
narrower. This is how you adjust the parking brake.
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Using a 16mm offset wrench, remove the two
bolts shown and pull out the upper support. Also pull out the rubber
gasket that goes around the upper support. Note the orientation of the
gasket. The depression faces out, as shown in the photo. It won't fit
properly if you try to install it backwards in a later step.
You can see the tip of the parking brake
cable directly to the right of the wrench. Push the cable back
into the hole so that it is out of the way for the next step.
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The upper support you just removed will be
replaced with a new one that mov'it has machined to fit within the
Porsche rotor hat. The old piece is shown on the left. The
new one is on the right. (Don't install this yet.)
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This photo shows a summary of the next
phase of the installation. Click on the image for a full-sized photo.
Remember: none of this grinding is required for StopTech or
Brembo kits.
We will trim the metal backing plate with
tin snips, then remove a small amount of material from the aluminum
knuckle and control arm to provide clearance for the caliper, rotor, and
adapter bracket. And finally, we'll grind flat the mounting ears for
the stock caliper so they fit flush with the new caliper adapter
bracket.
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Remove the four 10mm bolts holding the
backing plate to the knuckle. Pull the backing plate forward and rotate
so you may easily cut it with tin snips. The object is to remove enough
material so the backing plate can fit inside
the rotor, but not too much that the parking brake shoes are not
properly supported. You should cut the plate right at the point where
it starts to bend, just slightly inside the score mark you made is an
earlier step. Remember, the E38 750iL parking brakes you will install
in a later step are slightly SMALLER than the 540i parking brakes.
The photo shows the material removed
from the backing plate. This outer piece may be discarded.
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Reattach the backing plate with the
four 10mm bolts. Install the modified support bracket with two 16mm
bolts. Reinstall the rubber gasket.
Test fit the rotor over the hub and
turn it. If there is no interference, you are all set. But
it's possible you will hear a scraping sound when you rotate the rotor.
To help determine where you need to remove more material, put electrical
tape around the edges of the backing plate, then reinstall the rotor and
rotate it. The electrical tape will become worn where there is
interference. Use a course file to remove more material and then
repeat the process until the rotor no longer scrapes the backing plate.
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For the next few steps, you'll need an
angle grinder such as the 4 1/2" Sears model shown here. It will
be used to remove material from the control arm and knuckle.
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Next, we will use the grinder to
remove material from all the locations shown by the red arrows.
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Compress the suspension with a floor
jack, but stop raising it BEFORE the car lifts off the jack stands..
Install the bracket temporarily on the
mounting ears. It will be immediately obvious that the control arm
interferes with the bracket, especially when the suspension is lowered.
Use a laundry marking pen to mark the control arm, then remove the
bracket. Grind off enough material from the control arm so that
the bracket clears it. Now lower the jack and make sure the
bracket still clears the control arm, even when the suspension is fully
lowered.
Caution: Before you grind the
control arm, install the protection hose clamp as described in the next
two steps.
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Right next to the part of the control arm
you are about to grind is a rubber boot. It is very easy to nick this
boot with the angle grinder. You don't want to do this, since taking
that part of the suspension apart in order to install a replacement boot
is not easy. So how do we protect the boot?
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I just happened to have some hose clamps
on my shelf that were the right size. Open the clamp entirely and
thread the metal band around the rubber boot. Then screw it down snug
enough so that the boot is compressed down out of the way and completely
shielded from any careless grinder accidents.
Now you can grind away to your heart's
content.
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Grind off the mounting ears so that
they are just below the level of the caliper mounting surface on the
bracket. You will need to keep placing the bracket on the ears to
check your progress, then remove more material, then repeat until done.
You can't put material back, so be patient and just remove a little bit
at a time.
Once you have removed enough material
from the ears, you will be ready to attach the caliper bracket.
Two different thickness shims were included in the kit to move the
bracket slightly toward the center of the car. At this time, you
should use the thicker shims, placing one between each aluminum ear and
the bracket before installing the nuts. (Warning: the shims
will stick out above the bracket. Use a file to flatten one edge of the
shims so that they are flush with the bracket.)
If you cut a cross section of what you
just installed, you would see the following parts in order: Bolt,
washer, aluminum ear, shim, caliper bracket, washer, nut. Tighten
the nuts just enough to hold the bracket firmly in place. You will
be removing it in a later step, so do not torque all the way at this
time.
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Now it's time to assemble the parking
brake. Extend the end of the parking brake cable with a pair of
needle nosed pliers. (You had pushed it into the hole earlier,
prior to cutting the backing plate.)
Using the new parking brake hardware,
hook the end of the cable into the metal piece. (I haven't a clue
what BMW calls this part!)
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Using the special tool, attach the new
parking brake shoes to what remains of the backing plate by inserting
the spring loaded pins and rotating them 1/4 turn. The pins go
through a hole in the shoe and then through a slot in the backing plate.
If you use a flashlight from behind, it's easier to line up the pins
properly.
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Slip the adjusting wheel into place at
the bottom, between the two shoes. Then, use the brake spring
pliers to reinstall the two springs. Remember, larger spring goes
on top.
Use a small piece of metal or wood
between the friction surface of the parking brake shoe and the sharp
point of the spring pliers in order to avoid damaging the brake shoe.
I've also found a leather work glove works well because it doesn't
slip.
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Slip the rotor over the parking
brake/hub assembly and rotate it. If there are no scraping sounds,
remove the rotor and turn the adjusting wheel with the tip of a
screwdriver a couple turns to push the brake shoes apart. Then
test fit the rotor again. Keep doing this until the shoes just
barely touch the rotor. Then back off by 1/4" turn.
You want to perform these adjustments
with the parking brake lever DOWN!
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The next step is to make sure the
caliper is properly centered about the rotor. Make sure there are
no brake pads mounted in the caliper. Bolt the caliper to the
adapter bracket using the two large allen bolts. You'll need a
10mm allen bit for your ratchet. Tighten the bolts snug enough to
hold the caliper firmly in position but do not torque at this time.
You will disassemble this again later.
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Look into the caliper and observe the
gap on either side of the rotor as shown by the yellow arrows. The
spacing should be the same on either side. If not, the caliper
must be moved out or in. To move it out (away from the center of
the car) you will replace the thick shims with thin ones. To move
it in, you will add shims. Remove caliper and bracket, replace
shims, and try again. Repeat until the caliper is centered about
the rotor. Then remove the caliper and set it aside. Tighten
the nuts on the bracket to 50 lb-ft. Use Loctite thread locking
compound on the bolts.
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Place a pan beneath the caliper to
catch dripping brake fluid.
An open end wrench is used to
stabilize the brake line fitting from below while an 11mm flare wrench
is used to loosen the nut from above. You MUST use a flare wrench
or else you will strip the nut!
Once the nut is loose, unscrew it the
rest of the way with a stubby open end wrench.
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In this photo, I have pulled the hard
line up and out of the bracket and rubber grommet and snapped a rubber
cap on the end to stop brake fluid from leaking out. I highly
recommend that you pick up such a cap at the auto parts store before
removing the brake line. It prevents all the brake fluid from
draining while the line is disconnected.
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There may be a red plastic cap and
rubber washer on the Porsche caliper designed to keep out moisture
during shipping. If so, remove and discard the cap and washer.
Use a 14mm flare wrench to install the
brake line on the Porsche caliper. Tighten firmly. Unlike
the front brakes, there are no crush washers or banjo fittings used.
The brake line screws straight into the caliper.
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Attach the caliper to the mounting
bracket with the two large allen bolts. You will need a 10mm bit
for your ratchet. Tighten firmly. We will torque these bolts
later.
Unsnap the rubber cap from the hard
brake line and place it in the rubber grommet. Run the flexible
brake line through the rubber grommet from below, making sure that you
reuse the original washers on either side of the grommet.
Use your fingers to thread the nut properly into the fitting on the end
of the flexible brake line. Tighten as far as possible with your
fingers, then continue to tighten with a stubby 11mm open end wrench.
At this point, you should stabilize the fitting on the flexible line
with a 17mm flare wrench.
When the 11mm open end wrench becomes
hard to turn, finish tightening the nut with an 11mm flare wrench.
Wipe all surfaces dry with a paper
towel.
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Open the pad retainer by squeezing the
center together with pliers while pulling up on the end to free it from
the lip that holds it down.
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Insert new brake pads. They
should slide right in.
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When you insert both pads, they should
align fairly closely to the curvature of the rotor as shown here.
Close the pad retainer by squeezing it
in the center, as before, with a pair of pliers while pushing the end
under the lip to hold it in place. This is easier to do if someone
else pushes on the retainer while you squeeze the pliers, but it can be
done by one person.
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Torque the two caliper bolts to 60
Lb-ft. It's a good idea to put a small amount of blue Loctite on
the bolts.
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Bleeding the brakes comes next.
Shown is a pressure bleeder with an adjustable pressure regulator and a
built-in pressure gauge. It's possible to do this without the
pressure bleeder, but this makes it easier to get a good bleed.
The brake fluid reservoir is hidden
beneath the driver's side microfilter housing. Make sure the
reservoir is filled to the top. Connect the pressure bleeder to
the reservoir, attach compressed air fitting, and adjust to about 20
psi.
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Place an 11mm 6-point box end wrench
over the outer bleed screw. Attach the hose from the brake fluid
catch bottle to the nipple on the end of the bleeder screw and crack
open the screw about 1/4 turn. If you are using the pressure
bleeder, leave the screw open until the large air bubbles stop coming
out and mostly fluid is visible through the clear hose. Tighten
bleeder screw and repeat process on the inner bleed screw.
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Have your assistant sit in the
driver's seat and press the brake pedal on your command. After the
brake pedal is depressed, open the bleeder screw quickly and then close
it before the brake pedal sinks all the way to the floor. Repeat
this a few times until there are no longer ANY air bubbles visible in
the clear plastic hose.
It is important to check the level of
brake fluid in the reservoir and add more as necessary. You do not
want to get any air into the master cylinder. Check around the
brake line fittings for any leaks before declaring success and
reinstalling the wheels. Torque wheel bolts to 88 Lb-ft.
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You may click on the next
3 images
to see full sized photos
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On your first test drive, brake normally
and listen for any unusual noises. A slight scraping sound when
you apply the brakes is normal for the first few miles until the pads
and rotors bed in properly. After you have convinced yourself that
everything is OK, follow my
brake bedding instructions.
Now, step back and admire your work.
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Pedal feel should be improved over the
front-only installation with just a fraction of an inch of pedal travel
before braking begins to occur.
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