|
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. |
|
|
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.
|
|
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.
|
|
Installation Instructions
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
Use a 6mm Allen bit to remove the rotor
retaining screw. Save this screw since you will reuse it later.
|
|
|
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!
|
|
|
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.
|
|
|
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!
|
|
|
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!)
|
|
|
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.
|
|
|
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.
|
|
|
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.)
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
Next, we will use the grinder to remove
material from all the locations shown by the red arrows.
|
|
|
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.
|
|
|
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?
|
|
|
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.
|
|
|
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.
|
|
|
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!)
|
|
|
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.
|
|
|
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.
|
|
|
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!
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
Insert new brake pads. They should
slide right in.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
You may click on the next 3 images
to see full sized photos
|
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.
|
|
|
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.
|
|
|
|
|
