this tech article I will go over the steps for rebuilding the E36 front
The first step is
Jack up the front end of the car, put it on jack stands and remove the
wheels. Use Wayneís tech article on jacking up the front of the E36 for
Before we actually
take the calipers off, I recommend spraying the whole assembly with a good
quality brake cleaner. This will make the job a bit easier and you wont have
to worry about crud and grime getting in places where wrenches and sockets
will be going. Whenever I am doing brake jobs or anything that will be
dirty, I usually head down to the local self-serve car wash, pop off the
tires, get a can of brake cleaner and spray everything. Then I simply steam
clean it all off.
Once clean, this is how
you do it.
the hood and locate the brake fluid reservoir. Take the cap off and place a
piece of plastic over the top, use something like saran wrap or cellophane.
When you put the cap back on, this will help to create a vacuum and keep the
brake fluid from draining out of the lines.
next step is to disconnect the brake pad sensor wire from the connector.
(Note: the brake pad wear sensor is only on the driverís side, disregard
this step on the passenger side) You will now want to loosen the brake line
where it threads into the caliper. Iíd use a good penetrant spray to
prevent stripping or seizing. Use an open-end wrench to loosen the fitting
and then snug it back up. Loosening this fitting now will make removing the
brake line much easier later on.
look at the caliper spring clip on the outside of the caliper. This is the
brake pad retaining clip. Remove it by carefully prying it off with a
look at the back of the caliper, you will notice two plastic inserts inside
of two rubber grommets. Use a screwdriver to pry the plastic inserts out of
the rubber grommets. Directly behind the inserts are two 7mm Allen head
bolts. These are the caliper guide bolts. Use a 7mm Allen key and remove
these two bolts.
remove the caliper from the rotor assembly, it will simply pull off. Remove
the brake pads as well. One brake pad will be pressed into the caliper
piston. Simply pull the pad out of the piston.
now need to remove the brake line from the caliper. Simply loosen the
fitting and pull the brake line out of the caliper. You will need to plug
the end of the brake line to keep brake fluid from leaking out as well and
keeping dirt and grime from getting into the line. A good way of doing this
is to place a small plastic baggie over the end of the line and use a zip
tie to hold it tight. Itís also a good idea to have a drip tray or oil pan
under the caliper at this time to catch any leaking fluid. Remember, brake
fluid will eat paint, so take care not to get it anywhere near the vehicle.
With that the
calipers removed from the vehicle, we can now begin to rebuild them. The
first step is to push the pistons out of the caliper. Place a block of wood
about Ĺ inch thick between the caliper piston and the outer mounting
flange. Now insert an air nozzle in the hole where the brake line goes and
using low-pressure compressed air, blow the piston out of the caliper. (Use
caution here as the piston will pop out of the caliper with a lot of force,
the wood in there acts as a cushion for the piston) Also, be prepared for a
lot of brake fluid all over the place, so make sure you dressed in your best
Now, take a clean
pan or tray and fill it with fresh brake fluid. Take the caliper piston and
clean it in the fresh fluid. Use a Scotchbrite pad to clean off any dirt or
grime. Now look at the outer face of the piston and look for any corrosion
or pitting in the face. If you find either of these, the entire caliper must
be replaced. You cannot buy the caliper pistons separately. You probably
would want to replace the calipers even if you could get just the piston. A
pitted or corroded piston means that there will be corrosion and pitting on
the inside of the caliper. This is something you cannot fix.
Next, remove the
outer dust cover on the caliper (it will probably come off when you blow the
housing) as well as the inner rubber O-ring that sits in a groove on the
inside of the caliper piston bore. Just use a small screwdriver to catch the
lip of the O-ring, and then carefully work it out of the bore. Take care not
to scratch or gouge the bore with the screwdriver. If you do, the caliper
will be shot and youíll need a new one.
the seals off, clean the caliper. I would start with the outside. Once
again, use a good brake cleaner, a Scotchbrite pad and an old toothbrush. It
isnít really necessary to clean the outside, however in my opinion, you
might as well as long as itís out. What is critical is cleaning the inside
of the caliper. Use the brake cleaner and toothbrush to get inside the bore,
and clean everything get that thing looking like new. Once clean, let the
caliper and piston air-dry.
dry, you can paint the calipers if you like. Pelican sells a kit to do this.
(Please insert link for brake paint here)
Now you will need a
brake caliper rebuild kit, (available from Pelican of course). This kit will
contain two pieces, the inner O-ring for the piston bore and also the outer
Take the inner
O-ring and coat it with either brake fluid or caliper rebuild grease,
available at any auto parts store. This grease is specifically for
rebuilding calipers. Also coat the groove inside the caliper with the
grease. Once coated, press the inner O-ring into the groove on the inside of
the caliper with your fingers.
Next, coat the
outside of the piston with either brake fluid or caliper grease. Now pull
the dust cover over the inside edge of the caliper, with the lip of the dust
cover (the lip that goes in the caliper, not the piston) facing away from
the piston. The edge of the dust cover that will eventually be seated in the
groove on the piston should be facing the piston groove, and the rest of the
dust cover should be hanging slightly over the edge of the piston. While
holding the piston near the caliper housing, push the lip of the dust cover
into its groove in the caliper. Then gently push the piston into the
caliper. The piston will hit the inner O-ring and become more difficult to
press in. Keeping the piston exactly straight, gently tap it into place
using a hammer against a flat piece of metal or wood held against the
piston. You can also insert the handle end of a small hammer into the piston
and then push the piston into the caliper.
Now with the
caliper re-assembled, you can now re-mount it on the rotor assembly.
Re-attach the brake line (donít tighten it yet, just get it snug), insert
the brake pads into the caliper, and install the caliper on the rotor
assembly. Re-install the caliper guide bolts and torque them to 24 ft/lbs.
Now push the plastic inserts back into the rubber grommets, and place the
brake pad retaining clip back on the caliper. Now tighten the brake line. On
the driverís side, re-connect the brake wear indicator sensor.
we are ready to bleed the calipers. In this instance, we will assume that
you have a helper to do this. First, loosen the bleeder screw on the
caliper, then quickly snug it back up, we want to just get it loose, not
remove it. Next, get a jar and fill it about halfway with fresh brake fluid.
Place one end of a clear plastic hose over the bleeder screw and run the
other end into the jar.
open the reservoir cap, remove the cellophane and check the fluid level. Top
it up as needed. Leave the cap off, as this will help to draw fluid through
the system. Have your helper pump the brakes until pressure begins to build
up. Then have your helper step on the brakes to hold the pressure and open
the bleeder valve for about 1 second then quickly close again. You will see
fluid flow through the hose with a lot of air bubbles in it. Having the hose
in a jar of brake fluid prevents air from flowing back into the caliper.
Again, have the
helper again build up pressure on the brakes and hold the pedal down. Open
the bleeder valve for about 1 second then quickly close. You will want to
repeat this step until there are no more bubbles flowing through the line.
As the air is bled from the lines, it will take less time for the
brakes to build up pressure. Check the fluid level in the reservoir while
your helper is pumping the brakes to build up pressure. Do not let the
reservoir run dry or you will have to bleed all over again.
the lines are bled, clean up the area around the caliper. Use the brake
cleaner to get rid of any extra fluid around the area. Once clean, remount
the wheels and lower the car.
Well, there you have it - it's
really not too difficult at all. If you would like
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