This article was first published in 2004.
Last week we inspected the brake system and found a need for new front discs
and pads. The rears were fine but we decided to also do them as well. The new discs are slotted RDAs and the pads,
EBC ‘blacks’ – the street level pads.
The car is a Toyota but much the same applies in
any late model small car.
Here are the new RDA discs. As you can see, they’re slotted – a process that
adds AUD$20 to the cost of each disc. Slots aid in (very slightly) reducing disc
mass but their main benefit is in increased brake bite (the pads are swept clean
each rotation) and better out-gassing (there are paths for the gases to escape
that would otherwise remain trapped between the pad and the disc). Oh yes, and
there’s another advantage - appearance...
The new pads can be seen here. The small pads are for the rear discs and the
larger pads are for the fronts. (Front brakes are always sized larger that rear
brakes because when the car is decelerating, there is a forward weight transfer
so the front brakes can do more braking without locking the wheels. IOTW, the
front brakes work harder, so they’re bigger.) These EBC pads are a Kevlar
The new fluid is Castrol Response, a premium brake fluid that’s widely
Fitting the Front Brakes
Fitting discs and pads is pretty straightforward on most modern cars.
However, remember that you are dealing with an area very important to safety so it’s always best to have a
workshop manual available – even just a basic Gregorys or Haynes style of book.
The first step is to undo the bolts holding the caliper in place.
The caliper can then be removed from the disc.
The caliper, which is still connected to the body via the brakeline, is then
lifted above the disc and hung from a piece of wire. Never suspend the caliper
from just the brake hose.
The discs can then be removed. This type of disc is held in place by the
wheel lug nuts, so once these are undone, the disc can be pulled straight off.
However, over the years discs tend to weld themselves in place. The factory is
aware of this problem so they provide threaded holes in the discs through which
bolts can be inserted so that...
... as you tighten the bolts, the disc gets forced off.
Once loosened in this way, the disc can be pulled off by hand.
The new disc is a direct replacement for the old, but before putting it on
the hub, make sure that the hub is clean of rust or corrosion. A wire brush is
being used here.
The new disc must be cleaned of
its protective oils before being put into service. Wax and grease remover makes a good cleaner...
...to make sure that the disc is free of any contaminant.
The disc can then be placed over the hub before...
...a couple of wheel nuts are used to lock the disc temporarily in place. This
is a good move as it will quickly show you if you have any problems – eg if the
disc fouls the caliper or (later in the process) the pads.
While the front caliper is off, it’s a good idea to push the brake piston(s)
back as far as possible into the cylinders. One way to do this is with a
G-clamp, applying one arm of the clamp to one of the (old!) pads and the other
arm to the other end of the caliper. This creates room for the much thicker new
pads that you’ll be putting into place.
With this caliper design, pad replacement requires bolting the caliper back into
place and then removing just the 'bridge' part. So here is the
caliper – complete with old pads – being bolted back over the new disc.
Two bolts are undone and then...
...the bridge part of the caliper can be pulled off, revealing...
...the pads and their retaining springs.
The old pads can be pulled out but before the new pads are put in, the
anti-squeal shims should be swapped over after being lightly lubricated with
disc brake grease or anti-seize copper grease.
Put the new pads in place and add their clipped-in springs and it’s time for
...caliper bridge to be placed back over the assembly.
With the retaining bolts done up and all bolts checked for tightness, the
front disc-and-pads upgrade is done.
So that the hubs don’t go all rusty and ruin the appearance through your
alloy wheels, spray some paint over the inner part of the discs. You needn’t
worry about masking-off the face of the discs – once being driven, the overspray
will soon be removed by the friction of the pads.
Direction of Slots?
Slotted discs are directional – that is, they have a left-side fitment and a
right-side fitment. Brembo state their slotted discs “should be installed such
that the end of the slot nearest the outer edge of the disc contacts the pad
Doing the rear brakes involves much the same process... but with some
significant differences. This caliper design allows the brake pads to be removed
before the caliper is unbolted. So after removing the pad spring clips...
..and placing them in a marked container (you wouldn’t believe how easy it is
to lose these little beasties)...
...the pad retaining pins can be pulled out...
...and then the pads removed.
The caliper retaining bolts can then be undone before...
..the caliper is removed and hung from a piece of wire.
The disc may then just pull off (or need the persuasion of a rubber mallet or
the screw-in bolts trick shown with the front brakes). Here it just pulled off.
Again the hub should be thoroughly cleaned with a wire brush before...
...the new disc is also cleaned with a solvent.
The new disc can then be placed over the hub.
The caliper can be bolted back into place over the new disc and the...
...lubricated anti-squeal plates swapped over to the new pads. Note that in
this case the new and old pads were of much the same thickness so the piston
didn’t need to be forced back into its cylinder.
The pins and clips were then placed back into the caliper.
Next week – changing the fluid,
bleeding the brakes and then bedding them in.