Overhaul - Yamaha TDM850 User Manual

slide the caliper off the disc (see illustrations).
4 If the calipers are being overhauled, remove
the brake pads (see Section 2). If the calipers
are just being displaced, the pads can be left
in place.

Overhaul

5 Clean the exterior of the caliper with brake
system cleaner or denatured alcohol. On XTZ
models, if not already done, separate the caliper
bracket from the caliper, noting how it fits (see
illustration 2.2e).
6 Displace the pistons as far as possible from
the caliper body, either by pumping them out by
operating the front brake lever or rear brake
pedal (as applicable), or by forcing them out
using compressed air. If the compressed air
method is used, place a wad of rag between the
pistons and the caliper to act as a cushion, then
use compressed air directed into the fluid inlet to
force the pistons out of the body. Use only low
pressure to ease the pistons out and make sure
the pistons are displaced at the same time. If the
air pressure is too high and the pistons are
forced out, the caliper and/or pistons may be
damaged. On opposed piston calipers there is
not enough room to remove the pistons from both
sides at the same time, so block one side in their
3.7 Use a plastic or wooden tool (such as a
pencil) to remove the seals
bores using a piece of wood and displace the
opposite side first, then remove the seals (see
below), reinstall the removed pistons and block
them using the wood while removing the other
side. Now remove the wood and the first pistons,
which can now be easily removed. Mark each
piston head and caliper body with a felt marker to
ensure that the pistons can be matched to their
original bores on reassembly.
A
Warning: Never place your fingers
in front of the pistons in an attempt to
catch or protect them when applying
compressed air, as serious injury
could result.
Caution: On TDM and TRX models, do not
attempt to remove the caliper body bolts and
separate the caliper halves.
7 Using a wooden or plastic tool, remove the
dust seals from the caliper
illustration). Discard them as new ones must be
used on installation. If a metal tool is being used,
take great care not to damage the caliper bores.
8 Remove and discard the piston seals in the
same way.
9 Clean the pistons and bores with clean brake
fluid. If compressed air is available, use it to dry
the parts thoroughly (make sure it's filtered and
unlubricated).
3.16 Tighten the caliper mounting bolts to the
specified torque
Brakes, wheels and tyres 7*7
Caution: Do not, under any circumstances,
use a petroleum-based solvent to clean brake
parts.
10 Inspect the caliper bores and pistons for
signs of corrosion, nicks and burrs and loss of
plating. If surface defects are present, the caliper
assembly must be renewed. If the caliper is in
bad shape the master cylinder should also be
checked.
11 Lubricate the new piston seals with clean
brake fluid and install them in their grooves in the
caliper bores. Note that on some models different
sizes of bore and piston are used (see
Specifications), and care must therefore be taken
to ensure that the correct size seals are fitted to
the correct bores. The same applies when fitting
the new dust seals and pistons.
12 Lubricate the new dust seals with clean
bores (see
brake fluid and install them in their grooves in the
caliper bores.
13 Lubricate the pistons with clean brake fluid
and install them closed-end first into the caliper
bores. Using your thumbs, push the pistons all
the way in, making sure they enter the bore
squarely.
Installation
14 Install the brake pads (see Section 2).
15 Install the caliper on the brake disc making
sure the pads sit squarely either side of the disc
(see illustration 3.3b).
16 Install the caliper mounting bolts, and tighten
them to the torque setting specified at the
beginning of the Chapter (see illustration). On
XTZ models, if the pads were removed, now
tighten the pad retaining pins to the specified
torque (see illustration 2.2a).
17 If removed, connect the brake hose to the caliper,
using new sealing washers on each
fittings (see illustration 7.4). Align the hose as noted
on removal (see illustration 3.2a). Tighten the banjo
bolt to the torque setting specified at the beginning of
the Chapter. On the rear caliper on TDM models, fit
the hose against the hose joint and tighten the locknut
onto the hose, counter-
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side of the banjo
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