Front Brake Pad Replacement - Polaris 1999 Sportsman 400 Service Manual

BRAKES
wor k environment when any service is being per-
formed , Any tiny particl e of debris that enters the
system can dam age the components and ca use poor
brake performance.
Brake fluid is hygroscopi c (easily absorbs mo is-
ture) and moisture in the sys tem will reduce brake
per fonnancc.
It
is a good idea to purc hase brake
fluid in small con tainers and disca rd any sma ll
quantities that remain. Small quantities of tluid will
qu ickly absor b the moi sture in the container. Usc
onl y fluid clearly marked DOT 3. If possible, usc
the
same brand of fl uid,
Do not replace the fluid
with DOT 5 (sil icone) fluid,
It
is not pos sibl e to re-
move all of the old fluid and DOT 5 is not compati-
ble with other types. Silicone type fluid s used in
systems for which thcy were not designed will
cause internal seals to swell and deterio rate. Do not
reuse drain ed fluid and disca rd old fluid properly.
Proper service a lso includes ca refully pcrfonned
procedure s. Do not use any sharp too ls inside the
master cylinders or cal ipers or on the pistons. Any
dam age to these co mpo nents could cause a loss in
the systems ability to maintain hydraulic pressure.
If the re is any doubt about having the ability to cor -
rectly and safely service the bra ke system. ha ve a
profession technician perform the task .
Consider the followin g whe n servicing the brak e
system:
I. The hydrau lic components rarel y require disas-
sembly. Make sure it is neces sary.
2. Keep the
reservoir co vers in place to prev ent the
ent ry of moisture and debri s.
3. Clean parts with an aerosol brake parts cleaner
or isopropyl alcohol. Never use petroleum based
solvents on internal brake system com ponents.
They will cause seals to swe ll and distort.
4. Do not allow brake Iluid to co ntact plastic,
painted or plated part s. It will damage the surface.
5. Dispose of brake fl uid propcrly.
6. If the hydrau lic system has bee n ope ned (not in-
cluding the rese rvoir co ver) the system must be bled
to remove air from the system. Refer to Bleeding the
System
in this chapter.
WARNING
Whenever workin g on the brake sys-
tem, do n ot inhale brake du st . It ma }'
contain asb estos, which can cause
lung injury and cancel: fJ"ear a
facemask that meets OSHA require-
ments for trapping asbestos particles,
383
ami wash both hands and fo rearms
thoroughly after comp leting the work.
WAR NING
N E VE R use comp ressed air to clean
any paris of the hrake system as this
will release the harmful brake pad
dust. Use an aerosol bra ke cleane r
/0
clean parts when servicing allY com-
ponent still
ills
tailed
0 11
the
vehicle .
FRONT BRAKE PAD R EPLAC EM ENT
There is no recommended interv al for changing
the brake pads. Pad wear depends greatly on riding
conditio ns. Check the pads for wear prior to each
ride or when thc brake pads wear clo se to the edge
of the brake disc. Measure the thickness of each
brake pad w ith a vernier caliper or ruler and com-
pare it to the dimension s listed in Ta ble I.
Rep lace bot h brak e pads in both calipers at the
same time . Do not disco nnect the hydrau lic brake
hose from the bra ke ca liper for brake pad repla ce-
ment, disco nnect the hose on ly if the caliper assem-
bly is go ing to be removed.
Refer to Figure I.
I. Remove the front whee ls as described in Cha pter
Eleven,
2. Unscrew and remove the pad adjust screw (F ig-
ure 2).
NO TE
Only one boll is sh own in Figure 3,
relllO"e
both bolts.
3. Remove both bo lts and was hers (F igure 3) se-
cur ing the brake ca liper mounti ng and remove the
L ; = ; " ' :
ca liper from the bra ke disc.
4. When reposition ing the brake pads in the caliper,
the master cy linder brake !luid level will rise as the
ca liper piston is repos itioned. Perform the follow ing:
a. Clean the top of the master cylin de r of all de-
bris.
b. Place a plastic drop cloth over the front fender
and fuel tank.
c. Remove the top cov er. screw s. cover (Figu re
4) and diaphra gm from the master cylinder.
WAR NING
Brak e fluid is
poisonous;
do
1101
si-
phon it by
mouth .