Polaris 1999 Sportsman 400 Service Manual page 402

396
Ins pection
CA UTION
Never lise pe troleum-based sol vents
0/ allY kind un internal brake sys tem
components. Any residual sol vent will
cause the new seals to swell lind dis-
tort and requ ire repla cement.
I.
Clean the ca liper body and piston in de natured
alco ho l or fresh DOT 3 brak e tl uid. Wear eye pro-
tect ion and blow dry with compresse d air directing
the air flow and resid ual fluid away
trom
you.
2. Make sure the fluid passagewa y in the base of
the pisto n bore is clear. App ly compressed air to
make sure it is clear.
3. Inspect the dust and piston seal grooves in the
ca liper body for da mage. If they are damaged or
corroded, rep lace the caliper assembly.
4. Inspect the brake hose inlet filling in the bac k-
side oft he ca liper body. If worn or damaged, clean
out with a thread tap or rep lace the ca liper asse mb ly.
5. Inspect the bleed screw threaded hole in the cali-
per body . If worn or dam aged, clean out with a
thread tap or replace the ca liper assembly.
6. Inspect the bleed screw, Make sure it is clean and
open.
Apply
compre ssed air to the ope ning and
make sure it is clear. Clean out if
necessary
with
fresh brake tluid . Install the bleed serew and tighten
secure ly.
7. Inspect the pad retaining pins (Figure 30) for ex-
cessive wear, da mage or uneven wear. The pins
must be clean and in good condi tion for proper
brak e operation.
8. Inspect the caliper body for da mage; replace the
cal iper body if necessary.
9. Inspect the caliper piston bore for cracks, deep
scoring, or exces sive wear.
10. Check the ca liper piston for scratches, scoring
or rust.
11. Meas ure the inside diameter of the piston bore
with
a
snap gauge or verni er caliper. Rep lace the
cali per
if the
bore dia meter is less than the servic e
lim it dimension listed in Table 1.
12. Measure the outs ide diameter of the piston with
a micrometer or vernier ca liper. Rep lace the piston
i f the diameter is worn to less tha n the serv ice limit
d imension listed
in Tahle I.
13. The piston seals help
to
maintain corr ect brake
pad to disc clearance. If the seals arc worn or dam-
aged. the bra ke pads will drag and cause exc essive
CHAPTER FOU RTEEN
wea r and increas e bra ke lluid temp eratu re. Replace
the piston sea ls and dust seals if the followin g con -
d itions ex ist:
a. Brake Iluid leaks a round the inbo ard brake
pad .
b. Piston sea l is stuck.
c. There is a large difference in the inner and
outer brak e
pad
thickness.
NOTE
Never rellse an old dust or piston seal.
l e I} '
minor damage or age deteriora-
tton con mak e the seals useless.
14. Inspect the brake pads (Figu re 3 1) for uneven
wear, damage or grease contamination . If the pad
thickne ss is within speci fication. clean off the pad
surface with an aero sol brak e clean er to remove any
surface contam ination.