9940259 R02 - 2022
RZR
PRO R / PRO R 4 Service Manual
© Copyright Polaris Industries Inc.
10.21
9. Measure piston diameter and replace if damaged or
worn beyond service limit.
MEASUREMENT
Front Caliper Piston O.D.:
Small Bores: 1.368 - 1.369″ (34.76 - 34.80 mm)
Large Bore: 1.498 - 1.499″ (38.06 - 38.10 mm)
10. Inspect the brake disc and pads as outlined in this
chapter.
BRAKE PAD INSPECTION
Measure the thickness of the pad material and backing
plate with a caliper. Replace pads if worn beyond the
service limit.
MEASUREMENT
Brake Pad Thickness:
.296 ± .007″(7.53 ± .19 mm)
Service Limit:
.180″ (4.6 mm)
FRONT CALIPER ASSEMBLY
1. Coat piston with clean Polaris DOT 4 Brake Fluid
(PN
2872189)
. Install piston with a twisting motion while
pushing inward. Piston should slide in and out of bore
smoothly with light resistance.
2. Install new sealing o-rings inside the caliper.
3. Carefully press the pistons into the caliper.
4. Install the mount bracket assembly and dust boots.
5. Compress the mounting bracket and make sure the
dust seals are fully seated. Install the brake pads.
Clean the disc and pads with brake parts cleaner or
denatured alcohol to remove any dirt, oil or grease.
BRAKE DISC INSPECTION
1. Visually inspect disc for scoring, scratches and
gouges. Replace disc if deep scratches are evident.
2. Using a micrometer, measure disc thickness at eight
different points around the pad contact surface.
MEASUREMENT
Brake Disc Thickness
.295 ± .008″(7.5 ± .2 mm)
Service Limit:
.268″ (6.8 mm)
Brake Disc Thickness Variance:
Service Limit: 0.002″ (0.051 mm)
3. Mount a dial indicator. Slowly rotate the disc and read
runout on the dial indicator Replace disc if runout
exceeds specifications.
MEASUREMENT
Brake Disc Runout:
.010″ (0.25 mm)
