PREVOST H3-41 Maintenance Manual page 439

FIGURE 32: PUSH CALIPER THREE TIMES IN AXIAL
DIRECTION
6. Push and pull caliper three times in axial
direction to assess any existing air gap
(see Figure 31. If no movement is possi-
ble, clean the disc brake and if necessary,
replace the bearings. Once movement is
obtained, continue as follows:
7. Pull off the adjuster cap (37) using the tag,
taking care not to lose the shear adapter
(61) (see Figure 32).
Removal of the adjuster cap (37) with a
screwdriver, or similar, is not allowed since the
seal may be damaged.
FIGURE 33: REMOVE CAP, INSERT NEW BRAKE PADS,
SET THE STARTING GAP
8. Insert new brake pads).
9. Set the starting gap by turning the adjuster
(23) with the shear adapter (61) back-
wards and then forwards (note that when
turning backwards a noticeable clicking
can be heard and felt), until a value of
0.051 in (1.3 mm) air gap has been
achieved (measure between the brake
pad and tappets (13).
10. Apply the brakes 20x with medium
pressure.
SECTION 12: BRAKE AND AIR SYSTEM
11. Check the gap between each of the
tappets (13) and inboard pad backplate
(12). This must be measured over the
whole tappet surface of both tappets using
two feeler gages simultaneously (feeler
gages must be at least 8 ½ in / 220 mm
long) (see Figure 33).
12. If the gap difference between the two
tappets is > 0.009 in / 0.25 mm then the
caliper
checked (see 18.2.7 Checking Caliper
Running Clearance & Checking Caliper
Movement Along Guide Pins).
13. In addition, each gap must measure
between 0.023 - 0.047 in (0.6 - 1.2 mm).
If the clearance is too great, there is a danger of
brake failure. If the clearance is too small, there
is a danger of overheating that may lead to
consequential damage.
FIGURE 34: CHECK GAP BETWEEN TAPPETS AND
INBOARD PAD
If the air gap is larger than 0.047 in / 1.2 mm,
the adjuster must be checked as follows:
14. Turn the adjuster with adapter (61) 3
clicks anticlockwise (increasing the air
gap) (see Figure 34).
Make sure the ring spanner or socket can turn
freely clockwise during the following procedure.
PA1621 Maintenance Manual All Series | Revised June 2020
bearing clearance must be
35