Clearance Measurement Check Of Bearing Variants (6); Checking Sealing Elements - Caliper Guide Pin Seals - PREVOST H3-41 Maintenance Manual

SECTION 12: BRAKE AND AIR SYSTEM
FIGURE 42: FREE MOVEMENT OF CALIPER > 0.984 IN /
25 MM
18.2.9 Clearance Measurement
Bearing Variants (6)
Note: Before commencing (removing the wheel),
make sure there is no contact between caliper
and axle, vehicle, chassis sections or carrier. In
such cases, it will be necessary to replace the
caliper bearings (see Knorr-Bremse Pneumatic
Disc Brake Y006471 Service Manual.).
To measure the clearance, the following steps
must be taken:
1. Remove the wheel.
2. Remove pad retainer.
To achieve the correct reading it is necessary to
have a pair of new brake pads fitted. If the
clearance measuring is not taking place during a
brake pad replacement, the current position of
the assembled pads must be noted before
removing, so that they can be re-assembled in
the same position.
Remove old pads and replace with a pair of new
pads.
3. Fasten a magnetic dial-gage holder to the
carrier (2) on the floating bearing side of
the caliper (1). Use the casting tag on the
caliper (1) as the measuring point - see
arrows A (see Figure 43).
4. Set the dial gage to zero.
5. Place a suitable tool (e.g. screwdriver with
at least 200 mm in length) in a central
position between carrier (2) and caliper (1)
and lever them in opposite directions (us-
ing normal hand-force).
6. Read the maximum value of the bearing
clearance on the dial gage and compare
with the values in the table (see Table).
38 PA1621 Maintenance Manual All Series | Revised June 2020
If the clearance exceeds the given tolerance, the
complete bearing will need replacing using the
relative service kit.
If the clearance measuring is not taking place
during a brake pad replacement, the new pads
should be removed and the previously marked
brake pads fitted in their original positions,
otherwise renew the brake pads as an axle set
and adjust the air gap (refer to Knorr-Bremse
Pneumatic
Manual).
7.
Check of
FIGURE 43: OBTAINING MAXIMUM VALUE OF BEARING
CLEARANCE
18.2.10 Checking Sealing Elements – Caliper
The guide pin (5a or 5b) (as fitted to the fixed
bearing side) is sealed with cover (10a or 10b)
and inner boot (9a or 9b).
Disc Brake Y006471 Service
Fit the wheels. After replacing the wheel
check that it runs interference free.
Guide Pin Seals