SMB-165 – Adjuster Check – New Flyer Xcelsior

SEOCONTENT-START
SMB-165 1 of 4
SERVICE MANUAL BULLETIN
This Service Manual Bulletin is prepared by the Publications Department of New Flyer Industries
Canada ULC. Refer to details below.
The New Flyer vehicles described in this manual may be protected by one or more
patents and design applications or registrations in the United States and Canada,
and in other countries. Refer to “Vehicle Patent Information” in this manual.
Copyright © 2016 New Flyer Industries Canada ULC
ISSUE DATE: Dec 09 2016
SMB-165
APPLICABILITY
VEHICLE LENGTH  30ft.  35ft.  40ft.  60ft.  ALL
VEHICLE TYPE
 Xcelsior®  MiDi®  Invero®
 ALL
 Low Floor  High Floor
FUEL TYPE
 Diesel  Diesel/Electric  CNG  LNG
 ALL
 Fuel Cell  Trolley/Electric  Battery/Electric
SUBJECT Adjuster Check
SECTION TITLE 1 – FRONT AXLE & SUSPENSION
2 – REAR AXLE & SUSPENSION
DETAILS This bulletin provides a minor clarification to the adjuster check procedure
for the Knorr-Bremse SN7000 caliper used on the MAN front & rear
axles.
2 of 4 SMB-165
SERVICE MANUAL BULLETIN
SMB-165
The New Flyer vehicles described in this manual may be protected by one or more
patents and design applications or registrations in the United States and Canada,
and in other countries. Refer to “Vehicle Patent Information” in this manual.
Copyright © 2016 New Flyer Industries Canada ULC
1. Adjuster Check
1. Before starting work, ensure that the
wheels are chocked and the vehicle cannot
roll away.
2. Ensure that service brake and parking
brake are in the released condition.
3. Check the supply pressure of the brake
system. Connect an additional external
supply to prevent pressure drop.
4. Check the brake disc temperature; it
should be between 14°F and 122°F (-10°C
and 50°C).
5. Push and pull caliper three times in the
axial direction to assess any existing air
gap. If no movement is possible, clean the
disc brake and if necessary, replace the
caliper guide pins. Refer to Section 1 & 2
of your New Flyer Service Manual for rpocedure.
Once movement is obtained, continue
to step 8.
Removal of the adjuster cap with a
screwdriver, or similar tool, is not
allowed. Damage to the seal may result.
6. Pull off the adjuster cap using the tag, taking
care not to lose the shear adapter.
Ensure that the brake chamber (service
and parking/emergency) is not exerting
any pressure on the brake caliper during
this test.
7. Push the brake caliper towards the middle
of the vehicle.
8. Push brake lining away from tappets.
9. Check the gap between each of the whole
tappet surface of both tappets using two
feeler gauges simultaneously (feeler
gauges must be at least 200 mm long).
Each gap must measure between 0.028 to
0.047″ (0.7 to 1.2 mm). If the clearance
deviates from the specified value, reset
and recheck the clearance with new brake
pads by proceeding to step 10.
10.Insert new brake pads. Refer to Section 1
& 2 of your New Flyer Service Manual for
procedure.
11.Set the starting gap by turning the adjuster
with the shear adapter backwards and
then forwards until a value of 1.3 mm air
gap has been achieved (measure between
the brake pad and Tappets).
☞NOTE:
When turning backwards a noticeable
clicking can be heard and felt.
12.Apply the brakes 20 times with medium
pressure (approximately 30 to 40 psi (2 to
3 bar).
13.Check the gap between each of the tappets
and inboard pad backplate. Each gap
must measure between 0.028 to 0.047″
(0.7 to 1.2 mm).
This must be measured over the whole
tappet surface of both tappets using two
feeler gauges simultaneously (feeler
gauges must be at least 220 mm long).
See “Fig. 1: Measuring Tappet To Brake
Pad Gap” on page 3.
a. If the air gap is larger than 1.2 mm, proceed
to step 14.
b. If the air gap is smaller than 6 mm, proceed
to step 17.
Additionaly, if the gap difference between
the two tappets is greater than 0.25 mm
then the caliper guide pin clearance must
be checked. Refer to Section 1 & 2 of your
New Flyer Service Manual for procedure. If
the caliper guide pin play is within specification,
then the tappets have lost synchronization
and the caliper needs to be
replaced.
SMB-165 3 of 4
SERVICE MANUAL BULLETIN
SMB-165
The New Flyer vehicles described in this manual may be protected by one or more
patents and design applications or registrations in the United States and Canada,
and in other countries. Refer to “Vehicle Patent Information” in this manual.
Copyright © 2016 New Flyer Industries Canada ULC
14.If the air gap is larger than 1.2 mm the
adjuster must be checked as follows:
a. Turn the adjuster with adapter 3 clicks
counter-clockwise (increasing the air
gap).
Make sure the wrench or socket can
turn freely clockwise during the following
procedure.
b. As a visual aid, position a wrench or
socket onto the adjuster (including
Adapter. Apply the brake 5 to 10 times
(approximately 30 psi (2 bar)), the
wrench or socket should turn clockwise
(viewed from actuator side) in small
increments if the adapter is functioning
correctly. See “Fig. 2: Checking
Adjuster Movement” on page 3.
c. As the number of applications
increases, incremental movement of
the wrench or socket will decrease. If
the wrench or socket does not turn or
turns only with the first application or
turns forward and backward with every
application, the automatic adjuster has
failed and the caliper must be replaced.
15.Lightly grease the contact surface of the
adjuster cap with white grease.
☞NOTE:
A new adjuster cap should be fitted even if
the brake pads are not being replaced.
Fig. 1: Measuring Tappet To Brake Pad Gap
Fig. 2: Checking Adjuster Movement
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s122284a.svg
DETAIL A
ROTATION
ADJUSTER
ADAPTER
10MM
WRENCH
A
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4 of 4 SMB-165
SERVICE MANUAL BULLETIN
SMB-165
The New Flyer vehicles described in this manual may be protected by one or more
patents and design applications or registrations in the United States and Canada,
and in other countries. Refer to “Vehicle Patent Information” in this manual.
Copyright © 2016 New Flyer Industries Canada ULC
16.The tag of the adjuster cap should be positioned
to ensure access is maintained for
subsequent removal.
17.If the air gap is smaller than 0.6 mm the
parameters and functions must be
checked as follows:
a. Apply the brakes to function the brake
chamber.
b. Remove brake chamber. Refer to Section
1 & 2 of your New Flyer Service
Manual for procedure.
c. Check position of lever inside the caliper
in its released state.
d. Inspect the previously removed brake
pads. If necessary, remove dirt from
brake pads, caliper and carrier.
i. Check brake pads for wear from the
tappets and if necessary replace
brake pads.
ii. Check for abnormal wear of the contact
areas of the carrier. If necessary
replace the carrier.
e. Check the brake disc.
18.Check caliper running clearance. Refer to
Section 1 & 2 of your New Flyer Service
Manual for procedure.
19.Install the brake pads. Refer to Section 1 &
2 of your New Flyer Service Manual for
procedure.
20.Install the brake chamber. Refer to Section
1 & 2 of your New Flyer Service Manual for
procedure.
21.Recheck the adjuster.
22.If the air gap is still smaller than 0.6 mm
between both tappets, the brake caliper
must be replaced.
23.Install the wheel.