4 Prepare Parts for Assembly
23Meritor Maintenance Manual 4 (Revised 08-16)
4. Inspect the boot assembly. If it is cracked, cut or torn, remove
the pull pawl and inspect the areas around the actuator. If you
find dirt, solid lubricant or corrosion, replace the slack adjuster.
Otherwise, only replace the boot assembly.
5. Use a grease gun to apply Meritor-approved lubricant to the
slack adjuster grease fitting, until grease flows from around the
camshaft splines and pawl assembly. Refer to Section 7. If
necessary, install a camshaft into the slack adjuster gear to
minimize grease flow through the gear holes.
CamshaftCheck the camshaft for cracks, wear and corrosion. Check the cam
head, bearing journals and splines. Replace worn or damaged
camshafts.
Install new camshaft bushings and seals whenever you install a new
camshaft.
1. Tighten all spider bolts to the correct torque. Figure4.4. @
Figure 4.4
2. Use a seal driver to install new camshaft seals and new
bushings into the cast spider and camshaft bracket.
Figure4.5.
If the brake has a stamped spider: Install both bushings
into the bracket. Install the seals with the seal lips toward
the slack adjuster to ensure grease purges at the slack end.
Figure4.6.
Figure 4.5
Figure 4.6
3. If the camshaft bracket has been removed, install the chamber
bracket seal and bracket onto the spider. Tighten the
capscrews to the correct torque. Figure4.4. @
Camshaft Bushing Journals
1. Inspect the two bushing journals on each camshaft for wear.
2. Remove any debris from the camshaft bushing journals to
ensure an accurate measurement.
3. Use a 1-2-inch machinist’s caliper to measure the bushing
journals on each camshaft. Take the measurement in multiple
positions on the bushing journals as the camshaft and bushing
may wear unevenly. Camshaft journal diameter must be no less
than 1.490-inches (37.846 mm). Figure4.7. @
If any measurement taken on the camshaft bushing
journal surface is less than 1.490-inches (37.846 mm):
Replace the camshaft.
Figure4.4
Bolt Size Torque
7/16"-20 60-75 lb-ft 81-102 N m1/2"-20 85-115 lb-ft 115-156 N m9/16"-18 130-165 lb-ft 176-224 N m5/8"-18 180-230 lb-ft 244-312 N m7/8"-9 440-580 lb-ft 598-789 N m
4000345a
Figure4.5
Figure4.6
4000346a
SPIDER
CAMSHAFTBRACKET
SEALLIP
SEALLIP
4000347a
″
″ ″
″
″
″ ″
″
″
″
″
″
″
″
″ ″ ″
″ ″ ″ ″
″ ″ ″ ″
″ ″ ″
″ ″ ″ ″
″ ″ ″ ″
″ ″ ″ ″ ″
Darkbrown
Tan
White
Cool grey
TP-4786
TP-4787
TP-4781
TP-10130
Truck or tractor drum brakewith 1.38" clevis pin spacing
Trailer drum brake
Coach drum brake with 7-inch or bolt-on slack adjuster
Truck or tractor drum brake with 1.30" clevis pin spacing
″
″
″
Meritor Automatic Slack Adjuster Installation Template for Trucks/Tractors with Drum Brakes with 1.38" Hole Clevis
5" 5.5" 6" 6.5"2297-B-4786 Rev. ”J“SUPERSEDES TP-ASA-1TP-4786
1.38" CLEVISPIN SPACING
BSAP 2.75"FOR BRACKET OFFSETS 3.75" & 3.81"
PLACE ON CAMSHAFT CENTER
ADJUST CLEVIS UNTIL
SMALL CLEVIS PIN
IS WITHIN SLOT
IF T
HIS
EN
D O
F TE
MPLA
TE F
ITS
BET
WEE
N C
LAM
P B
AN
DS O
F SPRIN
G
CHA
MB
ER, I
T IS
A L
ON
G S
TROKE
PLACE OVER LARGE CLEVIS PIN
SLACK ADJUSTER ARM LENGTH
Meritor Automatic Slack Adjuster Installation Template for Trucks/Tractors with Drum Brakes with 1.30" Hole Clevis
5" 5.5" 6" 6.5"
2297-Y-8813 Rev. ”B“TP-10130
1.30" CLEVISPIN SPACING
BSAP 2.25"FOR BRACKET OFFSETS 3.75" & 3.81"
PLACE ON CAMSHAFT CENTER
ADJUST CLEVIS UNTIL
SMALL CLEVIS PIN
IS WITHIN SLOT
IF T
HIS
EN
D O
F TE
MPLA
TE
FITS
BETW
EEN
CLA
MP B
AN
DS O
F SPRIN
G
CHA
MB
ER, I
T IS
A L
ON
G S
TROKE
PLACE OVER LARGE CLEVIS PIN
SLACK ADJUSTER ARM LENGTH
5" 5.5" 6" 6.5"2297-C-4787 Rev. ”G“SUPERSEDES TP-ASA-2TP-4787
1.38" CLEVISPIN SPACING
Meritor Automatic Slack Adjuster Installation Template for Trailers with Drum Brakes
ADJUST CLEVIS UNTIL
SMALL CLEVIS PIN
IS WITHIN SLOT
IF T
HIS
EN
D O
F TE
MPLA
TE
FITS
BET
WEE
N C
LAM
P B
AN
DS O
F SPRIN
G
CH
AM
BER, I
T IS
A L
ON
G S
TROKE
PLACE ON CAMSHAFT CENTER
PLACE OVER LARGE CLEVIS PIN
SLACK ADJUSTER ARM LENGTH
″
″ ″
″ ″ ″
″
PLACE ON CAMSHAFT CENTER
ADJUST CLEVIS UNTILSMALL CLEVIS PINIS WITHIN SLOT
PLACE OVER LARGE CLEVIS PIN
SLACK ADJUSTER ARM LENGTH
Automatic Slack AdjusterTemplate for Coaches with Drum Brakes
5.5" 7"
2297
-W-4
781
Rev
. ”K“
TP-4
781
Meritor Automatic Slack Adjuster Installation Template for Trucks/Tractorswith Drum Brakes with 1.30" Hole Clevis
5" 5.5" 6" 6.5"
2297-Y-8813 Rev. ”B“TP-10130
1.30" CLEVISPIN SPACING
BSAP 2.25"FOR BRACKET OFFSETS 3.75" & 3.81"
PLACE ON CAMSHAFT CENTER
ADJUST CLEVIS UNTIL
SMALL CLEVIS PIN
IS WITHIN SLOT
IF T
HIS
EN
D O
F TE
MPLA
TE F
ITS
BET
WEE
N C
LAM
P B
AN
DS O
F SPRIN
G
CH
AM
BER
, IT
IS A
LON
G S
TROKE
PLACE OVER LARGE CLEVIS PIN
SLACK ADJUSTER ARM LENGTH
″
± ″
″
″
″
″
″
″
″ ″
″
± ″
″
″
″
″
″
″ ″
″ ″
″
± ″
″
″
″
″
″
5 Assembly and Installation
39Meritor Maintenance Manual 4 (Revised 08-16)
7. Install the anchor pin washers, felts, seals, retainers and snap
rings, if required. Install lock pins or lock screws, if required.
Tighten the screws to 10-15 lb-ft (13.6-20.3 Nm). @
8. Install a new shoe return spring onto the brake shoe.
Figure5.30. Place the upper brake shoe into position over the
spider. Repeat Steps 5-6.
Figure 5.30
T Series Cam Brake
1. Lubricate the shoe rollers and anchor pins as shown in
Figure5.28. Use only Meritor-approved grease. Refer to
Section 7 for approved grease specifications.
2. Install the anchor pins, washers and nuts onto the backing
plate if you removed these parts previously. Tighten the anchor
pin nuts to 185-350 lb-ft (251-475 Nm). @
3. Install the anti-rattle rod. Install the brake shoe onto the anchor
pins and anti-rattle rod.
4. Install the anchor pin snap rings, anti-rattle spring and
anti-rattle retainer spring onto the anti-rattle rod.
5. Pull the brake shoe away from the camshaft to enable you to
install the brake shoe roller. Install a new brake shoe return
spring onto the brake shoe.
Brake Shoes Equipped with a Lining Wear Sensor
Before disassembly, note the routing of the sensor wiring. The
wiring harness passes through a dust shield grommet that must be
removed in order to pull the harness connector through the dust
shield. The replacement assembly contains a new dust shield
grommet. Ensure that you route and secure the sensor wiring in the
same manner. Reinstall the connector end of the sensor wiring to
the main harness.
The brake shoe assembly includes a lining wear sensor. The sensor
is located in the primary shoe lining block closest to the camshaft on
the inboard side. The first shoe past the camshaft in the direction of
wheel rotation is the primary shoe.
The primary shoe can either be on the top or the bottom position,
depending on the location of the cam. If the cam is behind the axle,
the top shoe is the primary shoe. If the cam is in front of the axle,
the bottom shoe is the primary shoe. Figure5.31.
The preferred sensor position is the primary shoe, cam end block,
inboard center rivet. Figure5.32.
Figure 5.31
Figure5.30
4000368a
Figure5.31
WHEEL ROTATION WHEEL ROTATION
WHEEL ROTATIONWHEEL ROTATION
CAM BEHIND AXLE
CAM IN FRONT OF AXLECAM BEHIND AXLE
CAM IN FRONT OF AXLE
PRIM
ARY SHOE
SECONDARY SHOE
CAM
SECONDARY SHOE
PRIMARY SHOE
CAMANCHOR ANCHOR
SECONDARY SHOE
PRIMARY SHOE
PRIM
ARY SHOE
SECONDARY SHOE
4006499c
ANCHOR ANCHORCAM
LEFT FORWARD WHEEL ROTATION
RIGHT FORWARD WHEEL ROTATION
CAM
CAM
° °
° °
° °
° °
− ° − °
− ° − °
− ° − °
− ° − °
− ° − °
− ° − °
8 Diagnostics
56 Meritor Maintenance Manual 4 (Revised 08-16)
Shimmy or vibra-
tion occurs when
brakes are applied.
Radial wheel end runout is excessive (as measured on the fric-
tion surface of an assembled drum).
Verify correct hub mounting and wheel bearing end
play. If both are correct/within specification, refer to
“Check Runout on an Assembled Brake Drum” in
Section 6 of Maintenance Manual MM-99100,
Wheel Equipment, Disc Wheel Hubs, Brake Drum
Failure Analysis.
The hub-piloted brake drum is mounted incorrectly. Remove the drum and inspect the hub pilots for
damage. Clean the drum mounting surfaces on hub
and drum. Re-mount the brake drum onto the hub,
making sure the drum pilot bore is correctly seated
on the hub pilots.
Wheel bearing end play is excessive. Adjust or repair the wheel bearings to the correct
manufacturer’s specification.
Drum is out of balance or missing weights. Repair or replace the drum per the manufacturer’s
guidelines.
Discrepancies exist in brake adjustment. Follow the diagnostic procedure for "The adjusted
stroke is too short" or "The adjusted stroke is too
long" as it applies.
Brake wear is inconsistent. Perform the Brake Burnish procedure found in the
Assembly Section of this manual.
Brake components (i.e. springs, rollers retainers) are broken or
missing
Repair or replace components as necessary.
Different length slack adjusters are used on the same axle. Install the same length slack adjusters from the
same manufacturer on the same axle.
Different brake chamber sizes are used on the same axle. Install the same size and type brake chambers on
the same axle.
Brake attaching hardware is broken, loose or missing. Repair or replace components as necessary.
Tire runout is excessive. Verify the tire radial runout is below the manufac-
turer’s maximum recommended measurement.
Replace as necessary.
Wheel lateral or radial runout is excessive. Verify the wheel lateral and radial runout are within
manufacturer’s specifications. Replace as neces-
sary.
Vehicle is out of alignment. Verify the vehicle total axle alignment (both steering
and drive axles) is within manufacturer’s
specifications. Repair as necessary.
Steering or suspension hardware or components are loose. Follow the OEM guidelines for inspection,
maintenance and repair of the steering and
suspension systems.
Symptoms Possible Causes Corrective Actions
8 Diagnostics
57Meritor Maintenance Manual 4 (Revised 08-16)
Brake squeal/
chatter/noise
occurs upon brake
application.
Brake components (i.e. springs, rollers retainers) are broken or
missing.
Inspect, repair and/or replace components as
necessary.
Brake attaching hardware is broken, loose or missing. Inspect, repair and/or replace components as
necessary.
Brake wear is inconsistent. Perform the Brake Burnish procedure found in the
Assembly Section of this manual.
Linings are glazed (20% or less of lining friction surface). Perform the Brake Burnish procedure found in the
Assembly Section of this manual.
Linings are glazed (greater than 20% of lining friction surface). Determine the cause of overheating in the brake
assembly and repair accordingly.
Lining selection is incorrect. Replace with original equipment lining brand and
type.
The drum brake surface is aligned with shoe high spots on the
brake lining.
Make sure the service parts are correct. Perform
the Brake Burnish procedure found in the Assembly
Section of this manual.
Symptoms Possible Causes Corrective Actions
″
″
″
″