Midland Manual Slack Adjusters
Midland slack adjusters are greased for life at as-
sembly. However, a grease fitting is furnished to per-
mit optional lubricating.
42–12 Automatic Slack
Adjuster Checking,
Meritor
1. Check the boot for cuts, tears, etc., and replace
it if necessary. See Fig. 6.
2. Check the brake shoe lining wear to determine
the proper reline time. For instructions, see
Brake Lining Wear Checking, Hydraulic Disc
Brakes.
3. Check the free-stroke. If the vehicle has new
brakes or brakes with new linings, you must
check the free-stroke. If the vehicle is in for rou-
tine maintenance and the brakes or linings are
not new, go to the next step and check the brake
chamber stroke.
IMPORTANT: Do not use installation tem-
plates to check the slack adjuster angles.
Installation templates are used only when
installing a new slack adjuster or reinstalling
the existing slack adjuster.
3.1 With the brakes fully released, measure
the distance from the bottom of the brake
chamber to the center of the large clevis
pin. See Fig. 7, Ref. A.
3.2 Use a pry bar to move the slack adjuster,
applying the brakes. Again, measure the
distance from the bottom of the brake
chamber to the center of the large clevis
pin. See Fig. 7, Ref. B.
The difference between the two measure-
ments is the initial free-stroke, and sets
the clearance between the linings and the
drum. The free-stroke must be:
• drum brakes—5/8 to 3/4 inch (16 to
19 mm);
• disc brakes—7/8 to 1-1/8 inch (22
to 29 mm).
f420012a
10/20/93
1
2
3
4
5
6
7
1. Brake Chamber
2. Clevis
3. Actuator Rod
4. Boot
5. Pressure-Relief Capscrew, Gasket, Pawl Spring,
and Pawl
6. Manual Adjusting Nut
7. Grease Fitting (or Lube Plug)
Fig. 6, Meritor Automatic Slack Adjuster
A
B
09/27/94
f420180a
NOTE: For a drum brake, A minus B must equal 5/8" to
3/4" (16 to 19 mm). For a disc brake, A minus B must
equal 7/8" to 1-1/8" (22 to 29 mm).
A. With the brakes applied, measure this distance.
B. With the brakes released, measure this distance.
Fig. 7, Measuring Free-Stroke
Brakes42
Business Class Trucks Maintenance Manual, October 199842/8
To Next Page
Loading...
