TRUCK SERVICE MANUAL
HYDRAULIC BRAKE FLUID
As a result of use, brake fluid becomes contaminated
and loses some of its original qualities. It is good practice to
bleed the brake system until all old fluid is removed when
performing major brake work. Also, the old fluid should be
bled from the system and replaced with clean brake fluid if
any of the hydraulic system parts are corroded, fluid is
discolored, contains water or is dirty.
If any of the rubber parts of the hydraulic system are
soft or swollen, old fluid should be removed; the hydraulic
system should be flushed with alcohol or clean brake fluid and
refilled with brake fluid. (All cups and seals should also be
replaced.) Do not reuse old brake fluid. For type of fluid, refer
to CTS-2412 in your Service Manual under LUBRICATION.
Check linings for being too thin, uneven wear,
damaged, soiled with grease or brake fluid, or for
being loose on the shoes. Whenever brake linings or
blocks are worn to within .79 mm (1/32") of rivets on
light duty vehicles or 1.59 mm (1/16") of rivets on
medium or heavy duty vehicles, the brake shoes
must be removed and relined. It is recommended
that all the brakes be relined at the same time since
this will maintain balanced braking of the vehicle. If
complete replacement is not desirable or necessary,
be sure that all lining on one axle (both sides) is
replaced at the same time.
Intermixing of various types of lining material other than that
specified is not recommended.
Examine brake shoes for worn anchor ends,
damaged rims or webs, or cracked or broken welds.
Mechanical parts should be checked for heat
damage, broken ends or loss of tension in shoe
return springs, wear or corrosion of shoe hold-down
pins, springs and cups, wear on adjusting screw,
looseness of mounting or anchors and worn shoe
ledges on backing plate.
1. Check brake drums for scores, heat checks,
out-of-roundness and oversize.
Wheel bearings should be checked for wear. Also,
check grease seals for evidence of grease leaks.
Refer to WHEEL Service Manual sections.
VACUUM POWER CYLINDER (Hydrovac) AIR CLEANER
Vehicles with vacuum power cylinders, which do not
have a direct air source to the engine air cleaner, will have a
frame mounted air cleaner (Fig. 4 and 6). This air cleaner
may be located either on the outside of the frame or to the
inside of the frame.
If this air cleaner is mounted on the outside of the
frame, it is suggested that it be relocated inside the frame
away from direct road splash from the wheels.
The location of this air cleaner will be on the left
frame rail under the cab in the area adjacent to the power
Maintenance Interval Replaceable Element Type (Fig. 4)
19,000 km (12,000 miles)
Remove element and clean by tapping gently on a
flat surface or use low air pressure. DO NOT WASH OR OIL
58,000 km (36,000 miles)
Vehicles operating under multi-stop or severe dust
conditions will require cleaning or replacement of filter
element more often.
Fig. 4. Air Cleaner Assembly (Replaceable Element Type)
CTS-2055S Chapter 1 Page 5
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