adiuster rotates the camshaft, which forces the brake
A i r hoses should be checked for chafing,
shoes against the brake drum.
bends, andkinking every month/2000 miles. Replace
424. OPERATING CHECKS.
4 - 2 5 . During road stops, take time to check the
4 - 1 7 . AIR BRAKE CHAMBERS.
brake drums for a heating condition. Proceed cau-
tiously since malfunctioning or misadjusted brakes
4-18. The air system tests in paragraph 4-12 should
can case the drum to become extremely hot. Valve
disclose any malfunctioning brake chambers. Repair
stems may be burned by the hot drum. Do not at-
or replace faulty units.
Every 2,000 miles check the
tempt to operate the vehicle until the problem caus-
c o n d e n s a t i o n holes on the underside of the brake
ing the overheating is corrected. A cool brake drum
chambers to make sure they are open.
may indicate an inoperative brake. Test is outlined
c h a m b e r s should be disassembled and cleaned at
in paragraph 4-12.
50,000 miles or yearly.
The diaphragm and any mar-
ginal parts should be replaced. When replacing the
4 - 2 6 . BRAKE ASSEMBLY.
diaphragm or spring, replace the corresponding ports
for the other chamber on the same axle (to aid in
even brake application and release). Examine yoke
Remove the dust shields and examine the
pin for wear and replace if necessary.
brake linings visua 1 ly to locate the
lining showing the greatest amount of
4 - 1 9 . RELAY EMERGENCY VALVE.
The wheel and drum should be re-
moved and the lining replaced
4 - 2 0 . The air system tests in paragraph 4-12 may
thinnest portion of the lining
disclose a malfunction of the reloy emergency valve.
Repair or replace faulty units. The relay Valve
linings to wear thin enough so the lin-
s h o u l d be disassembled and cleaned every 50,000
ing rivet contacts the drum (see Figure
R e p l a c e worn parts. Contact an
miles or yearly.
authorized representative of the original equipment
manufacturer for relay valve servicing.
Grease the camshaft
ing and the spider bushing
at 4 locations
DO NOT use an ex-
cessive amount of grease on the anchor
pins and spider bushing to avoid getting
4 - 2 3 . HYSTER trailers are equipped with cam ac-
B r a k i n g force is supplied by air
pressure in the brake chamber, which pushes a push-
4-29. SLACK ADJUSTER.
rod against the end of the slack adjuster. The slack
sate for brake lining
grease slack adjusters
FIGURE 4-3. BRAKE BLOCK WEAR.
FIGURE 4-4. GREASE ZERK LOCATIONS
Change 3 4-4