Thomas SAF-T-LINER C2, Maintenance Manual

Page: 63 / 176

25–04 Clutch Hydraulic Fluid
Changing
Replace the clutch hydraulic fluid every two years to
ensure clutch function is reliable and correct. Use the
procedures below. Fluid replacement must be done
at an authorized Freightliner service facility.
Flushing
1. Shut down the engine.
2. Apply the parking brake, chock the front and rear
tires, and raise the hood.
WARNING
Clutch hydraulic fluid (DOT 4 brake fluid) is haz-
ardous. It may be a skin irritant and can cause
blindness if it gets in your eyes. Always wear
safety glasses when handling clutch hydraulic
fluid or bleeding hydraulic lines. If you get clutch
hydraulic fluid on your skin, wash it off as soon
as possible.
3. Prepare the pressure bleeding equipment ac-
cording to the manufacturer’s instructions. Use
DOT 4 brake fluid. Pressurize the bleed adaptor
to 15 psi (103 kPa).
CAUTION
Do not spill clutch hydraulic fluid (DOT 4 brake
fluid) on the body paint. Clean it off immediately if
any is spilled. DOT 4 brake fluid can damage
paint.
4. Remove the reservoir lid and install the pressure
bleed adaptor on the reservoir.
5. Pressurize the reservoir, filling the system. Open
the bleed valve on the bleed tank of the adaptor.
NOTE: A pressure bleeder hose (J-29532) and
a bleed adaptor (J-35798) for the fluid reservoir
are available through SPX Kent-Moore Tools
and may be used to complete the following pro-
cedure. To order these parts, call Kent-Moore at
1-800-328-6657.
6. Flush the hydraulic system, as follows. See Fig.
6 .
6.1 Open the bleed screw on the slave cylin-
der.
6.2 Using a drain pan or other suitable con-
tainer, collect the fluid that drains from the
slave cylinder bleed valve, at least 0.5
quarts (0.5 liters).
6.3 When all the old fluid has passed through
the system and only new, clean fluid is
coming out, close the bleed screw.
7. Check the fluid level in the reservoir and bleed
the system according to the procedure under the
heading "Bleeding the Clutch." See
Fig. 7 .
Bleeding the Clutch
1. Remove the cap from the bleed valve. Install a
transparent drain hose on the bleed valve of the
slave cylinder.
2. Open the slave cylinder bleed screw. Observe
the flow of clutch hydraulic fluid through the drain
hose. When no bubbles appear in the fluid, close
the slave cylinder bleed screw.
3. Disconnect the transparent hose. Tighten the
bleed screw 88 lbf·in (1000 N·cm) and install the
cap on the slave cylinder bleed valve.
4. Close the valve on the bleed tank of the pres-
sure bleed adaptor. Remove the pressure bleed
adaptor.
5. Check the fluid level in the reservoir. If neces-
sary, add or remove clutch hydraulic fluid to bring
the fluid level to the MAX line. Install the reser-
voir lid.
CAUTION
When removing fluid from the reservoir, use a
clean tool that is used only for brake fluid. Using
a tool contaminated with oil or chemical residue
will destroy hydraulic system parts and cause the
system to malfunction.
6. Depress the clutch pedal a few times. There
should be resistance over the full pedal stroke.
7. Check the entire system for leaks. Tighten the
connections between the components if neces-
sary. Check the fluid level in the reservoir again.
8. Make sure the reservoir lid is tight.
Clutch
25
Saf-T-Liner C2 School Bus Maintenance Manual, June 2015
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