Yale ERP15-20VT Service Manual page 28

Master Cylinder Repair
To bleed air from the brake system:
1. Remove the floor plates and check that the master
cylinder reservoir is full of oil.
2. One technician must sit in the seat and repeatedly
press and release (pump) the brake pedal to in-
crease the back pressure. The brake pedal may
become harder to press as this occurs.
3. When back pressure seems to be at the maximum,
the technician must press and hold the pedal as far
as it will go.
4. The second technician must slowly loosen the
bleed valve on one of the transaxle housings be-
tween the wheel and the frame. Air and oil should
bubble from the valve until the pedal is pressed to
its mechanical travel limit.
5. The pedal should be held in this position while the
valve is retightened.
6. Repeat Step 2 through Step 5 until oil with no air
(bubbles) flows from the valve. Check the oil level
in the master cylinder every cycle and fill reservoir
as necessary.
7. Perform Step 2 through Step 5 on the other
transaxle until all air has been bled from the sys-
tem.
Adjust Linkage
To adjust the master cylinder linkage:
1. Check that the pedal is adjusted properly before ad-
justing the master cylinder linkage. Refer to Brake
Pedal Assembly Repair section for procedures.
2. Loosen the lock nut on the push rod. See Figure 10.
8
NOTE: Do not allow the boot to be twisted while adjust-
ing the push rod length.
3. Turn the push rod to counterclockwise (as viewed
from rear of truck) to remove all slack between the
master cylinder and the brake pedal.
4. Turn the push rod 1/8 clockwise (as viewed from
rear of truck) to allow the master cylinder to fully
return when the brake pedal is released.
5. Hold the push rod in position, and tighten the lock-
nut on the push rod against the clevis to secure in
place.
1. SPRING
2. BRAKE PEDAL
3. WASHER
4. CLEVIS PIN
5. COTTER PIN
Figure 10. Linkage Adjustment
1800 YRM 1332
6. CLEVIS
7. LOCKNUT
8. PUSH ROD
9. BOOT