TM 9-2330-246-14
4-63. AIR CHAMBER MAINTENANCE (Con't).
MASTER CYLINDER
REMOVED FOR CLARITY
PUSHROD TRAVEL TEST
d.
NOTE
Semitrailer must be coupled to towing vehicle (para 2-1O).
With brakes released, insert a small rod (4) through one of two inspection holes (7) in left side of air chamber (2).
1.
Mark rod, indicating depth of penetration when contacting pushrod.
Apply brakes, insert rod (4) fully, and mark rod again.
2.
Withdraw rod (4) and measure distance between marks. Distance between marks indicates the amount of travel
3.
of pushrod (3).
Pushrod (3) travel requirements are as follows:
4.
(a) Old style air chamber. Pushrod travel not less than in. (12.7 mm) and not greater than 7/8 in. (22.2 mm).
(b) New style air chamber. Pushrod travel not Iess than in. (12.7 mm) and not greater than 1 in. (3.8 cm).
If pushrod (3) travel is correct, adjust brakes (para 4-55 or 4-56).
5.
If pushrod (3) travel is not correct, replace air chamber.
6.
TA700259
4-155
