SECTION XI. BRAKE PROBLEMS-M151 SERIES
1. The improved rear differential mounting bracket on 1/4-ton trucks can rub a hole in the brake line, leaving you without
2. Take a look at the hose. There should be at least
1/8-in clearance between the line and the top of the
bracket, and 1/2-in of space at the bottom.
3. If there's not enough clearance, move the hose
gently. Bend the brake line at the "T" and turn the hose
clamp on top of the rear suspension arm. You must be
careful not to move them more than they need.
Once the line is in the clear, have an assistant apply
the brakes while you check the line for leaks.
5. M151 Brake Cylinder Matchup - Wheel brake cylinders come in two sizes for the 1/4-ton trucks. Mixing them makes
the brakes unsafe. M151 and M151Al's use 3/4-in brake cylinders, assigned NSN 2530-01-071-9851, on the front and
rear brakes. M151A2's use 3/4-in cylinders on the rear, but on the front they need 1-in cylinders, assigned NSN 2530-01-
071-9850. The size is stamped on the cylinders.