4-32. FRONT AXLE - Continued
(1) Disconnect air line (1) from front axle differential lock air shift unit.
(2) Remove and retain capscrew and clamp attaching breather (2) to frame. Tape vent hose to axle
(3) Disconnect air hoses (3) from both left and right brake chambers (4).
(4) With trolley jack placed underneath differential housing, support front axle and remove nuts (5) and U-bolts
(7). If nuts and U-bolts are too corroded, flame cut the U-bolts.
(5) Scribe spring plates (6) with alignment marks and remove from top of spring.
(6) Lower trolley jack and maneuver the front axle out from underneath the truck.
(7) Disconnect vent line from axle housing if new axle is to be installed.
(1) Visually inspect axle assembly for damage, and oil and grease leaks. Pay particular attention to pinion
seal area and wheel end ball seals.
(2) Inspect tie rod and tie rod ends, brake drums, brake air chambers, and vent hose components. Replace
components showing signs of excessive wear or damage.
(1) Install vent hose on front axle, if required.
(2) If new axle, remove plug from differential lock air shift unit and replace with 1/4 in. setscrew. Apply
threadlock liquid (item 29, Appendix E) prior to installation.
(3) Support axle with trolley jack under the differential and maneuver the axle under the truck
(4) Align axle with springs. Apply threadlock liquid (item 29, Appendix E) to nuts (5). Install U-bolts (7)
through spring plate (6) and secure with nuts (5). Note that two different U-bolts are used. The wider U-
bolts must be installed inboard of the springs.
(5) Be sure axle and springs are properly aligned and spring plate scribe marks are aligned before firming up
nuts (5). Tighten nuts to 300 ft lb (410 Nm).
(6) Coat threads with pipe sealant (item 22, Appendix E) and install air line (1) on differential lock air shift unit.
(7) Coat threads with pipe sealant (Item 22, Appendix E), and install air hoses (2) on both left and right brake
air chambers (4)
(8) Install axle breather (2) on frame using capscrew and nut as shown.
(9) If a new axle is installed, be sure to carry out tie rod adjustment as detailed in para. 4-32.2, and steering
gear and drag link adjustment as detailed in para. 4-25.6.