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TM 10-3930-671-24
Inching Troubleshooting Guide
Inching and braking system for trucks with TA18 transaxle
Condition
Probable Cause
Remedy
1-Will not inch and/or partial clutch disengagement.
1.
Air in lines prevents adequate inching
1)
Bleed inching system. Check if truck inches correctly.
slave cylinder movement.
2)
If air entrapment remains a problem after bleeding inching
system:
a)
Remove the bolt-on casting from the front side of the
control valve.
b)
Bleed down brake pedal and block pedal, as noted in
inching bleeding procedures.
c)
Stroke the inching pedal 3-7 times until pedal abruptly
bottoms out. Push in the plunger which protrudes from the
control valve while bleeding at transaxle slave cylinder
bleeding screw. Repeat until all air has been evacuated from
system.
d)
Reinstall casting. Be sure no dirt has entered the control
valve and the 3 O-rings are properly installed.
e)
Remove brake pedal block. Recheck if truck will inch.
2.
Inching actuation system leaking.
1)
Loose fitting
1)
Tighten fitting correctly.
2)
Stripped fitting
2)
Replace fitting (typically a brass adapter fitting).
3)
Loose bleeder screw
3)
Tighten bleeder screw.
4)
Defective master cylinder
4)
Replace master cylinder.
3.
No inching pedal freeplay.
1)
Adjust pedal stop screw.
(1 /4-inch nom. travel required at pedal foot pad)
2)
If full adjustment can not be made and if head of stop
screw is on under side of bracket, then remove screw
and install with head on top of bracket. Readjust.
4.
Inching push rod too short / master
1)
Check if adjustable pushrod is correctly on inching side
cylinder does not travel fully.
and not on the brake side.
(Note - Pedal up height is directly related to stroke)
2)
Check for correct quantity of adjustor washers on
adjustable inching pushrod assembly.
3) Check pushrod lengths: brake pushrod hole center to end
=4.41 in.(112 mm); inching pushrod (with no washers) = 4.33
in. (110 mm).
4)
Brake applied before inching complete.
4)
Check brake shoe gap adjustment. Back off if clearance is
less than than .010 in.
5.
Transmission slave cylinder piston stuck.
1)
Piston seal missing, damaged, swelled, etc.
1)
Replace seal.
2)
Piston or cylinder scored.
2)
Replace slave cylinder.
3)
Piston or seal installed backwards.
3)
Reinstall parts correctly.
F-388
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