4. Remove the retaining bolts holding caliper to axle and remove caliper. If
necessary, loosen a bleeder to relieve pressure (This will necessitate bleeding the
brakes later.).
5. Knock the tabs holding pads in place back, and remove pads
6. Check pistons for leakage, corrosion, and gumming. If necessary, disassemble
and service the caliper, see 1.4.3.
7. Using a C-clamp (surface that contacts pad MUST be clean.) on each piston, force
pistons into caliper to allow caliper to fit over disc.
8. Install new pads.
NOTICE! Small metal tabs project through the mounting holes of the outboard brake pads
on the outside of the caliper. To keep the pads from floating, peen the tabs over the edge of
the hole. This should extend the life of the outer pad and eliminate premature rotor wear.
Do this in assembly with the rotor while applying pressure to the caliper to prevent the
mounting bolts from bending. To insure that the caliper floats check for adequate grease in
the caliper mounting sleeves, we recommend Stalube #3303 synthetic brake caliper
grease with added graphite and teflon.
9. Reassemble brake caliper to caliper bracket. Insert caliper pins with blue Loctite.
Tighten bolts to 35-40 ft-lbs torque.
10. Check that the caliper and pads are centered over (parallel to) the disc.
11. Install wheel assembly and tighten lug nuts (front) per Chapter 2. Remove safety
stands and lower tractor.
After initially mounting wheel and tire assembly, recheck lug nut torque
after the first hour of operation and after the first 8 hours of operation. After this, check
monthly or every 250 hours, whichever comes first. Do not lube wheel studs as it will result
in inaccurate tightening torque. Failure to follow these procedures could result in wheel
mounting failure and loss of vehicle control.
12. If air was allowed to enter the hydraulic system, bleed brakes according to Chapter
2.
13. Pump brake pedal to force pads against disc. Check fluid reservoir and bring to
correct level.
14. Road test the tractor to test brake action. The tractor should stop quickly and
smoothly with no tendency to dive or pull to one side.
1.4.2 Disc Replacement (Front)
Refer to 1.4.3
AUGUST 31, 2008 CHAPTER 3 OVERHAUL
PAGE 4 1 GENERAL REPAIR
M140 Tow Tractor Manual No. 46054
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