Model MA TOW Tractor. Manual - part 18

Chapter 3: Overhaul

Dec. 1995                     Section 3-5                        p. 3

(c)

Slowly pull pistons from caliper housing.

(d)

Using sharpened wooden or soft plastic dowel, remove seal from groove inside bore.

CAUTION: DO NOT SCRATCH, BURR OR OTHERWISE DAMAGE OUTSIDE OF
PISTON OR INTERIOR OF BORE.

3.

Caliper Cleaning:

WARNING: NO SMOKING, FIRE OR OPEN FLAME IS PERMITTED  IN AREAS WHERE
ALCOHOL IS BEING USED. AVOID INHALATION OF FUMES.

(a)

Clean all parts with alcohol.

(b)

Use air hose to blow-out all fluid passages.

(c)

Use lint-free cloth to dry.

(d)

Repeat above steps until all components are thoroughly cleaned.

4.

Caliper Inspection:

(a)

Inspect itnerior of calipers for evidence of cracks or leakage.

(b)

Closely inspect lugs and bolts for evidence of cracks or excessive corrosion.
If cracked or excessively corroded, replace with new parts.

WARNING: REPLACE CALIPERS AND BOLTS ONLY WITH SAME PARTS NO’S
AS ORIGINAL.

(c)

Inspect piston and bores for burrs, scratches or evidence of wear.

NOTE: (1)  A black stain on a piston or in a bore was probably caused by the boots
or seals and should not be considered as cause for replacement.

(2) Slight scratches on the interior of the bore can be tolerated. No scratches on the

piston exterior surface can be permitted.

(d)

Discard all old seals and dust boots.

5.

Caliper Assembly:

(a)

Use vise to hold caliper halves as an assembly aid.

(b)

Wet seal in brake fluid and position in bore. By sliding finger around interior of bore,

press seal into groove.

CAUTION: BE SURE SEALS ARE NOT TWISTED OR ROLLED.

Chapter 3: Overhaul

Dec. 1995                     Section 3-5                        p. 4

V.

REAR WHEEL DISC BRAKES (SERIAL NO'S 0001 THROUGH 0127)

B.

CALIPER AND ROTOR

5.

Caliper Assembly (cont)

(c)

Wet dust boot with brake fluid and install it in groove around upper edge of bore.

(d)

Coat outside surface of piston with brake fluid.

(e)

Stretch dust boot around piston and slowly slide piston into bore until groove along

top of piston is approximately even with top of dust boot.

CAUTION: USE FIRM EVEN PRESSURE TO SLOWLY FORCE PISTON INTO BORE.
ABRUPT FORCES MAY CAUSE PISTON TO COCK SIDEWAYS OR DAMAGE SEAL.

(f)

Fit upper rim of dust boot into groove in piston.

(g)

Press piston by hand into bore as far as it will go without pinching boot.

(h)

Loosely install bleeder screw.

6.

Installation:

WARNING: REPLACE BOLTS AND NUTS ONLY WITH ORIGINAL PART NUMBERS.

(a)

Attach caliper half (lugged) to axle housing flange with bolt, nut, and washer with

washer against caliper.

NOTE: Turning nut only, torque to 30-40 foot-pounds (40-54 N-m), then install cotter pin
with “loop” of pin upward.

(b)

Secure wheel hub to rotor using four (4) lugnuts and slide rotor and hub onto axle.

(c)

Attach remaining caliper halr to mounted half using bridge bolts with lockwashers

and torque 70-80 foot-pounds (95-108.5 N-m).

(d)

Install and tighten fluid crossover line.

(e)

Slide brake shoes into place with shoe linings facing each other and ears of shoes

resting on caliper bridge.

(f)

Install brake shoe retaining clips.

(g)

Install axle nut and washer. Torque nut to 400-500 foot-pounds (542-678 N-m).

Install cotter pin.

(h)

Reconnect brake fluid lines.

(i)

Add fluid to master cylinder, if needed.

Chapter 3: Overhaul

Dec. 1995                     Section 3-5                        p. 5

(j)

Bleed brakes at calipers to assure system is full of fluid and free of air. Add fluid as

needed.

(k)

Remove lugnuts from studs.

(l)

Mount the wheel.

(m)

Lower vehicle from jacks.

7.

Check-out:

(a)

Check brake pedal for sponginess or hard pedal.

(b)

Drive tractor slowly and make several slow speed stops.

(c)

Check all brake fluid line fittings and caliper areas for fluid leakage.

(d)

Correct any discrepancies before returning tractor to normal service.

C.

ROTOR:

1.

Removal:

Remove rotor as described in Section B.1 above.

2.

Disassembly:

Remove lug nuts thereby separating rotor from hub.

3.

Cleaning:

WARNING: NO SMOKING, FIRE OR OPEN FLAME IS PERMITTED
IN AREAS WHERE ALCOHOL IS BEING USED. AVOID INHALATION OF FUMES.

(a)

Clean rotor with alcohol.

(b)

Use lint-free cloth to dry.

4.

Inspection:

(a)

Inspect weldments for evidence of corrosion or cracking. Replace if cracked or

severely corroded.

(b)

Inspect rubbing surfaces for evidence of corrosion, pitting or scratches. Replace if

scratched, corroded or pitted.

Chapter 3: Overhaul

Dec. 1995                     Section 3-5                        p. 6

V.

REAR WHEEL DISC BRAKES (SERIAL NO'S 0001 THROUGH 0127)

C.

ROTOR (CONT)

NOTE: All rotors having a plate thickness of less than .450 should be scrapped. All others
should be returned to TUG for testing and re-surfacing. No on-site resurfacing should be
attempted.

5.

Assembly:

Using four (4) lug nuts, fasten hub and rotor together.

6.

Installation:

Install rotor as described in Section B. 6 above.

7.

Check-out:

Conduct check-out as described in Section B. 7 above.