TM-5-2330-378-14-P

SEMITRAILER, LOWBED: 40 TON CONSTRUCTION EQUIPMENT TRANSPORTER M870 AND M870A1

TECHNICAL MANUAL; OPERATOR'S, UNIT, DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL (INCLUDING REPAIR PARTS AND SPECIAL TOOLS LIST)

JUNE 1999

TM-5-2330-378-14-P - Page 303 of 524

TM 5-2330-378-14&P

5-14. BRAKEDRUMREPAIR(M870AND M870A1)(continued).

NOTE

• Slightscoringon brakedrumcanbecorrectedbypolishingwithabrasive(crocus)cloth. It

brakedrum

is heavily scored or out-of-round,

it must be refaced.

• Whenever brakedrum on one side of axle is refaced, the other brakedrum on that axle

should be refaced to the same specifications.

4.

Using micrometer,

check inside of braked rum (1) if four places for out-of-round

or tapered wear. Recordeach

reading. The maximum difference between the four readings cannot exceed 0.062 inch (1.5888 mm).

Brakedrums

with out-of-round

exceeding limits must be refaced.

FOUR READINGS

START POINT

900

READING

POINT

450 READING

POINT

45'READING

POINT

I

F

450 READING

POINT

450 READING

POINT

NOTE

It refacing causes brakedrums

to exceed original diameter by more than 0.80 inch

(2.032 mm) for the M870 or 0.060 inch (1.524 mm) for the M870A1, replace

brakedrum.

The other brakedrum on that axle should be replaced also.

5.

Reface inner braking surface (2). Make several thin cuts until grooving or scoring defects have been removed.

Check brakedrum

diameter after each cut to make sure you have not cut out too much metal.

6.

Reface other brakedrum

on the same axle to the same specifications.

FOLLOW-ON

TASKS:

Install hub and brakedrum

on axle (para 4-68 or 4-69).

5-41