MCi MC8 Crusader - Page 3

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MAINTENANCE

Crusader

MC-8

[

,.c,_1-_1

___

DATE~J~ul+-+-y,~19~73~-l

MANUAL

FRONT

AXLE

FRONT

AXLE

DESCRIPTION

The

front

axle

is

of

I-beam

construction

using a

forged

center

and

steering

knuckles.

Steering

knuckle

pins

a~e

tapered,

drawn

into

the

axle

center

by

tighten

mg the

nut

at

the

upper

end

of

the

pin.

The

pin

then

becomes

an

integral

part

of

the

axle

center.

Steering

knuckles

are

bushed

in

the

upper

and

!owe~

pin

bosses so

that

they

may

turn

freely about.

the

pms.

Bronze

bushings with

grooves

on

the

inside

allow

grease

to

flow

uniformly

to

high-pressure

areas.

Grease

fittings

are

installed

at

both

upper

and

lower

knuckle

pin

bosses.

The

two steering

knuckle

assemblies

are

connected

to each

other

by

the

tie

rod

which

is

threaded

at

each

end

and held

securely

in

position

by clamps.

Right-hand

and

left-hand

threads

are

provided

to

simplify toe-in adjustment.

Wheel

bearings,

air

suspension, steering,

and

brake

parts

which

are

mounted

on

the

front

axle

are

described

in

the

applicable

sections

of

this

manual.

FRONT

END

ALIGNMENT

Correct

front

end

alignment

must be

maintained.

for ease

of

steering

and

satisfactory

tire

life.

Road

-~hock,

vibrations,

normal

stresses

and

strains

set

up

m

the

front

end

system

under

average

operation

can

result

in loss

of

front

end alignment.

If

incorrect

front

end

alignment

is

suspected,

front

wheel

balance

should

first be

checked

to

make

sure

that

the

difficulties

are

not

originating

from

out-of.

balance

front

wheels. A check

of

tire

inflation,

wheel

installation

and

run

out,

wheel

bearing

adjustment,

tie

rod

and

drag-link

end

wear

should

also be made.

_Correct

front

end

alignment

can

only

be main-

tamed

when

parts

in the

steering

knuckle

are

in

satisfactory

condition.

Factors

in

front

end

alignment

are

as follows:

1.

Front

wheel toe-in:

The

distance

the

wheels

are

closer

together

at

the

front

than

at

the

rear.

2.

Front

wheel camber:

The

amount

the

wheel

in-

clines from

the

vertical

plane.

"Positive"

camber

means

the

wheels lean

outward

at

the

top.

"Negative"

camber

means

the

wheels lean

inward

at

the top,

and

"Zero"

camber

means

that

the

wheels

are

in a

vertical

plane.

3.

Axle

caster:

The

fore

and

aft

inclination

from

vertical

of

the

steering

knuckle.

"Positive"

caster

is

inclination

of

the

top

of

the

steering

knuckle

towards

the

rear

of

the vehicle.

"Negative"

caster

is

the

inclination

of

the

top

of

the

steering

knuckle

towards

the

front

of

the vehicle.

"Zero"

caster

means

no

inclination

of

the

steering

knuckle.

4. King

pin

inclination:

The

amount

king

pins

are

inclined

inward

at

the

top.

5. Steering

Geometry:

The

science

of

keeping

the

front

wheels in

proper

alignment

during

left

or

right

turns.

CAMBER

ADJUSTMENT

Before

checking

front

wheel

camber

jack

up

the

front

axle

of

the

vehicle

and

check

wheel

bearings

and

steering

knuckle

pins.

To

do

this

attach

a

camber

gauge

to

the

wheel

collar,

pull

outward

at

the

bottom

to

take

up

all slack

and

take

the

camber

reading.

If

the

reading

differs

more

than

1 /4

of

1

degree,

adjust

the

wheel bearings

and

repeat

the

check.

If

-

the

second

reading

is

still

different

in

excess

of

1/4

of

1

degree,

replace

the

steering

knuckle

bushings

and

pins.

Check

wheel

run

out

for

excessive

wobbling.

Correct

any

discrepancy

either

by

straightening

or

replacing

the

wheel.

A final

camber

reading

should

be

made

with

the

full weight

of

the

coach

on

a

level

floor.

Camber

readings

can

be

made

as

illustrated

in

the

alignment

charts

if

no

camber

gauge

is

available.

The

difference

between

the

two

readings

(B

minus

A)

should

not

vary

more

than

3/32"

"!

1

/8"

from

one

wheel

to

the

other.

A

larger

difference

is

usually

due

to

a

bent

axle

or

a

bent

steering

knuckle.

To

determine

if

the

axle

is

bent,

check

the king

pin

inclination

(U

minus

V

on

the

chart).

If

the

king

pin

inclination

is

correct,

the

trouble

is

a

bent

steering

knuckle

which

should

be

replaced.

FRONT

WHEEL

TOE-IN

Toe-in

is

utilized

to

prevent

undue

tire

wear.-To

measure

and

adjust

toe-in,

the

following

procedure

is

recommended:

1.

Jack

up

the

front

axle.

2. Using a piece

of

chalk,

whiten

the

center

area

of

both

front

tires

around

the

entire

circumference.

3.

Position

a

scribe

or

pointed

instrument

against

the

whitened

part

of

each

tire

and

rotate

the

tires.

The

scribe

must

be

held

firmly

so

that

a

single

straight

line

is

scribed

all

the

way

around

the

tire.

4.

Place

a full-floating

turning

radius

gauge

plate

under

each wheel.

Lower

the

vehicle

and

remove

the

lock

pins

from

the

gauge

plates.

If

full-

floating

turning

radius

gauge

plates

are

not

available,

lower

the

vehicle

and

move

it

back-

ward

and

then

forward

approximately

six feet.

5. Set

the

sliding

scale

end

of

a

trammel

bar

on

zero

and

lock in place.

Position

the

bar

at

the

rear

of

the

tires

and

adjust

the

pointers

to

line

up

with

the

scribe

lines on

the

tires

and

lock

in

place.

(Scale still set

at

zero.)

6.

Place

the

trammel

bar

at

the

front

of

the

tires.

Adjust

the scale

end

so

that

the

pointers

line

up

with

the

scribe

marks.

7.

Read

toe-in

or

toe-out

from

the

scale. Scale

should

read

toe-in

1/16".

(Tolerance

t

1/16.)

8.

If

adjustment

is necessary,

loosen

the

tie-rod

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