Hubbed
Hubless-Vented
Solid
Composite
Vented
Some are directional
Composite -
Must be machined with adapter
- Strong when bolted against wheel
- Outside cast iron
- Inside stamped steel help fuel
economy
Coefficient
of Friction =
measurement of friction between 2 surfaces
Weight
transfer = shorter the
car, the more rate transfer we have
·
During
a panic stop, considered 1 g = about as fast as you can decelerate
·
Majority
at brake is at front Brake Biased
Rotor mic vs. regular mic differences slip-clutch
·
Pointed
anvil to get into grooves (keep
uniform measurements)
·
Starts
as .300 and goes to 1.300
·
Conventional
thimble has 25 marks, every revolution is .025
·
Never
store micrometer all the way closed
·
Operated
off a bolt and nut principle
DIAL INDICATOR
·
Always
be straight on to what you want to measure or perpendicular
·
Preload
dial indicator
SIU
Specs for rotor run out: .005 [rotor
run out]
·
Parallelism
(thickness variation) = .0005
·
Rotor
Taper = .002
Rotor runout:
·
If
hubless, reinstall lugnuts
·
If
tapered bearing (hubbed) - overtighten to compensate for lash
·
When done, readjust
·
Anymore
run out than .005 gives you a pulsating pedal
·
Loose
wheel bearings on disc brakes cause a low brake pedal
Looser it is, the lower the pedal
Rotor Taper measure at points A & B with
micrometer
Parallelism measure in six spots around the rotor
T.I.R. Total Indicated
·
There
could be a problem with the hub
We will hand torque all lug nuts
·
80-85
minimum rule of thumb
·
Aluminum
wheels need tighter torque
MEASUREMENTS
Dial
Indicator standard mic
·
Careful
when releasing pressure
·
On
drums, in, first out, last
·
Base
setting whatever inch
drum you have 11, 10, 9
·
And
then add dial indicator reading
·
Move
out 1/8 of an inch at a time 1/8 = .125
·
Looking
for highest reading on dial indicator
·
If
you have a metric drum convert 25.4 mm = 1 inch
·
What
if too large of drum? Gets bigger
during use
·
Gets
too thin wont dissipate heat warp/crack
·
The
bigger the diameter, the more leverage
·
More
braking for initial stop
·
QUESTION: What does maximum diameter found on the drum
mean?
1. The Maximum diameter that can be machined
to and still be put back into service.
2. The Discard or throw away diameter which
cannot be put into service.
·
10
drum 10.060 max. Diameter, 10.090 discard
·
Drum
mic calibration = at 0 dial indicator
(The lowest
reading of the dial indicator should be 0)
Drum Machining:
Scratch test make 2 marks, If marks are at the
same location (side by side), the mounting is
correct. If the
marks change when remounted, a mounting
problem exists.
WHEEL BEARINGS
2-styles seal, tapered. Tapered adjustable
·
Tapered
adjustable
·
Has
an outer race/cup and an inner cone (free to rotate)
·
Need
to be replaced as a unit
·
To
test
·
Roll
it to see if there is any roughness
·
Test
drive, lightly veer from left to right, if the noise increases, tapered
bearings will get louder when you load them up
·
Sealed
·
A
sealed bearing will get quieter when you lead them up
·
Jack
up back end ( or one wheel if open differential)
·
Run
it, do you hear noise?
·
Tapered
left, spin wheel, hard on bumper can feel growling
If you turn to
the left, you are loading the right.
Tapered: outer smaller, inner -
1. Take
dust cap off remover, channel lock, chisel, do not damage or crease.
2.
Remove cotter key
3.
Remove nut set on towel or paper
4.
Washer
5.
Inspect roller get rid of grease
·
must
get rid of all solvent because it breaks down the new grease packed it
·
do not dry with air so it spins fast!
Repack use proper grease by hand, forced all
through bearing.
Inner
bearing:
·
Must
remove outer cover to get to it
·
Wipe
with clean towel are there metal shavings
·
If
not, just repack, as it will push old out
·
Do
not mix, race and bearing area matched set
·
Tighten
bolt follow directions, lighten to
and then back off 1/2 a flat
·
Tighten
down back off, then hand tighten with wrench
Cotter key must not rub on dust cover!