Bearings, Bushings, CV Joints
& Universal Joints (Cont.)
NOTE: It is advised to check all
wheel bearings/hubs at the same
time to ensure all are in good
working order.
On other items such as alternator bearings, dif-
ferential pinion bearings or distributor bushings
that do not have a like component to compare
temperature readings measure temperature of
component away from bearing/bushing area. Then
measure bearing/bushing area. When operat-
ing properly, temperature should not change
significantly between the component and the bear-
ing/bushing area. If temperature increases at the
bearing/bushing area, inspect the bearing/bushing
and repair as necessary. On components such as
alternators, check for brown residue expelling from
bearings indicating bearing deterioration.
CV Joints & Universal Joints
CV joints and universal joints operate typically the
same as bearings. Lubrication and clearance are
key to proper operation. On a CV joint, a noise
or symptom is usually not heard until damage is
done. On a universal joint, often a squeak or a
vibration will indicate a marginal component. To
prevent this type of damage, whenever possible,
perform a thorough visual inspection to check for
damaged/torn boots or leaking seals.
To trouble shoot CV joints and universal joints,
test-drive vehicle a short distance. Stop vehicle,
place in Park (auto trans) or neutral (manual trans)
and set parking brake.
Using the IR thermometer, measure temperatures
at all CV joints or universal joints. The CV joint
or universal joint with excessive temperature as
compared to other CV/universal joints will indicate
potential bearing failure. Remove, inspect and
repair as necessary.
Brakes
Familiarity with the different types of braking
systems can aid in choosing the correct path of
diagnosis. High temperature at one brake does not
mean that is the brake with the problem. If another
brake is not operating properly, then the brake that
is hotter may be having to work harder to stop the
vehicle. See appropriate service for information to
verify type of braking system for vehicle.
NOTE: Before trouble shooting
brakes, ensure all tires are prop-
erly inflated to manufacturer's
specification. Ensure tire size on
vehicle is the same across the
front or rear and that bias-ply and
radial tires are not mixed.
CAUTION: Both front or rear
brakes should be serviced at the
same time to ensure brakes are at
optimum operating condition.
Front/Rear Split Brake
Systems
On vehicles equipped with front/rear split brake
systems, each circuit of the master cylinder oper-
ates either the front or rear brakes.
See Fig 1.
Fig. 1: Front/Rear Split Brake System
The front brakes will normally have higher tem-
peratures than rear brakes when working properly.
Normal temperature differential between front and
rear brakes is 30°C (50°F). This procedure checks
operation of front and rear brakes on these