Cooling System - RayTek AUTOPRO Manual De Instrucciones

Brakes (Cont.)
vehicle to 50 KM/H (30 MPH) and bring to a
complete stop 5 times. Stop vehicle, place in
Park (auto trans) or neutral (manual trans) and
set parking brake. Using the IR thermometer,
measure temperature of each front and each rear
brake. See Figs. 2 & 3. If the temperature reading
of one brake on the front of the vehicle is 3°C
(5°F) greater than the other front brake and the
diagonally opposite brake on the rear is also 3°C
(5°F) greater than the other rear brake, check for
the following:
n Master cylinder malfunction (check for loss of
brake fluid without a visible fluid leak).
n Master cylinder overfilled.
n Leaking calipers or wheel cylinders.
n Brake line restriction.
n Combination valve malfunction.
Fig. 4: Diagonal Split Brake System
Some vehicles also have a load-sensing valve near
the rear brakes. Check this valve for proper opera-
tion where applicable. If temperature differential is
greater than 3°C (5°F) only between the two front
brakes or the two rear brakes, check for conditions
associated with brake drag at one or more brakes.
Brake Drag/Pull (Left/Right)
Vehicle may pull to one side when brakes are
applied. One wheel may lock up under braking.
Uneven brake pad/shoe wear or glazed surface
may accompany condition. Heat damage to ro-
tor/drum may also exist. This procedure applies to
vehicles with disc/disc, drum/drum or disc/drum
brake configuration and also to front/rear and
diagonal split brake systems.
To obtain an accurate temperature reading, test-
drive vehicle in a low-traffic area, preferably on a
straight, level section of roadway. Operate vehicle
to 50 KM/H (30 MPH) and bring to a complete
stop 5 times. Make sure brake symptom is
duplicated. Stop vehicle, place in Park (auto trans)
or neutral (manual trans) and set parking brake.
Using the IR thermometer, measure temperature
of all brake rotors/drums. See Figs. 2 & 3. If tem-
perature differential of one brake is greater than
3°C (5°F) compared to the other brake on the
same axle, check for the following at all brakes:
n Binding caliper hardware (disc brakes).
n Frozen caliper (disc brakes).
n Leaking calipers or wheel cylinders.
n Broken, loose or missing brake hardware.
n Brake adjustment (drum brakes).
n Worn or damaged backing plates
(drum brakes).
n Wheel bearing adjustment.
n Leaking bearing or axle seals
(contaminated pads/shoes).
n Brake hose restriction.
On drum brakes, check that automatic brake ad-
justers operate properly. If temperature differential
between brakes is small or non-existent, worn
suspension components or alignment of vehicle
may be causing pull.

Cooling System

WARNING: Engine coolant can
reach temperatures exceeding
125°C (260°F). Allow engine to
cool before performing repairs on
cooling system or serious injury
may occur.
Each vehicle has its own optimum operating
temperature and a threshold beyond that to allow
vehicle operation without causing damage to
engine components. A cooling system may be
operating fine and have no visible signs of trouble,