RayTek AUTOPRO Manual De Instrucciones página 14

Brakes (Cont.)
systems and applies to vehicles with disc/disc,
drum/drum or disc/drum brake configuration.
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. Stop vehicle, place in Park (auto trans)
or neutral (manual trans) and set parking brake.
Using the IR thermometer, measure temperature of
front and rear brakes. See Figs. 2 & 3.
Fig. 2: Measuring Disc Brake
Temperatures
If temperature differential between front and
rear brakes is greater than 30°C (50°F), rear
brakes may not be working effectively. Check the
following:
n Front brake adjustment too tight
(drum brakes - front).
n Rear brake adjustment too loose
(drum brakes - rear).
n Emergency brake adjustment.
n Combination valve malfunction.
n Master cylinder malfunction (check for loss of
brake fluid without a visible fluid leak).
n Leaking calipers or wheel cylinders.
n Master cylinder overfilled.
n Brake line or hose restriction.
If temperature differential is less than 30°C
(50°F), or rear brake temperature is hotter than
front brakes, front brakes may not be working
effectively. Check the following:
0
n Front brake adjustment too loose
(drum brakes - front).
n Rear brake adjustment too tight
(drum brakes - rear).
n Emergency brake adjustment too tight.
n Combination valve malfunction.
n Master cylinder malfunction.
n Leaking calipers or wheel cylinders.
n Brake line or hose restriction.
Some vehicles also have a load-sensing valve near
the rear brakes. Check this valve for proper opera-
tion where applicable.
Fig. 3: Measuring Drum Brake
Temperatures
Diagonal Split Brake Systems
Diagonal split brake systems differ from front/rear
split systems in that each circuit of the master cyl-
inder operates one front brake and the diagonally
opposite rear brake. See Fig. 4.
As in front/rear split brake systems; diagonal
split brake systems front brakes will normally
have higher temperatures than rear brakes when
working properly. Normal temperature differential
between front and rear brakes is 30°C (50°F).
Diagonal split brake system symptoms are often
related with a brake pull. This is when the vehicle
pulls to left or right when the brakes are applied.
This procedure trouble shoots operation of the
diagonal split brake system and applies to vehicles
with disc/disc or disc/drum brake configuration.
To obtain an accurate temperature reading, test
drive vehicle in a low-traffic area, preferably on a
straight, level section of roadway. Operate