1987 NISSAN PULSAR air bleeding

Brakes 173
Inspect the handbrake cable for chafing or fraying.
(4) Seized handbrake cables: Renew the hand-
brake cables.

NOTE: Raise the vehicle and spin the
wheels one at a time to check for binding. If
the wheels are not binding, have an assistant
apply and release the brakes. Check if the
brakes release immediately. A clogged mas-
ter cylinder port will cause binding on the
two wheels fed by that particular circuit
from the master cylinder. Open the bleeder
valve on one of the o ffending wheels to check
if pressure build up is the cause of the
binding. A seized handbrake cable will usu-
ally cause binding on a rear wheel. Discon-
nect the handbrake cable and check if the
wheel will then turn freely.

LOW SPONGY BRAKE PEDAL
(1) Incorrectly adjusted brake shoes: Check and
adjust the brake shoes.


(2) Insufficient fluid in the system: Check for
leaks, replenish the fluid to the specified level and
bleed the hydraulic system.
(3) Air in the brake hydraulic system: Bleed the
hydraulic system. (4) Master cylinder faulty: Repair or renew as
necessary.
NOTE: A spongy brake pedal in most cases
is caused by air in the hydraulic system. For
air to enter the system one or more of the
sealing rubbers or brake lines must be
sucking in air. Always rectify the cause of
the trouble before bleeding the hydraulic
system. Faulty components usually show up
as fluid leakage.

BRAKES LOCK ON APPLICATION
(1) Gummy linings or brake pads due to oil or
fluid contamination: Renew the linings or brake pads
and rectify the source of contamination. (2) Scored or eccentric brake drum or warped
disc: Check and machine or renew the drum or disc as
necessary.
(3) Incorrect or distorted linings or disc pads:
Check and renew as necessary. (4) Brake servo unit faulty: Repair or renew the
brake servo unit. (5) Broken or stretched brake shoe return
springs: Check and renew th e faulty brake springs.
(6) Faulty brake pressure proportioning valve:
Renew the brake pressure proportioning valve.
NOTE: If this condition arises, remove all
the wheels and check the condition of the
friction material for oil contamination and
excessive wear. Check the shoe return
springs for stretching by comparing their
free length with new sp rings. An eccentric-
brake drum or warped disc will be indicated
by pulsating of the brake pedal when the
brakes are lightly applied.

BRAKE PEDAL PULSATES
(1) Eccentric brake drums or warped disc: Check
and machine or renew the drum or disc as required.
(2) Loose or worn hub bearings: Renew the hub
bearings as necessary.
NOTE: Brake drums or discs that are run-
ning out must be machined. This job is best
entrusted to a brake specialist who will also
be able to determine if a new disc or drum
needs to be installed.

BRAKE FADE
(1) Incorrect shoe adjustment: Check and adjust
the shoe to drum clearance. (2) Eccentric brake drum: Check and machine or
renew the brake drum.

Check the brake hoses for deterioration, chafing and
leaks.

188 Brakes

Illustration showing the brake pedal adjustments. Di-
mension H = brake pedal height, Dimension C = stop
lamp switch clearance, Dimension F - brake pedal free
play.
TO ADJUST STOP LAMP SWITCH
(1) Loosen the stop lamp switch locknut and
disconnect the wiring from the switch.
(2) Adjust the stop lamp switch to achieve a
clearance of 0.3-1.0 mm between the pedal stop and
the threaded end of the switch. (3) Tighten the locknut and connect the wiring
to the switch. Ensure that the stop lamps are off when
the pedal is released.
(4) Ensure that the pedal free play is 1.0-3.00
mm after adjustments have been completed.
11. HYDRAULIC SYSTEM

TO BLEED
Bleeding the hydraulic system should only be
necessary when some portion of the hydraulic system
has been disconnected or fluid has been drained,
allowing air to enter the system.

The brake fluid in the hydraulic system should be
changed every 30 000 km or 18 months. The proce-
dure for changing the brake fluid and bleeding the
hydraulic system are simila r with attention to the
notes in the text.

There are four points in the system where bleeder
valves are installed, one on each front caliper and one
on each rear wheel cylinder or rear caliper.

14. Fill the fluid reservoir with clean hydraulic
brake fluid and maintain at least one third full
throughout the entire operation. 15. Attach a transparent hose to the bleeder
valve on the left rear cali per and immerse the other
Bleeding the right hand rear brake caliper.
end of the hose in a small amount of clean brake fluid
contained in a clean glass jar held higher than the
bleeder valve.

14. Unscrew the bleeder valve one
complete turn.
15. Have an assistant depress the brake
pedal slowly to the full extent of its travel. Close
the bleeder valve and allow the brake pedal to
r e t u r n w i t h o u t assistance. 16. Repeat operations (3) and (4) until
a con stant stream of fluid, without any air
bubbles, is being discharged into the gl ass jar,
hold the brake pedal down and tighten the
bleeder valve.
Bleeding the right hand front brake caliper.

Brakes 189
NOTE: If changing the brake fluid, continue to be made. Always use new brake fluid for
bleeding the system until clean new fluid t opping up the reservoir.
flows from the bleeder hose. (6) Carry out the operation on the right front,
Do not allow the fluid level in the reser- right rear, right rear and left front brake in that order.
voir to fall below the one third full level at (7) Replenish the reservoir with the specified
any time during the operation or air will brake fluid to the indicated level and install the
enter the system and a fresh start will have reservoir cap.