Lada Niva Manual - Maintenance
Page 20
Bleeding the Brake System
An increased travel and sponginess of the brake pedal manifest the presence of air in the
brake system which impairs considerably efficiency of the brakes. Evacuate air from the
system by bleeding in succession; the brake mechanism cylinders of the R.H. rear wheel, then
of the L.H. rear wheel, of the L.H. front wheel and, finally, of the R.H. front wheel through
the upper bleeder valves. In this way the first brake circuit will be bled. To repeat the
procedure for the second brake circuit, make use of the lower bleeder valves of the front
wheel brake mechanisms. It is allowed to start the bleeding procedure from the R.H. or L.H.
front wheel.
Do not jack up the car rear to exclude influence of the pressure regulator.
To perform bleeding, proceed as follows:
1. Unscrew the reservoir cap (Pig. 58) and add some fluid up to the normal level.
2. Remove the protective caps from bleeder valves 3 (Fig. 59) and 2 (Fig. 62) and clean the
latter of dirt and dust.
3. Fit a rubber hose on the bleeder valve head (the hose is available in the set of car
accessories) and dip the hose end into a clean transparent vessel, partly filled with brake
fluid.
4. Press the brake pedal sharply 3-5 times with an interval of 2-3 s and, holding the pedal in
the pressed down position, give the bleeder valve '/,-3/4 01 a turn out and keep pressing
down the brake pedal to force out the brake fluid together with air into the vessel. When
the brake pedal rests against the stop and escape of the brake fluid ceases, screw in the
bleeder valve. Repeat this operation until air bubbles cease to escape from the hose.
5. Keeping the brake pedal de- pressed, screw the bleeder valve all the way in and remove the
hose. Wipe the bleeder valve end dry and install the protective cap.
In the process of bleeding see that the fluid level in the reservoir is sufficient. The bleeding
over, restore the required maximum fluid level in the reservoir. The fluid discharged from the
brake system during the bleeding should not be reused.
Pressure Regulator
Every 30.000 Km check the pressure
regulator for serviceability, for which
purpose:
Fig 63. Brake hydraulic system.
1- brake master cylinder, 2- vacuum
booster, 3- pedal pull-back spring, 4- stop light switch, 5- thrust screw
nut, 6- stop light switch buffer, 7- pushrod, 8- brake pedal.
•
Place the car on a lift or an inspection pit;
•
Clean the regulator and its boot from dirt;
•
Carefully remove the boot, wipe off the
remaining grease, and clean the torsion
lever-to-regulator piston joint;
•
Ask an assistant to sharply depress the
brake pedal. With the pressure regulator
serviceable, the protruding portion of the
piston will move relative to the body, thus
twisting the torsion lever.
•
Repeat the operation two or three times and, having made sure that the pressure regulator
is serviceable, pack 5-6 g of fresh grease P~T-1 into the regulator, and put on the boot.
•
If the piston does not move relative to the body, apply to a service station.
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