The car has two independent braking systems: service and parking
The working brake system is hydraulic, dual-circuit (divided into front and rear circuits), with a vacuum booster, pressure regulator and an indicator of insufficient brake fluid level in the reservoir.
If one of the circuits of the brake system fails, the second circuit provides braking of the car, albeit with less efficiency.
The brake mechanisms of the front wheels are disc, with a single-piston floating caliper (when braking, the piston presses the inner pad against the disc, and the caliper, moving in the opposite direction, presses the outer pad).
The minimum allowable thickness of the front brake pads when worn is 3 mm.
The discs are ventilated, mounted on the hubs and attached to them with wheel bolts.
The minimum allowable disc thickness when worn is 19 mm. The bracket is attached with two bolts to the steering knuckle.
The brake cylinder is made in the caliper body; on the outside, it is covered with a rubber boot (dust boot) to protect it from dirt.
Inside the cylinder there is a groove into which an o-ring (cuff) is inserted.
When the piston moves out of the cylinder during braking, this ring twists slightly and, after braking, tends to return the piston to its original position.
This maintains a constant minimum clearance between discs and brake pads. The cylinder has a bleed valve.
Brake mechanisms of the rear wheels are drum, with two-piston wheel cylinders with automatic adjustment of the gap between the pads and the drum.
Thrust rings are inserted into the cylinder with an interference fit, limiting the free travel of the pistons (after braking), thereby maintaining a constant gap between the pads and the drum.
As the pads wear, the rings move by the amount of wear.
In the lower hole of the brake pads there are eccentrics for adjusting the position of the pads after replacing them.
The minimum allowable thickness of the rear brake pads when worn is 1 mm.
Maximum allowable inner diameter of the brake drum is 283 mm.
The main brake cylinder is attached to the vacuum booster housing with two studs.
A translucent polyethylene brake reservoir is inserted into the holes in the upper part of the cylinder with a sensor for insufficient fluid level (in the reservoir cap).
A plug is screwed into the front of the cylinder (along the direction of the car), which serves as a stop for the return spring and is sealed with a copper gasket.
Pistons in the master cylinder are arranged in series, the one closest to the vacuum booster actuates the rear brakes, the other piston - the front.
The sealing rubber rings (cuffs) of the main brake cylinder are not symmetrical in cross section, so it is important to orient them correctly during assembly.
When disassembling the cylinder, it is recommended to replace the cuffs, regardless of their condition.
When installing the master cylinder on a vehicle, check the gap (1.35–1.65 mm) between the end surface of the vacuum booster housing and the adjusting bolt.
If the gap is different from the specified, unscrew the lock nut and turn the adjusting bolt to achieve the desired gap, then tighten the lock nut.
The vacuum booster is located between the pedal assembly and the main brake cylinder and is attached to the bracket with four studs.
The amplifier is of a non-separable design; in case of failure, it is replaced.
The simplest check of its serviceability is as follows: on a car with the engine turned off, press the brake pedal several times and, keeping the pedal depressed, start the engine.
With a good booster, after starting the engine, the pedal should “go” forward.
Failure or insufficient efficiency of the vacuum booster may be caused by a leak in the suction hose from the intake manifold.
The pressure regulator is bolted to a bracket at the rear of the body with two bolts.
It prevents earlier blocking of the rear wheels in relation to the front ones, which increases the directional stability of the car when braking.
Responding through the load spring to the loading of the rear axle, it limits the fluid pressure in the rear brake circuit. The regulator is not repairable - in case of failure it is replaced.
After replacing the adjuster or elements of the rear suspension, it is necessary to re-adjust the position of the load spring relative to the rear axle.
Parking brake system drive - mechanical, cable, on the rear wheels.
It consists of a lever (with a handle and a locking mechanism), an intermediate lever and its rod, an equalizer and its rod, cables, a drive lever with a rod in the rear brake mechanismx.
The free play of the drive arm is adjusted by the eccentric on the rear block, and the tension of the cables is adjusted by the adjusting nut on the equalizer rod
What are the malfunctions of the brakes of the GAZ-3110 car:
- - increased brake pedal travel;
- - the rear brake drum is heated;
- - spontaneous braking of the car;
- - non-simultaneous operation of the brake mechanisms of one axis;
- - excessive effort when pressing the pedal;
- - weak action of the parking brake actuator.
Let's take a closer look at what causes these problems:
Increased brake pedal travel
Leakage of brake fluid from the hydraulic drive of the brake system - Identify the cause of leakage and eliminate by tightening the threaded connections or replace damaged parts. Bleed the brake system
Defective cuffs of the main brake cylinder - Replace defective cuffs
Presence of air in the brake system due to the formation of an emulsion (brake overheating) - Change the brake fluid and bleed the brake system
Wear of the friction linings of the brake pads of the front and rear brakes. The remaining thickness of the pad linings is less than the limit values - Replace the brake pads
The rear brake drum heats up due to spontaneous braking of the wheel
Loose or broken shoe return spring - Replace return spring
There is no guaranteed gap between the friction linings of the brake pads and the working surface of the brake drum - Adjust the parking brake drive
The drum of the front brake mechanism is heating up due to spontaneous braking of the wheel
Piston jamming due to contamination or corrosion in the caliper cylinder - Clean the cylinder and piston of dirt or corrosion. If necessary, replace the bracket body assembly
Spontaneous vehicle braking
Incorrect adjustment of the vacuum booster - Adjust the vacuum booster
The hole in the reservoir cap of the master cylinder is clogged - Clean the hole
Incomplete return of the brake pedal after removing the load from it - Clean the pedal assembly from dust and dirt. Check plastic bushings and return spring and replace if necessary
Swollen cuffs of the main brake cylinder or wheel cylinders - Replace defective cuffs. Bleed the brake system, filling it with the recommended brake fluid
Compensation holes of the master cylinder clogged - Clean the compensation holes
Non-simultaneous operation of the brake mechanisms of one axle (the car pulls to the side when braking)
Oiling the friction linings of the brake mechanisms - Eliminate the causes of oil entering the brake mechanism.
Wash or replace oily pads
Seizures on the working surface of the rear brake drum - Clean the damaged areas. If necessary, bore, grind or replace the drum
Pressure regulator set incorrectly. Rear wheels lock before front - Adjust pressure regulator
Braking requires excessive force when pressing the pedal
Faulty brake booster - Replace vacuum booster
Piston stuck in cylinder due to contamination or corrosion in caliper cylinder - Clean the cylinder and piston of dirt or corrosion. If necessary, replace the bracket body assembly
Oiling the working surfaces of the brake mechanism - Eliminate the causes of oil getting into the brake mechanism. Rinse or replace oily pads
Poor parking brake action
Rear brake pad wear - Adjust parking brake actuator
Pulling out the parking brake cables - Adjust the tension of the cables. Replace cables if necessary