MOT No. 29
Press the brake pedal with your hand.
The free play should be a maximum of ⅓ of the total pedal travel.
A longer pedal free play indicates that the brake pads have worn to a minimum thickness and should be replaced.
Or the parking brake is incorrectly adjusted.
Too long pedal travel can also be caused by jammed brake pads or a rusted brake caliper.
It is possible that air has entered the brake system.
Removing the brake drum
Remove one wheel bolt.
The brake drum can be removed without removing the wheel. In this case:
Raise the car from behind.
Rotate the rim or brake drum so that the bolt hole is at the top front of the vehicle.
Using a screwdriver, press the adjusting wedge up through the bolt hole - this will push the brake pads out.
Remove crown wheel cap (see fig. in chapter «Wheels and tires»).
Unbend and remove the safety pin in the wheel bearing.
Remove the crown lock, unscrew the hex nut, remove the thrust washer and the outer wheel bearing.
Remove brake drum.
When installing, be sure to adjust the play of the wheel bearing (see chapter «Wheel suspension and steering»).
Bring the pads to the brake drum by pressing the brake pedal hard once.
Hint: if the old car can't push the rusted adjusting wedge up, have an assistant depress the brake pedal while you push the wedge out. Then you should release the brake pedal and only now remove the screwdriver from the hole, otherwise the wedge will drop down again. Make sure that the pedal is depressed only if both brake drums are installed.
Checking the condition of the brake drums
The rubbing surface in the drum should be as smooth as possible.
If deep furrows or scratches are visible (due to worn out brake pads), the drum can be bored.
The inner diameter of the new brake drums is 230 mm.
After boring, the inner diameter must not exceed 231 mm, otherwise both brake drums must be replaced.
Removing the brake pads
Remove brake drum.
Press the spring plate of the brake shoe holder with pliers, turn it 90° (holding the mounting pin at the back of the shield,
so that it does not rotate with the shield) and remove them, then remove the springs.
Unhook the adjusting wedge return spring.
With the brake drum removed, we see the following elements in the rear wheel brake mechanism:
1 - front brake shoe;
2 - adjusting wedge;
3 - wheel brake cylinder;
4 - cable drive of the parking brake;
5 — the lever of inclusion of a parking brake;
6 - rear brake shoe.
Separate the brake shoe from the lower support and the piston of the brake cylinder.
Disconnect the parking brake cable from the removed shoes.
Remove return springs at top and bottom.
Pull the adjusting wedge out of the push rod.
Detach the main spring from the top of the pressure rod. If necessary, secure the pressure rod in a vise.
When assembling, secure the pressure bar in a vice.
Hook the main spring to the pressure rod and the brake shoe. How to install the spring is shown in the figure at the top of this and the following pages.
Install the brake shoe on the pressure rod, insert the adjusting wedge from above. Its protrusion is directed towards the brake pad.
Install the brake lever of the passive shoe into the protrusion of the pressure rod, attach the upper return spring.
Hook the parking brake cable, with the brake shoes not yet fixed, onto the parking brake lever.
Removing the drum brake cylinder
Remove brake drum.
Remove brake pads.
Unscrew the bleed valve.
Disconnect the brake hose. If you are not going to immediately install a new brake cylinder, you should depress the brake pedal and leave it in this position in order to prevent unnecessary loss of brake fluid.
Remove the two fixing bolts on the back of the drum brake shield and remove the brake cylinder.
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