Automobile Operation: Disassembling and Reassembling Brake Wheel Unit and Step-by-Step Procedure

Automobile Operation: Disassembling and Reassembling Brake Wheel Unit

 

Preventive maintenance of the braking system.so important in driving, makes it periodically necessary to take apart all the parts of the brake wheel units with the object of checking the state of these parts and for their subsequent cleaning and repair. In doing this operation the mechanic should confine himself strictly to the specifications laid down by the manufacturers.

 

METHOD OF EXECUTION

TO DISASSEMBLE BRAKE WHEEL UNIT

 

1st Step - Remove the wheels -.and drums thus:-

 

a) Position and raise the vehicle.

b) Remove the wheels.

c) Close the adjusters of the brake shoes and remove the drums (Fig. 1).

 

 

OBSERVATION

Avoid stepping on the brake pedal when the drums have been removed.

 

2nd Step - Remove the brake shoes thus: -

a) Remove the return springs of the brake shoes (fig. 2).

b) Remove the locks of the springs.

c) Push in the pistons of the brake cylinders with a spring clamp, (fig. 3).

d) Disconnect the control cable of the hand brake, by pressing the spring forward and lifting thè cable so as to unhook it.

e) Remove the brake shoes.

 

 

3rd Step - Remove the brake cylinders thus:-

a) Disconnect the lines and tubing’s.

b) Remove the securing screws and remove the cylinders.

 

SAFETY MEASURE

Avoid spilling the brake fluid on to the ground.

 

 

4th Step - Dismantle the brake cylinders thus: -

a) Remove the push rods and the dust covers.

b) Remove the pistons, rubbers and springs.

 

OBSERVATION

Repeat this step for each cylinder, placing the parts in separate containers so as to prevent mixing up.

 

5th Step - Clean the disassembled parts thus: -

 

a) Clean the parts of the cylinder with alcohol and a brush.

b) Dry them with compressed air.     

TO REASSEMBLE BRAKE WHEEL UNIT

 

1st Step - Inspect the dismounted parts thus:-

a) Make sure that the surfaces of the cylinders and pistons are free of scratches.

b) Check the play between pistons and cylinder with a feeler gauge according to manufacturer's specification,

 

OBSERVATION

If there are small scratches on the cylinders, polish them with fine water-proof paper.

 

2nd Step - Assemble the brake cylinders, thus:-

a) Lubricate the cylinders and other parts with the same brake fluid that is to be used in the system.

b) Replace the spring, the rubbers, pistons and dust covers (Fig. 5).

c) Use the spring clamp to hold the pistons and rubbers. 

 

3rd Step - Replace the wheel cylinders thus: -

 

a) Replace the cylinders on the brake backing plate, securing them with their screws.

b) Reconnect the lines and tubing’s.

 

4th Step - Replace the Brake Shoes, thus: -

 

a) Re-assemble the brake shoe unit, adjuster, and bottom spring, (fig. 6).

 

OBSERVATION

Lubricate the thread of the adjuster.

 

b) Replace the push rods of the brake shoe into the cylinder.

c) Replace the brake shoe unit on the plate, (fig. 7). 

 

OBSERVATION

Lubricate the sliding supports of the brake shoes.

 

d) Install the hand brake operating lever link with its spring and connect the control

cable to the operating lever.

e) Replace the brake shoe locks.

f) Replace the anchor pin plate and the retracting springs. (fig. 9).

g) Remove the spring clamp that was used to hold the brake cylinder pistons.

 

OBSERVATION

Avoid deforming the hooks of the spring or stretching them more than necessary to hook them.

 

 

5th Step - Replace the drums and wheels.

 

OBSERVATION

When replacing the drums, close the adjuster of the brake shoes.

 
6th Step - Adjust the brake shoes of the brake wheels’ thus:-

 

a) Open the adjuster until the wheel is locked.

b) Close the adjuster, until the wheel spins freely.

 

7th Step - Lower the vehicle and tighten the wheels again.

 

8th Step - Bleed the system.