How to check and adjust the gap of brake drum shoe of large imported vehicle?
TIME：2020.01.20
How to check and adjust the gap of brake drum shoe of large imported vehicle? All vehicles (motor vehicles, non-motor vehicles, pneumatic brakes, hydraulic brakes, mechanical brakes, disc brakes, hub brakes, large cars, small cars, etc.) have their own braking systems and devices, how to check and adjust the gap of brake drum shoe of large imported vehicle? Check the thickness of the brake lining first. When the thickness of the friction plate is less than the standard, the friction plate has reached the wear limit (for example, the thickness of the friction plate of Setra 1291 is 6 mm) , the friction plate should be replaced first. Check brake clearance shall be made when the brake drum is in a cold state. Support the inspected wheel so that the wheel can turn freely. Press both hands hard on the outside of the tire to check for loose hub bearings. If it is loose, it should be adjusted. Otherwise, the brake clearance can not be adjusted correctly. The clearance between the brake drum and the brake shoes can be measured with a plug gauge while checking the brake pads. If the clearance exceeds the standard, it shall be adjusted. According to its structure, the large-scale imported wheel brake shoe clearance adjusting device can be divided into cam type and camshaft adjusting arm type (for all-air brake vehicle) . (1) adjustment of imported CAM brake. The use of cam-type brakes imported more models, such as Mitsubishi, Isuzu and other models of the wheel brake. Remove the dust plug from the brake adjustment hole and turn the adjustment Cam in the direction indicated by the Arrow until it is no longer in a position to rotate. Then turn the cam back slightly in the opposite direction. Insert the plug gauge with the same clearance as the shoe into the depth of the shoe and brake drum through the adjustment hole. Then, twist the adjusting cam to reduce the clearance to the point where the plug plug can be pulled out with a little manual force. Turn the wheel, the wheel should be able to turn freely, no friction sound. Note that some wheels have two adjustment cams and adjustment holes, so adjust the brake shoe clearance on the other side in the same way. After adjusting the clearance, install the dust plug of the adjusting hole. Adjust the brakes on the other wheels in the same way. Vehicles fitted with shoe wear indicators should check the position indicated by the indicators after brake clearance adjustment. If the indicator is located outside the "START" to "END " range, the shoes are worn beyond the limit of use and the friction pads should be replaced. After the brake clearance adjustment, start the car, slow start the car, test the brake effect, check whether there is no bias brake or other phenomenon. If there is any abnormality, adjust the brake again. (2) adjusting arm brake of imported vehicle. Imported cars with adjustable arm brakes (such as Setra 1291) use full pneumatic braking systems, and wheels have adjustable arm brakes. Adjust the work as follows: First in the wheel pad good block, supporting the inspected wheel (such as the rear wheel, should release the hand brake) , make sure that the wheel hub bearing is not loose. Start the engine so that the Compressed air pressure rises above normal operating pressure, and then, keep the engine spinning (a non-spring energy storage brake chamber does not do this) . Fold down the dust plug of the inspection hole to check the wear of the friction plate from the inspection hole. If the friction plate wear to the use limit, should replace the friction plate. After inspection, dust plug of inspection hole should be installed. The worm shaft of the brake adjuster arm of the lighter rotates the brake cam shaft to the point where it can no longer rotate, so that the brake push rod is fully extended (i. e. the brake shoes are pressed against the drum) . From this position on the front wheel, turn the adjusting arm worm shaft back 3 ~ 4 Clicks; from this position on the rear wheel, turn the adjusting arm worm shaft back 4 ~ 5 clicks. Measure the working stroke of the push rod of the Brake Chamber. If the working stroke does not meet the requirement, adjust the worm shaft of the adjusting arm to meet the requirement and adjust other wheels in the same way. After adjusting the wheel brake, start the car at a speed of 30 km / h, test the braking effect of the brake, check whether there are other abnormal phenomena such as bias brake, malfunctions or excessive braking distance. If there is an exception, the brake adjustment should be re-checked. For models with Spring loaded brakes, make sure that the Compressed air pressure is kept above the normal working pressure when adjusting the brake clearance. If the pressure is low, the Spring Energy Storage Brake Piston is not in the normal release parking brake position, it can not be accurately adjusted.
