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Wednesday, March 30, 2011




            To adjustment of brake and clutch as per specification.


            Tool set.


            Three wheelers use hydraulic operated foot brake on the two rear wheels with an additional hand brake mechanically operated on the front wheel.
In hydraulic brakes, care must be taken that not even small quantities of air enter in to the braking system. The air being compressible, it gets compressed when the brake pedal is pressed. The result is that fluid pressure is not transmitted to the brakes. Which, as a consequence, are not actuated.
Due to the continuous use of the brakes, wear take place of the brake lining, linkage etc., which necessitate periodic inspection of the braking system and to make suitable adjustment. The brake adjustments can be broadly divided in to two types, viz, the minor and major adjustments.
            Minor adjustment mainly includes the adjustment of brake shoes to compensate lining wear and is done without removing the wheels. A major adjustment on the other hand, has to be done after installation of new shoes or relining the old shoes.


            The procedure of driving air out of the braking system is called bleeding. A special bleeding valve is provided for this purpose on the back plate. For bleeding, the master cylinder is topped up completely with the brake fluid and a pipe is connected to the bleeding valve. The other end of this pipe is dipped in the brake fluid contained in some jar. One person sits on the driver’s seat and presses the brake pedal, after which the bleeder valve is opened by the second person, when some air bubbles will come out of the pipe and escape through the brake fluid in to the atmosphere.
The bleeder valve is now closed and the brake pedal released and pressed once more after which the bleeder valve is opened again when some more air bubbles will come out. This procedure is repeated till on pressing the brake pedal, no more air bubbles are noted. Now with the pedal in the pressed position in the bleeder valve is closed.
To perform minor adjustment, on turning the adjustment nut the cam is also turned. This cam is fitted on the brake shoe and the adjusting nut is provided on the back plate. Turning this nut with spanner in the clockwise direction causes the shoes move closer to the brake drum.
            To perform major adjustment, remove all brake drums and inspect linings and drums. If the drums are worn out, turn them in case the damage is with in limits or else replace them. In case of linings having reached upto within 1mm of rivet heads, remove the same and reinstall the new ones.


            Clutch assembly is fitted between engine and gearbox. The purpose of the clutch assembly to transmit power of the engine to the rest of the transmission system, by disconnecting & connecting the power is required.


            The only adjustment required in a clutch is of the free lever play, which is necessitated on account of wear of the friction lining due to continuous use or with the wear of the throw out bearing carbon ring due to the habit of the driver to press his hand always on the clutch lever. The wear of the friction lining decreases the free lever play. An adjustment nut is provided at the lower end of the clutch lever. To slacken the lock nut first, make the desired adjustment with the adjusting nut and retighten the lock nut.


            Thus the adjustment of brake and clutch as per specification is performed.


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