Take out the rotor arm and the protective cover if fitted. Next remove the circlip for the pull rod from the vacuum unit and remove the unit. Mark the position of the spring clips for the distributor cap to save trouble on the assembly and remove them. Remove the terminal from the low tension lead and the condenser, remembering that your distributor may be different to the example but the principle is the same. The terminal is screwed through to the breaker plate and has to be removed before letting go of it. With the low tension terminal removed, pull out the breaker plate to expose the centrifugal advance mechanism. The breaker cam is free to move with respect to the distributor driveshaft and has an integral plate with projections which engage with two small weights attached to the top of the distributor shaft. As the distributor shaft turns, the weights fly outwards under centrifugal force and advance the ignition by advancing the distributor cam. Small springs are used to provide necessary opposition to the weights, and great care should be taken not to distort them when removing them. These springs may not be identical and therefore it is important to be aware of their location and have the distributor marked accordingly if required. If replacement is required, make sure the correct ones are obtained for your distributor. After down the springs mark the cam and distributor shaft for proper reassembly. Hold the cam in a vice with protecting jaws, then tap the housing to release the circlip holding the cam to the driveshaft and then tap the distributor housing to release the breaker cam held by a clip. Remove the cam from the shaft along with the lubricating wick, clip and washer. Undo the screws to extract the contact device if fitted, then remove the resilient ring and mark the shaft and driving collar so that it is properly reassembled. Drive out the pin and take the collar off the shaft. Carefully remove the shaft from the housing being careful not to lose any spacing washers, and remove the spring clips holding the centrifugal weights to the shaft and then the weights.