How To Replace Vespa 10" Rear Brake Shoes
One of the common maintenence tasks on a vintage Vespa is brake replacement. The rear brakes are more prone to issues due to their proximity to the axle, oil, exhaust, etc. So let's see how it is done!
Before You Get Started
As with every project, get all of your parts together first. Read through these directions to get a sense of what parts you may need, and then buy them. This project requires your normal hand tools. The special tools you will need are either an impact wrench or a breaker bar, and a torque wrench. As discussed below, you will also need a respirator rated for asbestos.
WARNING: Original Vespa brakes almost certainly contained asbestos in the linings. Asbestos is really bad stuff. As the linings wear, they generally give off "brake dust", which will also almost certainly contain asbestos. You do not want to breathe asbestos. Before you do any work on your brakes, do yourself a favor, and buy a respirator which is rated for asbestos. They are not expensive. Do it now. You will also want to have brake cleaner handy, and some shop rags. If you see any brake dust, you will want to soak the rags in the cleaner, and wipe up the dust with it. Wet dust does not fly around, and thus, you won't breathe it in. When you are done with the job, throw away the rags. Do not re-use them.
First, remove the battery side cowl, and then the spare tire. This will allow easier access to the rear hub.
Removing the Rear Hub
Now, we turn our attention to the rear hub. Pull off the chrome cover for the rear hub nut. This will reveal the castellated nut, with a cotter pin locking it in place. Remove the cotter pin. The rear nut will be hard to get off. If you have access to an impact wrench, you'll want to use that. If you don't, you'll need to find a friend to help you. Have your friend stomp on the rear brake. Then, using a breaker bar (a long pipe attached to the end of your rachet), remove the nut. With the nut off, pull the spacer washer off the axle. Then, pull the rear hub off. At this point, inspect the rear hub. If it looks damaged or worn, you'll want to replace it.
Removing the Brake Shoes
Here is a view of the rear brake area with the hub off. We can see the cause of the problem with the brakes on this scooter clearly. Oil leaked past the rear axle seal and into the brake hub area. Oil does not help your brakes work! With oil the brake area, it means these shoes are toast, so we are going to replace them.
Start by removing the shoes. First, remove the two small retaining clips at the front brake posts. Then, pivot the brake actuator at the rear of the brake shoes by pressing the rear brake pedal. Then, get a flat blade screw driver into the space between the shoe and the brake cam, as shown in the picture above. Push up on the shoe to get it away from the cam, and then, using another screw driver, slowly work the shoe off the set pin at the front. You need to make sure to work both sides of the shoe evenly so it doesn't bind on the front pin. The whole thing will eventually pop off.
The New Brake Shoes
With the shoes off, you want to prepare your new shoes. The picture above shows them with the spring, which I removed, and cleaned, from the old shoes. Next, not shown, I cleaned the whole brake area with brake cleaner and rags.
Putting on the New Brake Shoes
Next, we put on the new shoes. First, place one of the shoes on the front pin, and the rear cam.
Then, take the second pin, and place it just barely on the outside edge of the cam. Using the cam as a pivot, swing the shoe around, and hook it on the front pin. When you have both sides of the shoe even, and barely on the pin and cam, lightly tap the shoe into place.
When you are done, it will look like this. Then, put both of the small retaining clips on the front brake pins. At this point, move the rear brake pedal to make sure everything works as it should. Then, loosen the nut on the rear brake cable so that the brake shoes are in a "neutral position". You will adjust the brake cable later. However, if the brake cable is too tight at this point, the rear hub won't fit over the shoes.
Next, we place the rear hub over the shoes and onto the axle. Then, put the spacer washer and castleated nut onto the axle. Tighten the nut using a torque wrench to 500-550 kg/m. You want to make sure that when the nut is tightened in the correct range, that one of the "windows" on the axle line up with a slot on the nut. When they are lined up, slide your cotter pin through the nut, and then peen it over the nut. The cotter pin locks the nut so that if it loosens somehow, it won't fall off the axle. DO NOT omit the cotter pin, it is a crucial safety component.
With the hub on, and locked into place, it is time to adjust the rear brake cable. Using your "third hand tool", pull the slack out of the cable. Then adjust the cable so that the shoes are just short of engaging the brakes. Then tighten the screw on the rear brake actuating arm. Hook the free end of the cable into its keeper on the actuating arm. Test the brake by spinning the wheel and pressing the brake pedal. You should hear no scraping, and the brakes should stop the hub easily. Once you are satisfied that you have adjusted the cable, and everything is working as it should, put the rear wheel on the hub. Then put the spare back on, and then the battery-side cowl. You're done!