Thread: Substitue for Emery Paper

The machine shop that machines the drums should do that for you

Sanding belt will be fine to remove the glaze.

Originally Posted by Lappa

Sanding belt will be fine to remove the glaze.

Thanks. The drums are fine, just need to remove the glaze by circular sandpaper movements as per the workshop manual.

Originally Posted by Kidbee

Thanks. The drums are fine, just need to remove the glaze by circular sandpaper movements as per the workshop manual.

The workshop manual is wrong, they should always be given a skim to remove the glaze and the shoes radius ground to the new diameter. Also never replace the shoes without replacing the cylinders as they will leak shortly afterwards. If a customer's car needed brake shoes it always got new cylinders or we didn't do the job and they went elsewhere. I will now wait for all the stories on how it was done and the cylinders did not leak.

Totally agree with Chris regarding the wheel cylinders. Always replace!

The new shoes are guaranteed to be of a different radius than the drums. In fact the drums may no longer perfectly circular. Really the drums must be machined to insure that they are perfectly round. At that time the new brake shoes are "Radius-d" to match the radius of the drums.

Also you MUST make sure that the shoes and drums are of the same radius. If they aren't of the same radius, the stopping power will be diminished. If the wheel cylinders aren't rebuilt, leaks and possible brake system failure is likely.

As the brakes are used and the shoes wear out, the pistons never return to their exact original position within the cylinder. Sludge and crud build up in back of the piston in the cylinder. When the new shoes are installed the piston is forced back into the original position. This can cause immediate failure or a failure later on, preferably after the warranty period.

Originally Posted by Lappa

Totally agree with Chris regarding the wheel cylinders. Always replace!

just to be clear, do you mean replacing the whole cylinder or just putting new piston caps & seals in.

TT

You could either replace the cylinder or rebuild the originals, i.e. clean, hone, replace seals and dust covers

Depending on the vehicle, new ones are usually pretty cheap these days. Re honing: cast iron - yes, as long as you don’t go oversize (will need oversize cups): Anodised alloy - do not hone: non anodised alloy, light hone only using 800 to 1000 grit wet and dry wrapped around hone legs.
Generally, by the time you hone and buy seals and dust boots it’s cheaper to buy new ones.

I agree song long as you can buy new items