How to Machine Brake Drums

January 27, 2012

The process you follow when you machine brake drums, also known as brake drum turning or adjusting, is one of the most important maintenance measures that you should take when caring for a vehicle. The brake drums are an integral part of the braking system on any car equipped with them, and they are responsible for keeping the braking system working properly. Without adequately functioning brake drums, you'll find that your vehicle's brakes will respond slowly and differently from normal. In severe cases, the brake drums will not work at all. In order to avoid putting yourself, your passengers and anyone else who you share the road with in danger due to your faulty brakes, it's important to learn about when and how to machine your brake drums and the rest of the braking system in your car.

Step 1 - Collect the Necessary Tools and Materials

You'll need the following tools and materials in order to adequately machine your brake drums:

  • Blocks of wood or wheel chocks to prevent the wheels from moving
  • Car jack
  • Axle stands (at least 2)
  • Long metal rod
  • Car grease and a large rag
  • Screwdrivers of various sizes, flat headed

Step 2 - Block the Wheels and Jack Up the Car

Carefully place the wheel blocks such that the wheels of your vehicle will not be able to roll and move under any circumstances. Once you're satisfied that the vehicle is stationary, use the car jack to carefully elevate the rear of the vehicle. You'll want to lift it up until the car is high enough off of the ground that you can comfortably work underneath it without being restricted. Mount the car up on the axle stands and be careful that the vehicle is completely secure before attempting to work.

Step 3 - Remove the Wheel Drums

The wheel drums themselves are attached to the adjuster in the braking system. The braking drums are large blocks that you'll need to remove in order to have a professional machine shop work on them and cut them down to the appropriate size. Remove the cap on the brake drum adjuster and use the metal rod to carefully remove the brake drums themselves. If they're stuck, unscrew the attaching screws that connect the two components using your screwdrivers.

Step 4 - Take the Drums to a Machine Shop

Once you've removed the brake drums, you'll need to have them turned. Turning a brake drum involves placing it on a lathe and carefully shaving off a small amount of the drum in order to adjust the size until it's perfectly even and appropriate for your vehicle brake system. Unless you have a garage sized lathe in your home, you'll have to take the vehicle to an auto body shop in order to have them turned. Brake drum turning can be done at Pep Boys, Kragan or any number of local auto body shops in a few minutes and for a small charge.

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