GM 88957254
Brake Drum

Currently performing routine brake system maintenance does not require drum refinishing until at least one of these conditions exists: extreme corrosion, pitting, cracking, heat spots, severe bluing discoloration, or scoring beyond maximum specification or radial runout beyond maximum specification. Check brake drums for these conditions before measuring their diameter when you remove tire and wheel assemblies. The J 41013 Rotor/Drum Flange Resurfacing Kit removes all corrosion from the brake drum flange before you follow the manufacturer's instructions to mount the brake drum on the lathe by ensuring vibration dampening attachments are properly installed. Check the witness mark while operating the lathe by placing the cutting tool against the brake drum friction surface. A properly mounted drum will show witness marks that extend for at least three-quarters of its surface area. The drum refinish process should follow lathe manufacturer guidance while you inspect each cut for diameter deviations and must replace the drum if refinishing extends the drum beyond specified tolerances. Use the specified speeds for your refinishing project when working on non-directional surfaces and use 120 grit aluminum oxide sandpaper if you have a non-directional finishing tool or 150 grit aluminum oxide sandpaper with a sanding block as an alternative when no tool is available. Wipe friction surfaces using denatured alcohol or equivalent brake cleaner after you apply the finish to them. Clear all remaining brake drum from the lathe machine then clean the wheel bearing flange with the J 42450-A Hub Cleaning Kit because not doing so may create lateral runout and brake system pulsation.

You must raise the vehicle properly to replace the Brake Drum. Record where the wheel connects to the axle flange before taking off the tire and the wheel. After you mark the drum position relative to the axle flange you can start taking off the Brake Drum. To solve the removal problem start with the retainer clip first then activate the parking brake control and shift the Parking Brake Cable's position away from the drum. Pull off the backing plate access hole plug and use a multi-purpose tool to turn the adjusting screw counterclockwise. Close back the access opening plug to defend the Brake Drum before placing lubricant along the drum pilot hole thread. Put the drum in place by matching the removal marks and put on the tire and wheel afterward. Press the brake pedal three times gently to let the pads contact the drum before putting the car on the ground.

Start your work to replace the Brake Drum by lifting and properly positioning the vehicle under adequate support. Take off the rear wheel unit but handle everything with care to keep the splash shield and backing plate straight as damages can cause brake buzz and pulsation. Next unfasten the brake assembly. The process starts with adjusting drum brakes before installing the Brake Drum and placing the wheel set onto the rear section. Lower the car after pressing the brakes three times to let the brake shoes touch the drum.

Service and repair of brake drums need the J 41013 Rotor/Drum Flange Resurfacing Kit with J 42450-A Hub Cleaning Kit. You should refinish brake drums only if you see signs of extreme rusting, damage spots, broken areas, intense discoloration from heat or if the brake drum wears past standard specification levels or runs out of line more than permitted. Check the brake drum surface for damage and measure its size when you take off all wheel components. Use the J 41013 to wipe off drum corrosion before setting up the brake drum on the lathe as prescribed by the manufacturer. Make sure vibration dampening hardware stays fixed during installation. Test the brake drum mounting accuracy by running the lathe and applying the cutting tool to touch the friction surface. When the witness mark passes three-quarters around the surface or more the setup position is right. Use the lathe tools just as the manufacturer specifies while measuring the drum thickness at every stage of work. The brake drum must get replaced when its diameter becomes more than the authorized limit during the refinishing process. Follow guideline speed settings to make a non-directional surface and use 120 grit aluminum oxide sandpaper when you have the finishing tool or sand fabric surface with 150 grit aluminum oxide sandpaper and a low-tech block. Use broken alcohol or brake cleaner to wipe friction areas after applying the final touch and eliminate the brake lathe. For extreme cases apply J 42450-A to remove corrosion from the wheel bearing flange and stop brake system pulsation.

Before starting work raise and stabilize the vehicle under the proper position. Record the wheel position on the axle flange before you take off the tire wheel unit. Keep track of how the drum fits to its axle flange position. Brake performance problems may develop if you push against the floor mat or support plate when taking off the Brake Drum. When the Brake Drum resists removal properly follow these instructions: unclip the retainers, free the parking brake, then use a rubber mallet to tap lightly around the outside of the drum. Avoid striking the inner part close to the spindle. To install the brake hub you must clean both the hub and Brake Drum surface using the tools in the hub cleaning kit (J 42450-A) and the rotor/drum flange resurfacing kit (J 41013). Position the Brake Drum on its marks before returning the tire wheel set to its position and lowering the vehicle.

Lift the car from the ground using equipment to start wheel Brake Drum replacement work. Transfer the wheel position to the axle mount before taking off both tire and wheel parts. Afterward position the drum in relation to the axle flange. Apply light force to the backing plate or splash shield to ward off damage which may cause brake system instability. Start by taking off the Brake Drum and when facing resistance first take off any retainers before making sure to release the parking brake. Lightly tap the drum rim or inner surface next to the Spindle with a rubber mallet in small taps to install the new Brake Drum. You need to use the hub cleaning kit j 42450-a when necessary. Reposition the Brake Drum marks during removal and place the drum back into position before putting on the tire and wheel assembly then lowering the vehicle.

Proceed with brake drum refinement only when the main complaints do not include brake noise sounds or sealant damage issues. You need to refinish brake drums when deep corrosion exceeds the braking surface and causes pulsation while braking. Check the drum brake diameter using a micrometer then replace it with a new part if the largest measurement goes above the maximum modification size. Drum refinishing on brake lathe demands J 41013 Resurfacing Kit to remove rust from the brake drum flange before you follow brake lathe manufacturer instructions to achieve the ideal non-directional braking surface for proper brake operations. Sand the brake surface with non-directional 120 grit aluminum oxide sandpaper after machining and clean it with GM P/N 12377981 or brake parts cleaner substitute. Proper wheel nut tightening with equal amounts of torque protects the braking system from pulsation and keeps rotors intact.

First lift the vehicle and set supports under it for Brake Drum replacement. First locate wheel position on the axle flange and take out the entire wheel tire setup. Line up the Brake Drum position with the axle flange correctly to prevent breaking the splash shield or backing plate by prying force. This can result in brake instability when riding. To simplify Brake Drum removal try eliminating the retainer clips first while checking the parking brake status and tap gently on the drum periphery using a rubber mallet. Avoid applying excessive force that could warp the drum. Install the Brake Drum with the hub cleaning kit (J42450-A). Align the drum placement with the marks from removal. Place the tire and wheel assembly onto the vehicle and drop it back to the ground.

Apply the brakes approximately three times to seat the brake shoes against the drum.

Resurface the drum to a dimension no more than 0.76 mm (0.030 inch) less than the discard diameter.

Ensure to achieve the best possible braking surface finish to prevent stopping difficulties.

Create a non-directional braking surface using 120 grit aluminum oxide sandpaper.

The relationship of the wheel to the axle flange.

Create a non-directional braking surface using 120 grit aluminum oxide sandpaper and clean the braking surfaces with denatured alcohol or a suitable brake cleaner.