How to Use Brake Lubricant


Image Gallery: Brakes Your brakes use friction to slow and stop your car, but you might be surprised to learn that your brakes also need proper lubricant to work properly. See more pictures of brakes.
©iStockphoto.com/genekrebs

The brakes on your car cause it to slow and stop by using friction. The brake pads press against the rotor or drum in the wheel, whether it's a drum brake or a disk brake. Using lubrication on a system that requires friction might seem like a bad idea, but the correct lubricants are crucial to proper brake function.

Of course, you never want to put lubricants of any kind on the friction surface of the brakes. That's where the stopping power comes from, and lubricant would cause your brakes to simply stop working. But brakes have lots of moving parts, and they all need to be well-lubricated to make sure everything works smoothly. Brake lubricants also keep your brakes from making squealing or screeching noises due to vibrations, and they reduce wear and tear so your brakes will last longer.

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Lubricating brakes isn't just a matter of slathering some oil or grease. Special lubricants are required because of the conditions under which brakes operate. For one thing, brakes get very hot, with even moderate use. An ordinary lubricant would actually melt in these conditions, and could then run or splatter onto other parts of the brake system, including the rotor or pads. Slippery brake rotors won't work. Also, virtually all modern brake systems are hydraulic. Petroleum-based lubricants would make rubber and plastic seals deteriorate.

If you're getting ready to do a brake job, don't forget to buy the proper lubricants along with your new pads and rotors. For metal-on-metal lubrication, look for dry film lubricants containing either molybdenum disulfide or graphite. To lubricate areas with rubber or plastic components, use silicone-based or synthetic non-petroleum lubricants.

Now, let's get down to the business of explaining where to put the lubricants and how to apply them.

Drum Brake Lubrication Points

Whether you have an older vehicle that uses drum brakes, a newer vehicle that uses them for cost-efficiency, or a smaller vehicle like an ATV, there are few key places that need lubrication. Here are a few helpful hints that will help you lubricate your drum brakes properly.

  • Don't ever put lubricant on the inside of the drum where the shoes/pads contact the drum. This will cause the brakes to stop working, and could be very dangerous.
  • Use lubricant on the backing plate. You'll find small ridges where the shoe rests; these can be sanded lightly with a grinding wheel, and then lubricated.
  • The adjustable star-wheel that separates the shoes can be prone to freezing, so it should be lubricated.
  • The parking brake usually uses the rear drum brakes in your car, so lubricate the parking brake cable and any linkages or moving parts.
  • Make sure you lubricate the separator located about halfway up the shoe.
  • Use lubricant anywhere you find metal-to-metal contact between moving parts, such as where the shoes slide.
  • Don't use dry film lubricant where the lube might contact rubber or plastic seals.
  • Don't overlubricate -- you don't want excess lubricant dripping into places it shouldn't go.

Next, we'll find out where to lubricate disk brakes.

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Disk Brake Lubrication Points

Be careful where you apply brake lubricant -- improper application can have serious consequences.
Be careful where you apply brake lubricant -- improper application can have serious consequences.
©iStockphoto.com/flyrfixr

Due to their shape, disk brakes work a little differently than drum brakes -- and therefore have slightly different lubrication points. Here are a few do's and don'ts to keep in mind as you work on your disk brakes.

  • Because it's so important, here's that reminder again: Don't ever put lubricant on the rotors or the insides of the pads where they contact the rotors. This will kill your brakes and cause you major problems on the road.
  • Lubricate the few small screws on top and bottom of the caliper that hold it in place.
  • The bushing that moves the caliper itself back and forth should be properly lubricated. If not, it can freeze up and fail to disengage the brakes properly. This will affect your gas mileage and cause excess wear on your brakes.
  • Where the caliper rides on the frame along the rotor, you may find some wear marks. Lightly sand those with a grinder and coat with lubricant.
  • Anywhere metal slides along metal -- such as where the pads slide inside the caliper housing -- should be lubricated.
  • Again, always use dry film lubricant, except in places where the lube might contact rubber or plastic seals.

Now that you know where to apply brake lubricant, let's learn how to apply it. We'll discuss that on the next page.

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Applying Brake Lubricant

All of the parts of your brake system are continually exposed to road spray and salt (if you live in a wintery climate). Brake wear generates dust from the rotors and pads wearing away. As a result, the braking mechanisms can get rusty and dirty. The first part of applying brake lubricant is cleaning them up.

Use a die grinder to clear away any rust on parts where you plan to apply lubricant. Grind just until you get to bare metal. Then put a bucket or pan underneath the brake assembly and spray the entire brake mechanism with brake cleaner. This will carry away the brake dust and drip down into the pan, which avoids the dust contaminating the air. This is especially important if, for some reason, you're working on old asbestos brakes. Once the brake cleaner has drained away, collect it and store it for proper recycling or disposal.

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Brake lubricant usually comes in a tube or a small canister. Most mechanics just apply it where needed with a finger, but if you'd like more precision, you can use a wooden tongue depressor. Remember to only apply a thin coating where needed. Overlubrication of the brakes results in lubricant dripping or spraying into places where it's undesirable, and could reduce the effectiveness of the brakes.

For more information on brakes and other auto parts, cruise on over to the next page. 

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Sources:

  • Carley, Larry. "Brake Lubricants." Brake & Front End, July 1, 2006. (Accessed Oct. 22, 2010)http://www.brakeandfrontend.com/Article/38625/brake_lubricants.aspx
  • Grabianowski, Marty. Mechanic. Personal interview, Oct. 26, 2010.
  • Molykote. "From the Pedal to the Pad." (Accessed Oct. 22, 2010).http://www.dowcorning.com/content/publishedlit/80-3306-AUTO.pdf