What Do Brake Pad Shims Do in a Car?

No matter how quiet the engine of your car might be, you are still going to make little noises as you roll down the street. Brake shims can lessen vibration and lessen the sound waves your car gives off. They can also soften the blow of the vibrations. In some cases, shims may come with your car and in other cases, you will have to buy them separately.

Brake pad shims are small pieces of metal or rubber designed to reduce the noise in your car.

Where are they Used in a Car?

Brake shims are attached to the brake pad of your car. They can be found between the pad and caliper.

When you drive a car the wheels and the brakes cause a vibration.  Whenever anything vibrates, it causes air molecules to move. Those molecules bump into one another and that is how sound waves are formed.

The level of noise is determined by the way vibrations are transferred to other components in the vehicle. Shims reduce vibration and therefore reduce noise as well.

Some brake pads are made with shims and others have to be stuck to the pad with tape or glue. There are also peel-off shims that have an adhesive backing. These have to be stuck onto the back of the brake pad very carefully. The quality of the shim will depend upon the material that it is made out of. Very high-quality shims will attach to the brake pads with pins.

One of the most important things about a brake shim is the adhesive that is used to attach it to the pad. If the shim does not stay on the pad it can be damaging to the brake system and your car certainly won’t be any quieter.

A brake shim should last as long as your brake job. You should never have to go back to the mechanic because your brake shims are acting up.

How Important are Brake Pad Shims?

Your car will operate just fine without brake pad shims, but it may be kind of noisy. Shims are not required in any way, but there are a couple of circumstances in which they will not only cancel noise but give you a better ride overall.

Shims have several hidden benefits depending on the type of vehicle on which they are used and the type of material of which they are composed.

4 Signs Your Brake Pad Needs Brake Shims

If you want a quieter ride, shims can definitely help. In some cases, a car without shims may benefit from having some installed. In other cases, your brake pads may have shims that have not been installed correctly.

1) Your Car is Making Too Much Noise

If your car is making too much noise as you drive down the road, you may want to get brake shims to reduce the noise.

2) Your Brakes are Getting too Hot

If your brakes heat up when you drive down the road, titanium brake pads may actually help to prevent them from getting too hot. We have all seen movies involving car chases or watched the police chase someone on the news. When brakes work too hard, they get hot. When titanium is used in a brake shim, it can actually protect your breaks from getting too hot.

Unlike their not so fancy counterparts, titanium shims are not attached to the brake pad with adhesive. They are placed between the brake pad and the caliper and slipped onto the caliper pins. 

3) Your Shims Were Installed Incorrectly

When a shim slips off, it can cut into the brake rotor. When shims are attached to the pad with cheap glue or too much or too little glue, they can melt off and damage other parts of the brake system.

Shims with pins must be securely fastened to the brake pad or they can come apart as well. Miss aligned shims or those that have fallen off will need to be replaced.

Sometimes shims will simply become corroded, will fall apart eventually, and fall off. This can cause rust to get into the brake system and create a spongy brake pedal. Some shims attach to the brake pad with tabs. These tabs are very secure and eliminate the problem of shims falling off.

4) Bonus – You Want your Motorcycle Ride to be Smoother

When you think of a noisy vehicle, you can’t help but think of a motorcycle. Motorcycles use rubber shims and they not only reduce noise but make for a smoother ride.

They can actually help to align the tires of a bike. It is always a good idea to get shims on your brake pads when you have a motorcycle because they help increase the friction of the breaks. A motorcycle rider will be able to come to a smoother stop if they have to slam on the breaks quickly.

What Kind of Shim is the Best?

You should know that shims will not make your car completely silent, it will just make it quieter. Some mechanics will tell you that the better the material used in a shim the better it will work. Others will tell you that the best shims will depend on your car.

How to Install Brake Pad Shims

If you are keen on installing your own brake pad shims, there are a couple of tools you’ll need for sure.

Tools Needed

  • Wrench
  • Jack
  • brake-piston retractor
  • A hook

Step 1

Park the vehicle on a level surface. If you have an automatic car, put it in parking mode. If you have a clutch, put it in first. Loosen the lug nuts around the tire. Take the jack stand and jack the car up. Remove the lug nuts and take the wheel off.

Step 2

Remove the caliper-guide-rod bolts. Roll the caliper back and forth and spread the brake pad out. Take the caliper off the disc and suspend it from the hook.

Step 3

Take the clips that hold the brake pads to the caliper off, and slide the brake pads away from the caliper.

Step 4

Retract the caliper piston using your brake-piston retractor. Then place the swivel portion of the retractor on the piston face. After that, put the metal plate of the retractor on the inner surface of the outer caliper frame, tighten the spindle with your wrench, and the piston will go back into the cylinder bore.

Step 5

Put the shim on the back of the brake pad. If you are using an adhesive shim, take the wax paper off of the shim’s surface and press it onto the pad. The piston should contact the middle of the shim. Some shims will attach with pins or clips.

FAQs

Do all brake pads come with shims?

No, in some cases, you will have to buy them yourself.

Can I remove shims from brake pads?

If you have titanium shims or something else that attaches to the brake pad with hooks or pins, you should be able to remove them. If they are adhesive, they may be hard to get off, but not impossible.

Is it necessary to grease brake shims?

It is not necessary but it is a good idea. If part of your brake system is rusty, it will only cause noise, and noise is what shims prevent.

Can you reuse brake pad shims?

You can reuse shims that are made of metal. However, most brake shims are made to attach to the pad with glue and they may not be worth rescuing.

Having shims installed by a mechanic.

The cost of having brake shims installed will depend upon the type of brake pad and shim that you select. You will normally get it done whenever you get new brake pads. The average brake pad replacement costs approximately $150 per axle.

If you spend a little money and get the right kind of shims for your car, you will be able to go wherever you want in peace and quiet.

Author: DJ

Dave Junior is a hands-on automotive technician with experience in performing service, diagnostics, and repairs on domestic and imported vehicles. He enjoys writing and sharing his knowledge far and wide.

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