Car Brake Drum: Things To Know Before Buying One
What Is Brake Drum?
A drum brake is a brake which utilizes the friction which has been caused by a set of shoes or pads that would press outward against a rotating cylinder-shaped part which is known as a brake drum.
Drum brake generally means a brake in which shoes press on the internal surface of the drum. Now when the shoes would press on the outside of the drum, then it is generally known as a clasp brake. When the drum would be pinched between two shoes, which is the same as a conventional disc brake, then it was known as a pinch drum brake. An associated type known as a band brake utilizes a flexible belt or "band" wrapping around the outside of a drum.
Types Of Brake Drum
Depending on how the brake shoes are pressed on to the drums, we have three types of drum brakes. Have a look at them below:
- Leading/trailing shoe type drum brake - "Leading (or primary) shoe" is a term which refers to the shoe which would move in the direction of rotation when it is being pressed against the drum. The other shoe is known as the “trailing (secondary) shoe.
- Twin leading shoe type drum brake - There are two-wheel cylinders and two leading shoes in this type of drum brake. Each wheel cylinder would press on one shoe, so that both the shoes would act as major ones when the automobile would move forward, thus providing top quality braking force.
- Duo servo type drum brake - The duo servo type features a structure where two brake shoes, which are known as primary shoe as well as secondary shoe, are both linked via an adjuster.
Materials Used For Brake Drum
There is a particular type of Cast iron with which the brake drums are made up of. They have high heat conductivity and at the same time are wear resistant. Backplates are generally made of steel. It is the backplates which hold as well as support the entire brake drum unit, so that’s why it should be very strong. That is the reason why they prefer steel.
In the earlier days, chrysotile asbestos was used as brake lining material. But there were a lot of brake mechanics which got issues related to their health due to this material. That’s why slowly and gradually companies began to use synthetic aramids. The material of the brake lining should withstand high temperatures without wearing too much. Aramids are powerful synthetic fibres.
Important Features Of Brake Drum
Here are some essential features of brake drum:
- Drum brakes should provide more braking force than an equal diameter disc brake.
- Drum brakes should last longer because drum brakes have increased friction contact area than a disc.
- Drum brakes should be cheaper to manufacture than disc brakes.
- Make sure that the rear drum brakes should generate lower heat.
- The drum brakes should have a built-in self-energizing effect that would require less input force (such as hydraulic pressure)
- Wheel cylinders should be simpler to recondition than with disc brake calipers.
- Brake shoes should be remanufactured for use in future.
- Drums should have slightly lower frequency of maintenance due to better corrosion resistance.
How Do Brake Drum Work?
When the car driver would step on the brake pedal, then the brake booster would amplify the power and it would be converted into hydraulic pressure (oil-pressure) by the master cylinder. The pressure would reach the brakes on the wheels via tubing filled with brake oil (brake fluid). The delivered pressure would then push the pistons on the brakes of the four wheels. The brake linings would then be pressed by the pistons, which are friction materials. The inside surfaces of the brake drums would be pressed which would rotate with the wheels.
Frequent Problems With Brake Drum
Have a look at some frequent problems with the brake drums:
- If you are feeling that there is some issue in the braking whenever you will press the brake pedal, then there might be some issues with the drum brake system.
- If there are some noises coming from the rear brake drum, there is a need to carefully check the drum braking system.
- If you are braking and then suddenly you start experiencing a shuddering feeling, or you are not able to brake as quickly as you should, then you surely want to decide that what is causing this issue and this can be done by removing the brake drum.
- There can be a lot of imperfections which can cause these issues with the brake drum. First of all you must search for signs of visible cracks, hairline cracks, deep scores and grooves, discoloration, or grease stains.
- There can be some other signs which show that there are some flaws in the brake drum like the excess rust, corrosion or oil on the brake drum, shoes or surrounding brake parts (master cylinder, hoses, lines, springs). Make sure to get your brake drums serviced if you are facing any such issues.
Symptoms Of Bad Brake Drum
If there are some flaws in your brake drum, then it would start producing the following symptoms to alert the driver that some issue has been occurred.
- Unusual brake pedal feel - First symptom of faulty drum brakes is that there might be unusual brake pedal feel. If there is a lot of wear and tear in the brake drums, then it might cause vibrations that may be felt in the pedal.
- Scraping noises when brakes are pressed - One another symptom which is generally related with the defective brake drums are abnormal sounds. Now if the brake drums would become worn out, then they might give off a scraping or scratching sound when the brakes are depressed.
- Loose parking brake - If there are some quirks in the drum brakes, then it would give rise to the loose parking brake. Now if the drum brakes would wear, then the shoes would not be able to squeeze against the inside of the drum and due to that the parking brake might not be able to work properly.
Tools Needed For Brake Drum
It is said that a workman is only as good as his tools, and it is definitely true when it comes to the car bodywork. It is vital to have the right tools to repair your Brake Drum or else a straightforward job would turn into constant headaches. So that’s why we have listed out some invaluable tools below which you will need while repairing your Brake Drum.
Top Brand For Brake Drum
Most of the people have a nature to avoid risk and seek safety. That is the reason why they would go with a familiar auto parts brand than a new one. It would prove to be safe and they know what to expect. Have a look at our top brands for Brake Drum which would offer safety and at the same time decrease the risk of disappointment.
Related Parts Of Brake Drum
Total Costs & Repair Times, Effort For Brake Drum
I bet that you’re thinking as to how much does a Brake Drum replacement cost. Just keep in mind that it is not as easy as putting a fast and hard number on it. This is because the replacement/repair cost would be different for every Brake Drum and it would also vary from The average brake drum price for its replacement would be between $337 and $502 and depending on how in-depth the repair needs to be. If you are thinking about the exact cost, then you might take help of an expert mechanic.
How To Change Brake Drum?
Here are the steps to change the brake drum:
1. The first and the foremost step would be to take the wheel of
- The car should then be parked in a clear, flat area.
- The lug nuts should be loosened up before raising the automobile.
- The automobile should be lifted up with a jack.
- The lug nuts should be unscrewed and then remove the wheel.
2. The next step would be disassembling the drum
- The adjuster screw should be turned to loosen the shoes.
- Unscrew the brake drum as per the requirements.
- If you are facing some troubles, then you can always use a screwdriver and a rubber mallet.
- Then remove the brake drum with a brake drum puller.
3. After that it is essential to work on the drum and wheel
- The drum should then be cleaned properly.
- Carefully restore the shoes.
- Inspect the wheel cylinder for leakages in the hydraulic.
- Check the brake lines for some defects.
- After that you should consider repacking the wheel bearings.
- The brake drum should be replaced when finished.
- Then you should restore the wheel to finish.