Front wheel drive (FWD) cars are designed differently than rear wheel drive (RWD) or all wheel drive (AWD) vehicles when it comes to how power is distributed to the wheels. But one thing all cars have in common is a braking system with components on both the front and rear axles. So do front wheel drive cars have rear brakes?
The short answer is yes. All FWD cars have brakes on both the front and rear wheels. But the braking system on each axle works a bit differently to safely slow and stop the vehicle.
Braking System Basics
Before diving into the details on FWD brakes, let’s review some braking system basics:
- Disc brakes use brake pads that squeeze a rotating disc or rotor between calipers to create friction and slow the wheel. Discs provide greater stopping power and dissipate heat faster than drums.
- Drum brakes use curved brake shoes pressed against the inner surface of a rotating drum to stop the wheel. Drums are a simpler, less expensive design.
- Hydraulic circuits use brake fluid under pressure to activate components in the braking system. Applying the brake pedal pushes pistons to engage the pads or shoes.
- Proportioning valves regulate hydraulic pressure to balance front and rear braking force. More pressure goes to front brakes where more stopping power is needed.
Now let’s look at how these basics come together in a front wheel drive braking system.
Brake Configuration in FWD Cars
The typical braking system found on a front wheel drive car consists of:
- Disc brakes on the front wheels
- Drum brakes on the rear wheels
- A proportioning valve to balance braking power between axles
This configuration provides maximum stopping power from the front brakes while the rear brakes provide supplementary braking force.
Front Disc Brakes
Disc brakes are used on the front wheels of FWD cars because:
- The engine’s drive power is delivered to the front axle
- Weight shifts forward during braking, increasing friction demand on front tires
- Discs provide stronger braking and better heat dissipation
Front disc brakes use ventilated rotors that allow air to pass through and cool the discs. Ventilation is important for front brakes since they do the majority of the work when stopping the vehicle.
Rear Drum Brakes
While the front discs do the heavy lifting, rear drum brakes play an important supplemental role in braking FWD vehicles. Here are some of the advantages rear drums provide:
- Compact, lightweight design ideal for rear axle
- Fully enclosed design protects internal components from dirt, water, etc.
- Low friction design generates less heat than discs
- Simple, low-cost maintenance and repairs
Rear drums don’t require as much stopping power, so they can get by with a less sophisticated design. Enclosing the braking components also keeps the system cleaner compared to exposed front disc components.
Less friction means rear drum brakes operate at lower temperatures than front discs. This allows the rear brake components to last longer before needing service.
How Rear Brakes Support Front Brakes
You might think that if front brakes provide 70% or more of the stopping power, the rear brakes aren’t that important. But don’t underestimate the key support role that rear drum brakes play:
Stability – Rear brakes prevent fishtailing and keep the rear wheels from locking up. This complements the front brakes to maintain control.
Rolling Resistance – When parked facing downhill, the rear brakes prevent the car from rolling by locking the rear wheels.
Emergency Braking – Under hard braking, rear drums prevent the back of the car from skidding sideways.
So while front brakes provide the brute force, rear brakes are crucial for maintaining stability and control when coming to a stop.
Mechanical Differences Between Front and Rear Brakes
Now that we’ve covered why FWD cars have brakes on both axles, let’s look at the mechanical differences between front disc and rear drum systems:
Front Disc Brakes
|Rotors||Metal discs mounted to the wheel hub that spin with the front tires|
|Calipers||Houses brake pads and hydraulic pistons that force pads against rotors|
|Brake Pads||Friction material pressed against rotor surface when braking|
|Brake Fluid||Hydraulic fluid that transfers pressure from brake pedal to calipers|
When the brake pedal is pressed, hydraulic pressure pushes the caliper pistons to clamp the pads against the spinning rotor. This friction slows the wheel and stops the vehicle.
Front discs provide strong braking power with rapid heat dissipation. But the high friction surface also wears down brake pads fairly quickly.
Rear Drum Brakes
|Brake Drums||Rotating cylinders mounted to rear wheel hubs|
|Brake Shoes||Curved blocks lined with friction material|
|Wheel Cylinders||Contains hydraulic pistons that push shoes against drum|
|Return Springs||Retracts shoes away from drum after braking|
When the brake pedal is applied, the wheel cylinder pistons activate and push the curved brake shoes out against the spinning drum. This friction slows the rear wheels.
The lower friction design means rear brake components don’t require service as often as front disc components. But rear drums can be trickier to inspect and service.
Brake Maintenance Tips
Maintaining your brakes is critical to staying safe on the road. Here are some key maintenance tips:
- Inspect pads and rotors – Front discs should be checked at every oil change. Replace pads that are under 3mm.
- Check brake fluid – Fluid should be changed every 2 years as moisture builds up over time.
- Inspect drums and shoes – Rear drums should be checked yearly. Shoes are OK unless worn to 1.5mm.
- Listen for noises – Squealing, grinding or thumping sounds indicate a brake service is needed.
- Watch for vibration – A pulsating brake pedal or steering wheel is a sign of warped front rotors.
- Change hydraulic fluid – Rubber brake lines should be replaced every 10 years to avoid bulges and cracks.
Catching minor problems early on can help avoid pricey brake repairs down the road. Following the manufacturer’s maintenance schedule is highly recommended.
Frequently Asked Questions
Here are answers to some common questions about front wheel drive braking systems:
Do front wheel drive cars have rear disc brakes?
Most FWD cars have rear drum brakes to keep costs down. But some models offer rear disc brakes for enhanced performance and towing capacity.
What percentage of stopping power is from front vs rear brakes?
Front brakes provide 70-80% of the stopping force in most FWD vehicles. The rear brakes contribute the remaining 20-30%.
Do rear drum brakes have brake pads?
No, drum brakes use curved brake shoes rather than pads. The friction material is bonded to the curved shoes.
Can rear brakes work if the front brakes fail?
Yes, but stopping distance will increase dramatically with only the rear drum brakes operational. The rear brakes alone cannot safely stop the vehicle.
Do both front wheels have brakes on a FWD car?
Yes, FWD cars have disc brakes on both front wheels. The braking system is usually divided diagonally into separate hydraulic circuits.
While front wheel drive cars deliver engine power to just the front axle, all FWD vehicles rely on brakes at both the front and rear. Front disc brakes provide most of the stopping force, while rear drums provide stability and prevent rolling when parked.
Proper brake maintenance and inspection of key components like pads, rotors, shoes and drums is crucial to staying safe on the road. Understanding how both braking systems work together on a FWD car provides insight into keeping your brakes in top shape.