Why does the car still roll backward when parked on a slope with the handbrake pulled?

[LeMatteo]

It may be caused by a loose cable or issues with the rear wheel braking system, and it is recommended to visit a 4S shop for inspection as soon as possible. Below are the relevant explanations: 1. Handbrake: The professional term for the handbrake is auxiliary brake. Unlike the principle of the main brake, it uses a steel cable connected to the rear brake shoes to brake the car. Long-term use of the handbrake can cause plastic deformation of the steel cable. Since this deformation is irreversible, prolonged use will reduce its effectiveness, and the handbrake travel will increase. 2. Braking: After pulling the handbrake, it utilizes a hydraulic auxiliary cylinder to push the main hydraulic cylinder beneath the car, which drives the air valve (designed this way to avoid hearing air noises in the cabin). Once the air valve is activated, it brakes the drive shaft. The handbrake only brakes the drive shaft.

[Ramos]

I also encountered such scary situations in the first two years of driving, where the car would roll even with the handbrake engaged on a slope. The main issue lies with several components of the handbrake system. The most common problem is a loose handbrake cable. Over time, the cable can stretch, making it seem like the handbrake is pulled high, but the brake pads aren’t pressing tightly enough. Another possibility is worn-out rear brake shoes, especially for cars frequently parked on slopes using the handbrake—brake pads wear out much faster than when parked on flat ground. Additionally, for manual transmission cars, remember to engage reverse or first gear to utilize engine resistance for auxiliary braking. Once, on a steep slope, my car rolled nearly half a meter with just the handbrake, but it held steady once I engaged a gear. Finally, check the handbrake lever’s travel; if it feels very loose even when pulled to the top, it’s a clear sign that adjustment is needed. Parking on a slope with a rolling car is particularly dangerous—if you notice anything wrong, head to a repair shop immediately to adjust the handbrake system.

[Miguel]

I've encountered this issue several times, especially when driving older manual transmission cars. Even with the handbrake engaged, the car would slowly roll backward, which was quite nerve-wracking. Later, a mechanic explained there are three main reasons: First, the handbrake cable tension becomes insufficient over time as the cable stretches, preventing the brake pads from gripping tightly. Second, excessive wear on the rear brake pads reduces their thickness, naturally decreasing stopping power. Third, parking on slopes that exceed the handbrake system's braking capacity. A useful tip is not to release the foot brake immediately after parking - engage the handbrake first, then gradually release the foot brake to test if the car is secure. For manual transmission cars, leaving it in a lower gear provides effective additional braking, while automatic transmission cars can be shifted to Park after applying the handbrake. If the car still rolls with the handbrake fully engaged, don't force it - promptly visit a professional repair shop for inspection and adjustment.

[AliyahFitz]

Rolling back after parking on a slope is commonly caused by aging handbrake systems. Firstly, the handbrake cable may stretch and loosen over time, potentially providing only 80% braking force even when pulled to its highest position. Secondly, rear brake shoe wear accelerates, especially for vehicles frequently parked on slopes, reducing pad lifespan by about one-third. For manual transmission vehicles, it's recommended to engage gear braking; for automatic transmissions, use the parking pawl in P mode. During a recent garage visit, mechanics found that loose adjustment nuts on handbrake cables can also cause this issue. Regular handbrake efficiency checks are crucial—testing its effectiveness on gentle slopes is advisable.

[VonSamuel]

Rolling back on a half-slope usually indicates insufficient braking force from the handbrake system. I once experienced this and found three main causes: loose handbrake cables leading to inadequate brake pad pressure, severely worn rear brake shoes, and slopes exceeding 30 degrees making the handbrake ineffective. Manual transmission cars can enhance braking by leaving them in gear, but the fundamental solution is timely maintenance. Now I've developed a habit of ensuring the vehicle is completely stationary before exiting. If I notice the handbrake travel has lengthened or the car moves slightly when fully engaged, I immediately get the handbrake adjusted. During every maintenance session, I have the mechanic check the rear brake pad thickness and replace them early if they're too thin.