What Causes the Noise When Braking in Reverse on a Sagitar?
5 Answers
The reason for the noise when braking in reverse is due to the moving caliper hitting the caliper bracket during the process of reversing. Below are the relevant explanations: 1. Radar System: When the car moves from the warning zone into the danger zone, the radar system automatically activates the braking device to control the car's reverse movement. The principle is based on an ordinary reverse radar, with the addition of a servo device that has a braking function. When the car enters the danger zone from the warning zone, the controller sends a control signal to the braking servo, which immediately activates to automatically stop the car from reversing further, ensuring safe reversing. 2. Braking: When driving forward and braking, there is no 'play gap' at the lower connection part of the brake bracket, so no noise occurs. However, when braking in reverse, the brake caliper lifts up and hits the upper bracket, causing the noise.
A couple of days ago, my neighbor's Sagitar had the same issue—it made a squeaking noise when braking while reversing. Common causes could be too many metal particles in the brake pads, which is especially noticeable on rainy days. Or the edges of the brake discs might have rusted, causing noise when the calipers rub against the rust layer while reversing. Last time, my own car had a small stone stuck in it—no noise when moving forward, but it screamed when reversing. I suggest trying a few normal brake applications in a row to wear off the rust layer. If the noise persists, go check the brake pad thickness and caliper slide rails. I’ve heard they need replacement if the thickness is below 3mm.
As a seasoned driver who has owned three Sagitars, let me share some insights. The squeaking noise when reversing is mostly due to issues with the rear brake system. This phenomenon was particularly common in the first-generation Sagitar, and it was later discovered to be caused by the material composition of the brake pads. The high metal content made them too hard, resulting in a screeching sound when rubbing against the brake discs—like nails on a chalkboard. After switching to low-metallic brake pads on my current Sagitar, the noise disappeared. Additionally, check if the brake dust shield is deformed and rubbing against the disc. Last winter, my car had this issue and squeaked for quite a while.
My Sagitar 1.4T has been making a squeaking sound when reversing after recent car washes. The mechanic said this is a normal physical phenomenon: a water film left on the brake disc surface forms an oxide layer, and when reversing, the brake pads rub against the thin rust layer in the opposite direction. It's like the sound of a new bowl bottom rubbing against a table. Pay attention—if it's a brief, sharp sound, it should disappear after a few normal brakes while driving. However, if it's a metallic clanging sound, it might be due to lack of lubrication in the guide pins causing them to seize, which needs immediate attention.
Three common causes of reverse braking noise: If the brake pads are newly replaced, a 200-kilometer break-in period is required, especially for ceramic pads. For vehicles that have been driven 20,000-30,000 kilometers, it's likely due to wavy wear patterns on the brake discs. The third common cause in northern winters is misaligned friction caused by frozen anti-vibration shims on the brake pads. My 2018 Sagitar experienced the third issue, which was resolved by using a heat gun to warm the caliper area. It's recommended to first check the disc surface for obvious uneven grooves.
