* Brake Rotors/Drums: Worn-out brake rotors (on disc brakes, usually the front) or drums (on drum brakes, usually the rear) are a common cause. The grinding is the metal-on-metal contact as the pads or shoes wear down past the friction material. This is more noticeable at lower speeds when the braking force is less intense.
* Brake Pads/Shoes: Similar to the above, severely worn brake pads (front) or shoes (rear) will cause grinding. The metal backing plates of the pads/shoes are contacting the rotor/drum.
* Calipers (Front): A seized or sticking caliper piston can cause uneven brake pad wear, leading to grinding. One pad might be constantly contacting the rotor even when not braking.
* Wheel Bearings: While less likely to be the primary cause of a grinding noise *only* during braking, severely worn wheel bearings *can* contribute to a grinding sound, especially when load is placed on the wheel during deceleration. This sound might increase or decrease depending on how much braking pressure is being applied. Usually a wheel bearing will make noise even when not braking, however.
* Parking Brake: A partially engaged parking brake can also cause a grinding noise, but usually this is present even when coasting.
What you should do:
1. Safety First: Do NOT continue driving your Astro van with this grinding noise. Severely worn brakes are dangerous and can lead to brake failure.
2. Visual Inspection: Carefully inspect your wheels and brakes. Look for obvious signs of wear on the brake pads/shoes. If you're comfortable doing so, remove a wheel and inspect the rotor/drum for scoring, grooves, or excessive wear. Note the brake pad thickness. Look for any signs of rust, damage, or debris.
3. Professional Inspection: Take your Astro van to a trusted mechanic or auto repair shop as soon as possible for a thorough brake inspection. They have the tools and expertise to diagnose the problem accurately and safely. They'll be able to assess the condition of all your brake components and recommend necessary repairs or replacements.
Ignoring this noise could lead to a dangerous situation. Brake failure can cause accidents. Get it checked immediately.
