1. Identify the Severity and Symptoms:
* How severe is the drag? Is it a slight resistance noticeable only at low speeds, or a significant drag that significantly impacts fuel economy and generates excessive heat?
* Is it both front brakes or just one? This helps isolate the problem to a single caliper or a system-wide issue.
* Is there a noise? Grinding, squealing, or a low humming sound can indicate specific problems.
* Does it happen all the time, or only after braking? This can point to sticking calipers versus other issues.
* Is there a smell of burning brakes? This indicates significant friction and potential damage.
2. Potential Causes:
* Sticking caliper pistons: This is a very common cause. The pistons may not be retracting fully after braking, keeping the pads in contact with the rotors. This can be due to corrosion, seized slides, or a faulty caliper.
* Seized caliper slides: The caliper slides allow the caliper to move freely as the pads wear. If they're seized, the caliper can't move, causing dragging.
* Worn or damaged brake pads: While worn pads usually don't *cause* dragging, severely worn pads might allow the caliper to get closer to the rotor and stick.
* Low brake fluid: While unusual to *cause* dragging, very low brake fluid can suggest a leak somewhere in the system that might be related.
* Parking brake cable: A partially engaged parking brake cable can drag the rear brakes, but it's less likely to affect the fronts. However, if the cable is somehow binding, it could theoretically affect front brakes indirectly.
* Brake lines: A kinked or restricted brake line could restrict the return of fluid, causing dragging. This is less common.
* Master cylinder: A faulty master cylinder could contribute, but it's less likely to affect only the front brakes.
3. Troubleshooting Steps:
* Visually inspect the front brakes: Look for anything obvious like seized caliper pistons, severely worn pads, or damaged components.
* Check for brake fluid leaks: Look for leaks around the calipers, brake lines, and master cylinder.
* Try to manually move the caliper pistons: If you can gently push them back in with your fingers, that indicates a sticking issue. (Be careful, use gloves, and if it's stuck, don't force it.)
* Check the parking brake: Make absolutely sure it's disengaged.
* Drive the vehicle: Pay close attention to whether both sides are dragging equally or if one is worse than the other. This helps pinpoint the location.
4. If you're not mechanically inclined:
Take your E350 to a qualified mechanic. Diagnosing and repairing brake problems requires specific tools and knowledge. Ignoring dragging brakes is dangerous and can lead to significant damage, overheating, and brake failure. It is NOT a DIY job for someone without experience working on brakes.
Safety First: Dragging brakes are a serious safety concern. Drive carefully and avoid heavy braking until the problem is fixed.
