Owner's Problem Description
The owner reports that the brakes on their 2002 Dodge Grand Caravan are not releasing properly. They have already replaced the calipers, pads, brake lines, and the master cylinder, and have flushed the brake fluid. However, the brakes continue to drag, causing them to heat up and smoke. They are seeking further diagnostic advice on potential causes.
Professional Technical Analysis
The 2002 Dodge Grand Caravan is equipped with a hydraulic brake system that utilizes disc brakes on the front and rear wheels, with an anti-lock braking system (ABS). The vehicle has a history of intermittent brake dragging, particularly after the owner replaced several key components, including the calipers, pads, brake lines, and master cylinder. Despite these efforts, the brakes continue to overheat and smoke during operation, indicating a potential issue with brake fluid flow or pressure retention. The symptoms suggest that the problem may lie in the brake hydraulic system, particularly with the calipers or rubber flex hoses. The dragging brakes release when the bleeder screws are opened, pointing to possible sticking pistons in the calipers or issues with the flex hoses. The ABS hydraulic controller may also be contributing to the issue, as internal leakage could cause pressure retention. A thorough inspection of all components, including the ABS controller, is crucial to diagnose the root cause effectively. Current brake performance is unsafe and requires immediate attention to prevent further damage or potential brake failure while driving.
Possible Causes
Most common causes (ordered by frequency):
- Caliper piston sticking: The newly replaced brake calipers may have pistons that are sticking due to corrosion or debris. This can cause the brake pads to remain in contact with the rotor, leading to overheating and smoke. A brake caliper rebuild kit (e.g., OEM P/N 4762164AA) can be used to replace seals and ensure smooth operation. - Brake pads show signs of uneven wear, caliper pistons are difficult to compress manually.
- Rubber flex hose failure: The rubber flex hoses that connect the brake lines to the calipers may have deteriorated internally, causing a restriction in fluid flow. This can trap pressure in the calipers and prevent proper release. Replacement hoses (e.g., OEM P/N 52119292AA) should be inspected and replaced if necessary. - Visual inspection shows bulging or cracking in the rubber hoses.
- ABS hydraulic controller issue: The anti-lock brake system's hydraulic controller may have internal blockages or malfunctions that prevent proper fluid return to the master cylinder. This could lead to increased brake pressure and dragging. A complete diagnostic check of the ABS system is recommended. - ABS warning light may be illuminated; diagnostic codes may indicate issues with the hydraulic controller.
Diagnostic Steps
Professional Diagnosis Process
Follow these systematic steps to accurately diagnose the issue. Each step builds on the previous one to ensure accurate diagnosis.
- STEP 1 - Initial Inspection: Begin with a visual inspection of all brake components, including calipers, brake lines, and hoses. Look for signs of fluid leaks, corrosion, or physical damage. Ensure all connections are secure and check for any signs of heat damage or discoloration on brake components.
- STEP 2 - Bleeder Screw Test: Open the bleeder screws on the calipers to see if fluid pressure is retained when brakes are applied. If brakes release after opening the bleeder, it indicates a potential issue with caliper pistons or rubber flex hoses.
- STEP 3 - Brake Line Pressure Testing: Use a pressure gauge to measure the brake line pressure at the master cylinder and at each wheel. Normal pressure should be consistent across all lines when brakes are applied. Any inconsistencies may indicate blockage or restriction.
- STEP 4 - ABS System Diagnostic: Connect an OBD-II scanner or GeekOBD APP to check for any ABS fault codes. This can provide insight into potential issues with the ABS hydraulic controller or related components.
