Owner's Problem Description
The owner reports a burning smell coming from the driver's rear side after driving even a short distance. They checked for visible issues but found nothing. They noted that the smell started recently and is concerned it could be related to weather conditions or something caught underneath. The tire isn't hot, braking seems fine, but there has been a decrease of about 7-8 MPG recently.
Professional Technical Analysis
For the 2008 Honda Jazz, with approximately 80,000 miles, the reported burning smell from the driver's rear side raises several concerns. The vehicle’s brake system could be a primary suspect, particularly with the noted symptoms of potential brake sticking, which can lead to overheating and burning odors. Monitoring the brake caliper and pads is crucial, as excessive friction can cause heat buildup. The absence of warning lights suggests that the issue may not be electronics-related, but thermal failure in the braking system should be considered. Additionally, decreased fuel economy of 7-8 MPG indicates possible drag caused by the brakes. Intermittent sticking can lead to accelerated wear on brake components, potentially increasing repair costs. A comprehensive inspection of the brake assembly, including caliper operation and pad condition, is essential. Brake pad thickness should be measured; acceptable thickness is typically above 3mm. Furthermore, environmental factors such as recent weather changes may impact brake performance, but the mechanical condition should be prioritized. A proper road test should be conducted, monitoring brake engagement and any unusual noises, while using a temperature gun to assess caliper temperatures under normal operation. This will help identify any components that may be overheating and confirm the source of the burning smell.
Possible Causes
Most common causes (ordered by frequency):
- Brake Caliper Sticking: The brake caliper may be seizing, causing the brake pads to remain engaged partially, leading to excessive heat generation and a burning smell. This can occur due to corrosion, lack of lubrication, or a failed caliper piston. Normal caliper operation should allow for free movement of the caliper on the guide pins, and any binding can lead to uneven wear on pads and rotors. A visual inspection should include checking for fluid leaks and ensuring the caliper moves freely. If the caliper is found to be faulty, replacement with OEM part P/N 45022-SAA-A03 is recommended, typically costing between $100-$200 including labor. - Burning smell when driving, metallic noise when brakes are engaged, visual inspection shows no leaks but caliper movement is restricted.
- Brake Pad Wear: Excessive wear on the brake pads can cause increased friction and heat generation, leading to a burning smell. The pads should be checked for thickness; below 3mm indicates the necessity for replacement. Pads that are worn unevenly can also lead to noise and may affect braking efficiency. If replacement is needed, use OEM pads such as P/N 45022-SAA-A01, costing around $75-$150. - Inspection reveals thin pads under 3mm, potential noise during braking, reduced braking performance observed.
- Brake Fluid Contamination: Contaminated brake fluid can lead to improper caliper function, causing the brakes to engage unevenly. This results in overheating and potential burning smells. Brake fluid should be clear and free of moisture; any discoloration or cloudiness indicates the presence of contaminants. If contamination is found, a fluid flush and replacement with OEM fluid is necessary, typically around $50-$100. - Brake fluid shows discoloration, potential for moisture accumulation, observed in fluid reservoir.
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 - Visual Inspection: Begin with a thorough visual inspection of the brake system components, including calipers, pads, and rotors. Check for any physical damage, leaks, and ensure that the caliper slides freely on its guide pins. Use a flashlight to inspect for any signs of wear or overheating. If any issues are found, document them for further analysis.
- STEP 2 - Brake Pad Thickness Measurement: Use a caliper or depth gauge to measure the thickness of the brake pads. Pads should be above 3mm for safe operation. Document the measurements and compare them against OEM specifications. If pads are worn below this threshold, plan for replacement with OEM parts.
- STEP 3 - Brake Fluid Check: Inspect the brake fluid reservoir for discoloration or cloudiness. If the fluid appears contaminated, perform a brake fluid flush and replace with OEM fluid. Ensure to bleed the brakes thoroughly to remove any air bubbles. Document the condition of the fluid and the procedure performed.
- STEP 4 - Road Test: Conduct a controlled road test to monitor the braking performance. Pay attention to any unusual noises or smells during braking. Monitor brake engagement and ensure the vehicle stops smoothly without dragging. Use a temperature gauge to measure caliper temperatures after braking to identify any overheating issues.
