Nissan Murano 2012 Bumping Noise In Back When Stopping

Alright, let's dive into that frustrating bumping noise you're hearing from the back of your 2012 Nissan Murano when you stop. It's a common complaint, and while it can be caused by a few different things, we'll systematically break down the most likely culprits, giving you the knowledge to diagnose and potentially fix it yourself. We'll be looking at the rear suspension, braking system, and even some less obvious possibilities. Finding the cause of these sounds is important, not just for your peace of mind, but also to prevent any potential safety risks and further damage to your vehicle.

Background: Murano's Rear Suspension and Braking Systems

Before we get into specific troubleshooting, let’s get a quick refresher on the relevant systems in your 2012 Murano. Understanding the fundamentals helps in diagnosing any problem.

Rear Suspension

The 2012 Murano typically uses an independent multi-link rear suspension. This design is meant to provide a comfortable ride and good handling. Here are the key components to keep in mind:

Control Arms: These are the links that connect the wheel hub to the vehicle's chassis. Multiple arms (usually upper, lower, and sometimes lateral links) control wheel movement in various directions.
Coil Springs: These support the vehicle's weight and absorb bumps in the road. They work in conjunction with the shock absorbers.
Shock Absorbers (Dampers): These control the movement of the springs, preventing excessive bouncing. They dampen oscillations and keep the tires in contact with the road.
Stabilizer Bar (Sway Bar): This connects the left and right sides of the suspension, reducing body roll during cornering. It's attached with end links to the suspension components.
Bushings: These are rubber or polyurethane pieces that act as cushions between the suspension components and the chassis. They absorb vibrations and allow for movement without excessive noise.

Rear Braking System

Your Murano likely has a disc brake system in the rear. Here’s the lowdown:

Brake Rotor: This is the spinning disc that the brake pads clamp onto to slow the vehicle down.
Brake Caliper: This houses the brake pads and pistons. The piston(s) push the pads against the rotor when you apply the brakes.
Brake Pads: These are friction materials that contact the rotor to create friction and slow the vehicle.
Brake Lines: These carry brake fluid from the master cylinder to the calipers.
Parking Brake Mechanism: This is a separate system (often integrated into the rear calipers) that locks the rear wheels when the vehicle is parked. Some Muranos use an electric parking brake, which will have a different mechanism with actuators.

Technical Breakdown: Possible Causes of the Bumping Noise

Okay, now let's get into the potential causes of that bump. We'll categorize them for clarity.

Suspension-Related Issues

Worn Bushings: This is a very common cause. Over time, the rubber bushings in the control arms, stabilizer bar end links, and shock absorbers can degrade, crack, and wear out. This allows excessive play in the suspension components, leading to a bumping or thumping noise, especially during braking when weight shifts forward. Inspect the bushings carefully for cracks, tears, or excessive movement. A pry bar can be helpful to check for play.
Faulty Shock Absorbers: If a shock absorber is leaking fluid or is no longer effectively damping the spring oscillations, it can cause the suspension to bottom out or bounce excessively, resulting in a bumping noise. To test, visually check for leaks. Also, push down firmly on the rear of the vehicle and release. The car should rebound smoothly and settle without excessive bouncing. If it bounces more than once or twice, the shocks are likely worn.
Broken or Sagging Coil Springs: While less common, a broken or sagging coil spring can also cause a bumping noise. A broken spring will be visually obvious. A sagging spring will cause the vehicle to sit lower on that side. Measure the ride height on both sides of the rear to check for significant differences.
Loose Suspension Components: Make sure all nuts and bolts on the suspension components are properly torqued. A loose bolt can cause movement and noise. Use a torque wrench and consult the vehicle's service manual for the correct torque specifications.
Stabilizer Bar End Links: These are small links that connect the stabilizer bar to the suspension. If they are worn or loose, they can rattle and cause a bumping noise, especially when going over bumps or during braking. Inspect the end links for play or damage.

Braking System Issues

Worn Brake Pads: Severely worn brake pads can sometimes cause a bumping noise, especially if the backing plate is contacting the rotor. Check the brake pad thickness. Most pads have wear indicators that will squeal when the pads are nearing the end of their life.
Loose Brake Caliper: A loose brake caliper can rattle and cause a bumping noise, particularly during braking. Make sure the caliper mounting bolts are properly torqued. Again, refer to the service manual for the correct torque specifications.
Warped Brake Rotor: A warped brake rotor can cause a pulsation or vibration during braking, but it can also sometimes manifest as a bumping noise. Check the rotor surface for uneven wear or damage. You can use a dial indicator to measure rotor runout.
Parking Brake Issues: If the parking brake mechanism is sticking or binding, it can cause a bumping noise, especially after releasing the parking brake. Inspect the parking brake cables and levers for proper operation. If your Murano has an electric parking brake, a malfunction in the actuator can also cause similar symptoms. A diagnostic scan with an OBD-II scanner that can read ABS codes might be necessary to diagnose electric parking brake issues.

Other Potential Causes

Exhaust System: A loose exhaust hanger or a damaged exhaust pipe can cause the exhaust system to bump against the chassis, especially during braking when the vehicle's weight shifts. Inspect the exhaust system for any loose hangers or signs of damage.
Loose Items in the Cargo Area: Believe it or not, a loose jack, spare tire, or other items in the cargo area can sometimes sound like a suspension or brake issue. Make sure everything in the cargo area is properly secured.
Rear Differential Mounts: (Less Common) If your Murano is all-wheel drive, worn differential mounts can allow the differential to move excessively, causing a bumping noise. Inspect the differential mounts for cracks or tears.

Common Issues and Maintenance Concerns

Here are some recurring issues you might encounter while diagnosing this problem:

Frozen or Rusted Bolts: Suspension components are often exposed to the elements, and bolts can become frozen or rusted, making them difficult to remove. Use penetrating oil and allow it to soak for a while before attempting to loosen the bolts. Heat can also be used, but exercise caution to avoid damaging other components.
Incorrect Torque Specifications: Using the wrong torque specifications when reassembling suspension components can lead to premature wear or failure. Always consult the vehicle's service manual for the correct torque specifications.
Misdiagnosis: It's easy to misdiagnose suspension noises. Take your time and systematically check each component. Don't just replace parts without properly diagnosing the problem.

Do's and Don'ts / Best Practices

Do's:

Do use proper safety precautions. Always use jack stands when working under a vehicle.
Do use penetrating oil on rusted bolts.
Do consult the vehicle's service manual for torque specifications and procedures.
Do replace components in pairs (e.g., both shock absorbers or both brake pads on the same axle).
Do perform a thorough inspection of all suspension and brake components.
Do test drive the vehicle after making repairs to ensure the problem is resolved.

Don'ts:

Don't work under a vehicle supported only by a jack.
Don't over-tighten bolts, as this can damage the threads or weaken the component.
Don't reuse self-locking nuts.
Don't ignore unusual noises or vibrations. They are often a sign of a problem.

Conclusion and Recommendations

Tracking down a bumping noise in the rear of your 2012 Nissan Murano can be a bit of a detective game, but by systematically checking the suspension, brakes, and other potential sources, you can often pinpoint the cause. Start with the most common culprits: worn bushings and faulty shock absorbers. Carefully inspect each component, looking for signs of wear, damage, or looseness.

If you're comfortable with basic automotive repair, you can likely tackle many of these repairs yourself. However, if you're not confident in your abilities or if the problem is complex (like an electric parking brake issue), it's best to consult a qualified mechanic. A professional diagnosis can save you time, money, and potential headaches in the long run. Don't ignore the noise for too long, as it could indicate a safety issue or lead to more expensive repairs down the road. Good luck, and happy wrenching!