* Worn or damaged rear brake components: This is a high probability. Hard braking can exacerbate existing problems. Possible culprits include:
* Rear brake pads or shoes: If severely worn, they can cause a thumping or grinding sound.
* Warped rotors or drums: Hard braking, especially when the brakes are already hot, can warp the rotors (disc brakes) or drums (drum brakes), leading to a thumping sensation.
* Loose or damaged caliper: A sticking or seized caliper piston can cause uneven braking force, leading to a thump.
* Broken or worn caliper mounting hardware: This can lead to instability and noise.
* Suspension components: Hard braking can put significant stress on the suspension. Possible issues include:
* Worn or broken shock absorbers: These dampen the bounce of the suspension. If worn, they can allow excessive movement, leading to thumping.
* Worn or damaged bushings: These rubber components help absorb vibrations. Worn bushings can allow excessive movement and noise.
* Loose control arm: A loose control arm can cause a variety of noises, including thumping, especially under stress like hard braking.
* Damaged leaf springs (if applicable): If your Cherokee has leaf springs in the rear, a broken or severely weakened leaf can cause thumping.
* Other possibilities (less likely):
* Something loose in the rear: While less likely to be directly related to braking, something loose (spare tire, tool, etc.) might be shifting and impacting something during hard braking.
Troubleshooting steps:
1. Visual inspection: Carefully examine the rear brakes and suspension components for any obvious damage, wear, or looseness. Look for cracks in the brake components, excessive wear on the pads/shoes, and signs of fluid leaks.
2. Check brake fluid level: Low brake fluid suggests a leak which needs immediate attention.
3. Test the brakes: Carefully test the brakes at low speed to see if you can reproduce the thump.
4. Check for wheel play (Excessive movement): Grab each wheel at the top and bottom and try to rock it. Excessive play could indicate worn suspension components.
Recommendation:
Since hard braking is involved and this could indicate a serious safety issue, it's best to have a qualified mechanic inspect your Jeep Cherokee as soon as possible. Ignoring the problem could lead to brake failure or suspension damage. Don't attempt extensive repairs yourself unless you are experienced in automotive repair.
