Crunching noise in back when braking [Archive] - GrandAmGT.com Forum

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zelda4325
07-15-2005, 07:58 AM
My friend jsut bought a 95 toyota 4runner, with 160,000 miles. Most of the time when he brakes hard or hits a bump , there is a crunching noise from the back but the car stops fine. i was thinking it mightbe the drum brakes but since it stops fine so i was thinking it migtbe the shocks. Any clues of what it could be, what should i look for? Thanks for the help in advance

Malaclypse
07-15-2005, 11:07 PM
My car has rear drums and does this. Here's what I've figured out. Just haven't got around to replacing the parts yet.

His rear drums are probably getting really thin. That being said, last time anyone cleaned and adjusted his rear brakes they might have set them too tight. This slight yet constant drag causes heat to build up in the drums. Under a hard braking condition coming up to a stoplight the shoes will put alot of force on the drums. This causes the drums to warp because they're already hot.

Since the drums warp, whenever the rear brakes apply, the shoes undulate inward and outward with the warpage of the drum. This causes a creaking or crackling sound because the rear shoes are scraping against the backing plates

What to do to resolve this? Replace both rear drums and rear pads. clean and adjust brakes. lube the backing plates at the three contact points for the shoes and you're done.