Jim Grant's Tech Tips
97 Toyota Corolla, Phantom Brake Grind
Q:
I have a '97 Toyota Corolla. In the past three months I have
noticed when I brake I hear a grinding noise. I have taken it to my mechanic
and he changed the back brakes and the front brakes are in good condition.
No sooner left the garage it did it again. So a couple days later he took
the car in and put on a new drum and to this day it's still doing it.
I stopped at another garage and one of the mechanics heard it and said
that it possibly could be a bushing. My mechanic just can't seem to diagnose
what is causing this to happen. Hopefully you will have some answers to
my problem.
A:
Does the grinding noise
occur when the brakes are applied? Or is it a random grinding noise, maybe
when turning? Because you say that the rear brakes and one rear brake
drum was replaced then, is the noise from the rear of the vehicle? Was
one brake drum replaced because the noise was from that side of the vehicle?
Can you make the noise occur if you lightly apply the emergency brake?
Or does it cause the grinding noise to stop? I know it's a lot of questions
but it does create a path to aid in solving the problem. About every shop
has run into problems like this and when the answer is found it has always
seemed to be a simple fix. Be sure to check the routing (inside the brake
drum) and adjustment of the emergency brake. There is a return spring
on the cable inside the brake drum. Sometimes there will be enough bend/bow
in the cable that the spring contacts the inside of the brake drum. All
it takes is a light touch to make a big noise. The touch of the cable
can be so light that it will hardly leave a rub mark on the brake drum.
If the brake drum is new and clean it will be even harder to see. That's
just one thought. I tend to doubt that the brakes (shoes or drum) are
the cause for the noise. It's going to be some little piece that is rubbing
just right that is causing this noise to irritate you, and form stomach
acid for you technician.
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