help about brakes. (07 Aveo)

**drin21** · October 21st, 2010 10:05 AM

i own a 2007 Chevy Aveo. may grinding sound ang brakes tuwing nasa inclined roads and surfaces. sounds like, "grrrg". you can even feel it on your feet. it happens when the car is put on a full stop. is this normal? if not, ano kaya ang cause nito at anong pwedeng gawin para mawala yung tunog ng brakes?

**miked** · October 22nd, 2010 09:16 AM

Types of Brake Noise
1. Squeak noise when brakes are cold
- usually occuris during 1st few stops
- this is a normal condition and no service action required

2. Squeak noise with brakes at normal operating temps
- semi-metallic pads are noisy compared to OE or ceramics

3. Loud continuous squeak/squeal noise
- occurs with or without braking
- normal brake function when brake pad wear indicators contact the rotor.
indicates brake pads are worn out and need to be replaced
- foreign materials could be trapped in between pad and rotor

4. Groan noise when slightly releasing the brakes after coming to a stop
- sometimes called "creep groan". this is normal and no service action required

5. Groan noise during stopping
- usually caused by glazing of rotor surface as a result of frequent heavy braking
- replace brake pads, then resurface rotors and finish with sand paper

6. Single clunk noise from front suspension when applying the brakes
- can be duplicated by lightly touching the brake pedal
- if brake pedal is pushed hard, the noise is less likely to occur
- the noise is a result of the brake pads shifting in the direction of rotor rotation when brakes are applied
- install appropriate shims and brake grease to pad's steel sliding surfaces

7. Multiple clunk noise
- ABS self-check. vehicle's ABS systems performs a self check when the brakes are applied after initial start-up. this is normal and no service action is required

8. Rear brake squeal
- due to accumulation of brake dust and dirt in between pad/shoes and rotors/drums. clean and lubrication is required

Brake Judder
- caused by rotor thickness variation (RTV) when the inner and outer surface of the rotor are not flat and parallel, the brake pads will follow the low and high spots on rotor during braking causing the brake piston to "knock-back" causing pulsation in the pedal

RTV causes:
1. Rotor run out - if the rotor is not true (perpendicular) to the hub center
2. Vehicle storage - area not covered by pads will rust affecting the friction characteristics between rusted and un-rusted areas
3. Lug nut overtorque - if lug nuts (studs) are overtightened usually with an impact wrench

Hope this helps. i'm sure there are other tsikoteers here with the same problems as yours.
Guys, just add some info. i'm sure my "brake bible" is not that complete.

**drin21** · October 22nd, 2010 10:52 PM

Originally Posted by miked

Types of Brake Noise
1. Squeak noise when brakes are cold
- usually occuris during 1st few stops
- this is a normal condition and no service action required

2. Squeak noise with brakes at normal operating temps
- semi-metallic pads are noisy compared to OE or ceramics

3. Loud continuous squeak/squeal noise
- occurs with or without braking
- normal brake function when brake pad wear indicators contact the rotor.
indicates brake pads are worn out and need to be replaced
- foreign materials could be trapped in between pad and rotor

4. Groan noise when slightly releasing the brakes after coming to a stop
- sometimes called "creep groan". this is normal and no service action required

5. Groan noise during stopping
- usually caused by glazing of rotor surface as a result of frequent heavy braking
- replace brake pads, then resurface rotors and finish with sand paper

6. Single clunk noise from front suspension when applying the brakes
- can be duplicated by lightly touching the brake pedal
- if brake pedal is pushed hard, the noise is less likely to occur
- the noise is a result of the brake pads shifting in the direction of rotor rotation when brakes are applied
- install appropriate shims and brake grease to pad's steel sliding surfaces

7. Multiple clunk noise
- ABS self-check. vehicle's ABS systems performs a self check when the brakes are applied after initial start-up. this is normal and no service action is required

8. Rear brake squeal
- due to accumulation of brake dust and dirt in between pad/shoes and rotors/drums. clean and lubrication is required

Brake Judder
- caused by rotor thickness variation (RTV) when the inner and outer surface of the rotor are not flat and parallel, the brake pads will follow the low and high spots on rotor during braking causing the brake piston to "knock-back" causing pulsation in the pedal

RTV causes:
1. Rotor run out - if the rotor is not true (perpendicular) to the hub center
2. Vehicle storage - area not covered by pads will rust affecting the friction characteristics between rusted and un-rusted areas
3. Lug nut overtorque - if lug nuts (studs) are overtightened usually with an impact wrench

Hope this helps. i'm sure there are other tsikoteers here with the same problems as yours.
Guys, just add some info. i'm sure my "brake bible" is not that complete.

thanks sir!

i got it checked earlier at Rapide. found out that the brake pads are already thin. they will be replaced next week because they have to order Chevy brake pads first.

they also said that the brake discs need refacing or rephasing. i don't know the spelling but it sounded like that. the brake discs are apparently not that flat anymore. the innermost part of the discs are not as flat as the rest of the surface of the discs. they said the discs need to be flattened and smoothed to prevent further damage.

what do you guys think? do my brake discs need refacing or rephasing?

**padone** · October 22nd, 2010 11:06 PM

Originally Posted by drin21

thanks sir!

i got it checked earlier at Rapide. found out that the brake pads are already thin. they will be replaced next week because they have to order Chevy brake pads first.

they also said that the brake discs need refacing or rephasing. i don't know the spelling but it sounded like that. the brake discs are apparently not that flat anymore. the innermost part of the discs are not as flat as the rest of the surface of the discs. they said the discs need to be flattened and smoothed to prevent further damage.

what do you guys think? do my brake discs need refacing or rephasing?

the rotor disc needs refacing if you feel na may nginig or vibration sa brake pedal or sa steering wheel during braking at a certain speed

**drin21** · October 22nd, 2010 11:24 PM

Originally Posted by padone

the rotor disc needs refacing if you feel na may nginig or vibration sa brake pedal or sa steering wheel during braking at a certain speed

combination ng vibration at "grrg" sound that are both coming from the front brakes. di naman sya ramdam sa brake pedal at steering wheel. it happens every time i am in an inclined surface and go to and from a full stop. pag sa patag or leveled roads wala namang sound and vibration.