Grinding noise from the front

[sarotara]

2004 Chevrolet Impala (9C1 ex-police, naturally aspirated, 85000 miles)

I'm getting a strange grinding noise (sounds like scraping a rock across the ground) from the front end of the car. This noise starts happening a few minutes after driving the car. The longer you drive it, the more frequently it starts occurring. Also, it only happens when the car is in the 13-18 mph speed range and only when the car is slowing down (braking or coasting), never when accelerating (gas pedal or downhill) through that speed range.

The car had this problem when I bought it at 82000 miles and I thought that it was an issue with the front brakes. I replaced the rotors and the brake pads. Also, there seems to be no play in the front wheel hubs. I'm out of ideas at the moment. Any help would be appreciated. Thank you.

[maxwedge]

See if you can pinpoint this ft wheels off the ground car in gear, use proper safety techniques of course.

[j cAT]

Originally Posted by sarotara

2004 Chevrolet Impala (9C1 ex-police, naturally aspirated, 85000 miles)

I'm getting a strange grinding noise (sounds like scraping a rock across the ground) from the front end of the car. This noise starts happening a few minutes after driving the car. The longer you drive it, the more frequently it starts occurring. Also, it only happens when the car is in the 13-18 mph speed range and only when the car is slowing down (braking or coasting), never when accelerating (gas pedal or downhill) through that speed range.

The car had this problem when I bought it at 82000 miles and I thought that it was an issue with the front brakes. I replaced the rotors and the brake pads. Also, there seems to be no play in the front wheel hubs. I'm out of ideas at the moment. Any help would be appreciated. Thank you.

check all the plastic in the wheel wells for security...these plastic fasteners wear out then the plastic panels wander into the tires...

[sarotara]

Originally Posted by maxwedge

See if you can pinpoint this ft wheels off the ground car in gear, use proper safety techniques of course.

Outside of placing the car jacks under car's frame front frame, setting the parking brake, and placing chocks behind the back wheels, is there anything else I should be doing? I won't have a chance to do this until the weekend... I will let you know how it goes.

[sarotara]

Originally Posted by j cAT

check all the plastic in the wheel wells for security...these plastic fasteners wear out then the plastic panels wander into the tires...

I'll check out the wheel wells this evening. However, I don't think that this would explain why the noise occurs only at certain speeds and only when the car is slowing down...

[j cAT]

Originally Posted by sarotara

I'll check out the wheel wells this evening. However, I don't think that this would explain why the noise occurs only at certain speeds and only when the car is slowing down...

at a certain speed the plastic will flex out of position by air forces then when braking the front end dips slightly....this can be an interference problem....

[sarotara]

Originally Posted by j cAT

at a certain speed the plastic will flex out of position by air forces then when braking the front end dips slightly....this can be an interference problem....

I checked the wheel wells and there is nothing that I can see that could be scraping against the tires... I considered the possibility that air might be flexing some plastic in the area out of position but it doesn't explain why the noise doesn't happen in the first few minutes of driving the car and then starts happening more often the longer the car is driven. If some plastic was being bent out of position, I would think that you would also get this type of noise at higher speeds and when braking more aggressively.


The only plastic near the wheel wells that has any potential of touching the ground or the tires would be the splash guards, and I highly doubt that they are the problem. They're made out of some type of plastic that's not all that flexible, and I highly doubt that air forces would bend them forward towards the front tires, considering that they're placed behind the front wheel wells.

[j cAT]

[quote=sarotara]I checked the wheel wells and there is nothing that I can see that could be scraping against the tires... I considered the possibility that air might be flexing some plastic in the area out of position but it doesn't explain why the noise doesn't happen in the first few minutes of driving the car and then starts happening more often the longer the car is driven. If some plastic was being bent out of position, I would think that you would also get this type of noise at higher speeds and when braking more aggressively.


as the engine gets hot the plastic gets softer....grab on to plastic don't just LOOK at it,,,, see if it can move into the tire area...


the plastic pins that secure the panels are defective and wear out..


look and move the panels inside the engine compartment for inteference with the engine belt pulleys etc...

[sarotara]

Double checked the wheel well areas for interference with tires... There is nothing in there that I can see that could potentially scrap up against the tires.

[cat man]

heres a long shot ... does your car have speed sensors on the front hubs ? if so maybe one of them might have got jard durring a pursuit ? and causing your noise ??

[cat man]

also you said you replaced the front rotors ? did you also replace the wheel bearings and seal ?

[sarotara]

Originally Posted by cat man

also you said you replaced the front rotors ? did you also replace the wheel bearings and seal ?

Nope, replaced just the rotors and the pads.

[sarotara]

Originally Posted by cat man

heres a long shot ... does your car have speed sensors on the front hubs ? if so maybe one of them might have got jard durring a pursuit ? and causing your noise ??

I don't believe that the front hubs have speed sensors... I could be wrong however. Here are the pictures from the front pad and rotor replacement.

http://ornus.org/images/impala_2004_front_rotors_pads/

[cat man]

you may want to inspect and replace the bearings and seals ? and make sure you get a proper preload on the bearings .

[cat man]

ok i see you have a two piece hub and rotor ? and if im correct those bearings are sealed . i had a beretta with the same annoying symptoms and it was the bearings .,,,,,,,,,,,, good luck and let me know?