Grinding noise, need opinions, help!

[96GrandAm]

Grinding noise...

Ok, first - I did a search and read a bunch of past
discussions like a good little noobie. But am not totally
convinced I've diagnosed my noise right, so I am looking
for opinions.

'96 Grand Am 110,000 miles, decent care.

Last summer I started detecting an ever so slight grinding
noise that was intermittent and mostly on more spirited
accelerations from a stop. Seemed like maybe turning
while accelerating caused it a bit more often than not.

The sound stayed like that till a month ago. It had
progressed to just about every acceleration from a stop,
and really sounded like a worn brake pad chewing into a
rotor. Since it needed front brakes anyway, I started
thinking that I had a hung caliper on one side and the
other had worn quicker and the pad wore away and the
shoe's metal backing was scraping on the rotor.

Since my own shop (hobby) was full with broke cars and
it was too cold to do it outside, I took two new rotors
and rebuilt calipers to a shop that I trust and asked them
to throw them on for me.

They did a nice job as they always do, and I didn't ask
what the actual state of rotors that came off was.

Within a day the grinding noise was back, but very
infrequent and less intense.

Experimenting a bit showed me that with a very soft launch,
It was very unlikely to make any sound at all. And again
acceleration AND turning made it more likely.

So, I thinking now bearing hub that's the closest match.

My sound is definitely driver side front wheel.

What do you think?

Joe

[96GrandAm]

Wow, did I stump you guys... <grin>

I'm seriously considering it as NOT being
the bearing hub.

Joe

[rixGAphx]

Wow, did I stump you guys... <grin>

I'm seriously considering it as NOT being the bearing hub.Nah, you just sounded like you knew enough to figure it out yourself.

We're too busy telling numbskullz with multiple idiot lights, serious noises, and no braking action to park their cars until a professional can look at their POS. :roll:
* * *
I don't see anything in your post to indicate bearing problems.
The noise of a failed/failing bearing is usually a deeper 'rumbling' than I'm audibly-picturing (???) from your description of the 'scraping' noise.

And since it 'went away' for a couple days after the calipers/pads/rotors were replaced, that indicates to me that at least part of the shop's action 'solved' the noise, if only temporarily.

Personally, I would re-do the brake job and reassemble with lubrication on the slide pins and wear points and 'anti-squeal' on the backs of the pads.
Those are the only things that 'scrape', that is, stationary metal contacting moving metal.
This would give me th chance to personally-inspect the inside of the assembly, mebbe find a bent piece of something that occasionally touches the rotating rotor or axle.

The shop may have inadvertently re-used slide pin(s) that should have been replaced.
If the slide pins aren't perfect, they might prevent the outer floating bracket from retracting properly when pedal pressure is released.

And on a 12-yr old car, there are numerous opportunities for non-hub/brake-assembly parts to deteriorate.
* Plastic inner fender pieces might have dislodged such that they're actually scraping the tire.
* There's very little clearance between the spring bottom seat and the tire sidewall; I once had a piece of gravel in the shoulder tread produce a rhythmic 'scrape-scrape-scrape' as the gravel contacted the spring seat once every tire revolution.
* If the suspension parts (bushings, strut bearing plates, tierod ends, ball joints) are worn, then the relationship of the steering knuckle/hub to the rest of the chassis 'shifts' a little bit, mebbe 1/4" both side-to-side and fore-aft, as the front end is loaded from braking to a stop, hard-cornering left then right, and as power is applied thru the axle and tires to the road.

Perhaps braking 'unloads' the components and allows them to shift to a poistion where contact necessary for scraping ceases.
Flooring the vehicle re-establishes the contact by shifting the components.
But a mild take-off doesn't produce enough 'shifting' for contact to occur, and thus the noise is gone.

I just can't picture WHAT is making contact against which rotating part.

A simple test of the front components is:
* Jack and support one side of the car, with tire 'dangling'; place tranny in 'P', lock the steering wheel.
* Grasp tire at 9:00 and 3:00, and push-pull firmly.
* Repeat with hands at 12:00 and 6:00.
Looseness at 3/9 = faulty tierod ends/steering linkage.
Looseness at 12/6 = faulty ball joint(s).
Looseness at both = faulty bearing.
Or various combinations, depending on how heavily-abused the car might have been.

Time to spend some quality time with your GA's front end.

Hope this helps,
-Rick

[96GrandAm]

Rick,

That was an exceptional post.

I really got a big kick out of the first part:

We're too busy telling numbskullz with...

Yes, I know enough to fix things, just don't know these
cars all that well. Roll the model year clock back a decade or more
and I'm golden.

What I was hoping for was for someone that's worked with these
machines a bit to share their thoughts about likely items to focus
on. And that you did, and quite well...

I thank you very much Sir.

I normally wrench on older Pontiacs, but love my GA and want it
right. I have lurked here for quite a while, and have always been
impressed by this site and it's community.

Joe R

[g4mbl3]

btw rick, my name is nick, not "numbskullz" as i know you were referring to me, and i myself am 17 with no exceptional experience in car repair, so i came to ask a question, not to be ridiculed. thank you

[96GrandAm]

Hi Nick...

From reading the forum rules, the nice folks that spent all the
time, effort and money set forth some guidelines they wanted
to see.

One such guideline is not to hijack or steal a thread. This thread
is actually about my grinding noise.

Another is about differences needing to be placed in a Private Mail,
or email... not in the forum itself.

But since you have a grinding noise too, I can see why you stopped
by.

I went back and read your question. What I saw was well thought-out
practical advice. Personally, from what I read I'd conclude that you
have a brake system failure. I agree with the advice already given.

Don't drive it. I can understand not having cash, we've all been there.
But driving that thing anyway is asking for a tragedy.

If Rick got your attention and was successful in getting you to park
that thing, personally, I'd think another more sincere Thank you is in order.
He may have saved your life and those of other innocent people.

Joe R

[arthurgoboom]

Joe,
Have you checked the condition of the drive axles at any point? A grinding or clicking noise especially during turning can indicate a CV joint problem. When you have the car up on stands, reach in and grab the drive axle and try to move it up and down and front and back. It shouldn't move. Also check the rubber boots carefully for tears or grease leaking out anywhere.

[coupe]

Rick,
Yes, I know enough to fix things, just don't know these
cars all that well. Roll the model year clock back a decade or more
and I'm golden.

Actually both drum and disk brakes havent changed much if any since the begining. Roll the clock back a decade and your still lookin at pretty much the same exact setup.

[96GrandAm]

Have you checked the condition of the drive axles at any point? A grinding or clicking noise especially during turning can indicate a CV joint problem.

Nope, haven't. Don't have much experience with them. Everything else I got is RWD...

well, except for my Fiero.

Actually both drum and disk brakes havent changed much if any since the begining

Yes Sir, that is very true. Since I have new rotors and calipers, it's most likely
something else like a CV joint. And those aren't on my RWD old Pontiacs.

But thanks to Rick and "arthurgoboom" I have tests to learn and narrow
down things more.

Again, Thank you folks... I appreciate your time.

Joe R

[rixGAphx]

btw rick, my name is nick, not "numbskullz" as i know you were referring to me, and i myself am 17 with no exceptional experience in car repair, so i came to ask a question, not to be ridiculed. thank you:eek:



OMG :D :D

Of course I was referring to you.
You're the only numbskull currently active in this forum.

I appreciate that you're a young driver searching for assistance in solving mechanical problem(s) with your car.
And I appreciate that you're a mechanical novice and I'll cut you a lot of slack for that.
I applaud all attempts to gain knowledge whether automotive or otherwise, and I don't condemn or ridicule anyone for lack of knowledge or experience at any stage of life.

The ridicule wasn't directed at you for ignoring the idiot lights, nor even for not acting upon the scraping noise.

It was for the idiocy and/or arrogance that caused you to enter the roadway without working brakes.
I condemn anybody whose specific actions and lack of common sense endangers others.
It is this lack of common sense that qualifies you as a 'numbskull'.
Yeah, I'm abrasive at times, and I'll catch some heat from the site mods for this rudeness; afterall, 'flaming' in the Technical Forums' isn't allowed.
But if my rudeness has truly gained your attention, it will be worth it.
If not, you may be in for a tough life.

Drop the 17-yr old bravado, and apologize to the parents of Philly for endangering their children's lives by driving without brakes.
Twice.

Regardless of your level of mechanical expertise, the state of PA granted you a driver's license because you demonstrated the proficiency necessary to operate a motor vehicle.
This also carries the responsibility of knowing when NOT to drive: If you are impaired by lack of sleep or by medication, or if the weather is too bad, or if your headlights don't work, or many other reasons/conditions.
You are EXPECTED to know that your vehicle MUST HAVE an operational brake system that will stop the vehicle within a reasonable distance.

If it doesn't, then PARK IT.
Right THERE.
Right NOW.

We are all fortunate that you didn't kill any children in the crosswalk on their way to or from school.

It was dangerous and illegal of you to have not parked the car when you knew the brakes weren't working.
Twice.

You acted like a numbskull.
But there is hope. You can change.
Learn from this episode and move on.

Peace,
-Rick

PS: If I were your parent, you'd be grounded so long for this lack of maturity and responsibility that you'd have more than enough money for repairs by the time you saw your license again.

[rixGAphx]

Since I have new rotors and calipers, it's most likely something else...That's twice now that you've stated new rotors and calipers, without stating 'new pads.'

These aren't the former pads, re-installed with the new mechanicals, are they??
'Cuz the inner pad often has that little 'wear bar' that's SUPPOSED to make some noise as the pad thickness diminishes.

[96GrandAm]

Yep, you're right I missed saying either way.

Yes, brand new pads...

and with regards to getting the attention of anyone,
trying to drive without brakes... hopefully you or
someone gets through. To that end, a little rude
isn't the same as flaming someone. If I where a
moderator here, I'd be fine with your thoughts
and presentation.

Joe R