High pitched squeal from FR when driving

[cp1]

I've been working on a friends alero for nearly three weeks now and what is happening is that after about 10 minutes of regular city driving (enough time for everything to heat up) a loud and almost unbearable intermittant squeal that increases in frequency and loudness as you you travel faster can be heard coming from the passengers front wheel, so it definately has to come from the rotation of the wheel. The noise disappears completely when the brakes are pressed firmly but when very lightly depressed it is worse. It does not matter if you turn the car left of right.

at the beginning we took the wheel off and removed the calipers and brake pads i properly scuffed the disc and the pads again and applied new silicone based lubricant to all the mating points and those little copper shims then reasembled everything. the noise seemed to have gone away for about a week.

when it returned i redid everything i did before only this time i measured the thickness of the discs to just reconfirm my suspicion that indeed the discs had been warped pretty badly but they were not thick enough to be turned, so after replacing both front discs and then reinstalling everything it was time to take it for a test drive. Victory! i thought. it had driven fine and there was no noise to speak of, so i gave the car back to the owner and she was pleased.

however she calls me about 8 hours after that and complains that the noise is back, tho a little quieter now, Now im upset. and i have absolutely no idea where this noise could be coming from, I have already lubed up the back of the pads, replaced the discs and rebuilt the calipers twice. I am pretty sure it wouldnt be the bearing because ive been told that on these cars when they go it tends to make a grinding sound not an intermittant squeal.

If anyone could offer any points or suggestions i would be grateful.

[BNaylor]

What condition are the pads in? Thickness? I didn't see whether you had replaced them. The noise sounds like the wear indicator.

[jrozanc]

It might be possible you have got a funky wheel bearing. Alero's like to have wheel bearing problems. Bearings can do funny things under pressure and heat.

[JTrujillo86]

My brakes did this when they needed to be replaced. The wear indicators are made to squeel constantly until the brakes are applied. Also, check the rotors to see if they need to be turned. If they do, its best to do it when you replaced the pads.

Jeremy

[cp1]

problem appears to be solved, i decided just to replace the pads this time just for good measure they were going to need to be done soon anyway and found that the caliper mounting bracket had actually been very slightly bent. So a different used bracket went on as well as the new pads and what do you know not a sound... so far. i doubt it should come back but my guess is that it was a combination of having worn brakes coupled with a bad bracket that was holding the caliper at an angle to the rotor. hence the crazy wear on the right hand side.

Total cost of doing the brakes yourself

2 new rotors $82.90
new pads for both sides $32.48
2 packs Syl-glide $5.00
Brake cleaner $3.27
Used bracket from neighbor $Free

Total: $128.15 CDN Incl. Tax!!!!

You may want to look at this the next time you take your car to a shop and pay $500 this if done in one session may have only taken 2 hours tops and with an ALERO the brakes are very simple to work on.

[vamc]

Originally Posted by JTrujillo86

My brakes did this when they needed to be replaced. The wear indicators are made to squeel constantly until the brakes are applied. Also, check the rotors to see if they need to be turned. If they do, its best to do it when you replaced the pads.

Jeremy

True..but make sure they have not been turned before. you can only do this once b/c they will be to thin. just a thought.

[cp1]

Originally Posted by vamc

True..but make sure they have not been turned before. you can only do this once b/c they will be to thin. just a thought.

the minimum wear allowance that most shops will take a rotor down to is 5 thousandths however it is recommended that you replace them at about 15 thousands or less. you can have a rotor turned as many times as this will allow because turning them on average takes off about 2 thousands of the surface. just enough to remove any glazing.

[vamc]

ok. i thought it was closer to 7. but ok.cool