It's not my rotors...

ServO · 08-29-2009, 07:16 PM

Ok...so I was having a problem with a pulsation coming through my brake pedal when stopping...the consensus was that it was most likely a warped brake rotor that was causing the problem since the shimmy was only happening when I applied the brakes, and it seemed more prevelant on the drivers side. We replaced the front rotors and pads today, and as I was driving home I discovered that the pulsation was still there....no change at all...just thumpity thump to a complete stop. Ok, so I know it's not the brakes, and everywhere I search here in the forums, and Google, I get the same thing back..."warped rotor". Does anyone here have any suggestions as to wtf I should start looking at next? I need some wise guidance.

bkathsalero · 08-29-2009, 07:43 PM

tie rod ends?

Vic28 · 08-29-2009, 07:53 PM

Do not over torque your wheels.

undersc0re · 08-29-2009, 08:13 PM

Check the mating surface of rotor to hub and then rotor to wheel, also if anything is out of spec it will make ball joints tie rod end and the rack show any wear at all very easily.

Redog · 08-29-2009, 08:41 PM

Do you have rear drums? Sounds like that to me

jayson_waltz · 08-29-2009, 08:52 PM

sometimes if they tighten the rotors down too tight right away it will warp them. and new rotors need brake in time, so if u just used them heavy like in traffic right away they r probably warped again.

ServO · 08-29-2009, 09:04 PM

Quote:

Originally Posted by Redog

Do you have rear drums? Sounds like that to me

Hmm...didn't think too hard about the rears...I'm fairly certain my rears are disc brakes the same as the front though...I was assuming that the rear disc brakes don't do anything towards stopping the car in traffic and were used when you engage the E-Brake...The front rotors were suprisingly easy to swap out, so the rears shouldn't be a problem to do...I'm starting to get the feeling more that it has something to do with the suspension even though she's not pulling in any direction during takeoffs and stops, and she will hold straight and true if you were to take your hands off the wheel...I dunno...I won't have any more time or money to throw at her 'til next weekend though, so hopefully I'll have an idea what to do by then...

Afugy · 08-29-2009, 09:11 PM

Its hard to believe on our rotors we could warp them by over tighting the lugs, on other cars this could be possible but not the Alero.

Pull the rear rotors off to inspect them. I had this problem before, the rotors had big pits in them and it felt like the problem was in the front, so I never did a proper inspection of the rear brakes. Keep in mind that the rear brakes, if you have rotors on the rear, is a drum/rotor combo, so pulling up on the parking brake will not help.

There are other things that could cause your problem but first do the inspection of the rear brakes.

bigdaddyD · 08-29-2009, 10:11 PM

Could it be bad hubs?

ServO · 08-30-2009, 12:21 AM

At this point it could be Michael Jackson for all I know...but I'm thinking 1. Inspect rear rotors and pads 2. Inspect/replace upper/lower tie rods 3. Investigate front hubs.
Perhaps a complete front end inspection by a professoinal tech is in order, just to nail some things down...

Daytona · 08-30-2009, 09:05 AM

How is the feel and sound when you release the brakes and start to slowly accelerate again? If there's any hesitation or pull it could be your brake assembly not releasing after braking. Happened to me (front left) and over time could be affecting both how it brakes and how it releases.

AlbinoMonkeyRat · 08-30-2009, 10:33 AM

Quote:

Originally Posted by Afugy

Its hard to believe on our rotors we could warp them by over tighting the lugs, on other cars this could be possible but not the Alero.

Pull the rear rotors off to inspect them. I had this problem before, the rotors had big pits in them and it felt like the problem was in the front, so I never did a proper inspection of the rear brakes. Keep in mind that the rear brakes, if you have rotors on the rear, is a drum/rotor combo, so pulling up on the parking brake will not help.

There are other things that could cause your problem but first do the inspection of the rear brakes.

over tightening is the easiest way to warp rotors...esecially if the lugs are at different torques from each other. The heat from the brake pad friction on the rotor would cause the rotor to expand (and contract when it cools) and the varying torques would cause the expansion to happen at different rates, thus causing the rotors to warp.

I have no idea how brake drums work, and I don't intend on ever learning how either. LOL

ServO · 08-30-2009, 11:55 AM

Quote:

Originally Posted by Daytona

How is the feel and sound when you release the brakes and start to slowly accelerate again? If there's any hesitation or pull it could be your brake assembly not releasing after braking. Happened to me (front left) and over time could be affecting both how it brakes and how it releases.

When I release the brake and/or step on the gas, she sounds like a car is supposed to. Even on the freeway (65-75 mph) I feel more stable in my Alero than I do in my GF dad's brand new Range Rover...meaning it's rock solid...the steering is responsive, no pulling to either direction...
It's like there's some ninjas in there or something....

clutch1 · 08-30-2009, 01:41 PM

Ok, go do this... but only if you have drums...

Stop like normal... feel for the pulsing. Next, go and use the e-brake to stop. Pull it VERY gently, otherwise they'll lock up and you won't feel the pulse. If you get some pulse.. then the rear drums and warped.

If you have rear disc, find someone with a dial indicator:

Take the wheel off, then put a couple lugs on to hold the rotor in place. Set up the dial indicator against the rotors surface and spin it... should only read a few thousanths. If you get more than 3 thousanths or so.. rotors are warped and you need to get new ones. You can check the front like this, too.

You can buy those indicators at harbor freight for like $30, too, I think. Don't use it for engine work prolly, but I'd trust it for brake runout. Do this to check for warpage before you go blindly changing things.

Redog · 08-30-2009, 02:11 PM

Yeah what I said only applies to rear drums.

My Delta did exactly what your car is doing and it was the rear drums

ServO · 08-30-2009, 04:49 PM

Oooh Clutch that's a good idea...although, I don't think that it would be a bad idea to swap out rotors if I already have it tore apart...it's not like the rotors and pads are too terribly expensive. I'm thinking they're the original parts...92k miles and 6 years of Minnesota weather can be hard on stuff like that.

paul ron · 10-12-2009, 10:05 PM

I just changed my front rotors because I had pulsations in the steering wheel. After installing new front rotors the pulsations were gone but there was still a slight pulse in the peddle n a rubbing sound that kept pace with the rotation of the tires.

I took appart the rears thinking it was the sliders... the rotors were shot to hell. I changed em and all is good again.

BTW the rear parking brake has an adjustment, one side of the cylinder has a slotted wheel that turns the pads in n out.

.

Afugy · 10-13-2009, 10:40 PM

Servo I want to know how your problem worked out.