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Snowskate

2000 Legacy GT Pulsating Brakes

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A buddy of mine is having problems with his brakes pulsating and from what I understand is that he drove with the E-Brake on all the way home, and I'm thinking that he heated up the rear rotors and warped them.

 

Took everything apart today but couldn't find any signs of being warped (probably naked to the eye besides any discolorations which I didn't see). Unfortunately I didn't have my micrometer with me to measure the rotors but I'm hoping I can get away with turning them as my buddy is low on money at the time.

 

After turning the rotors will they be prone to warping again depending on how much is left to each rotor? I've heard NAPA will turn them for $15 a rotor, is it worth it?

 

Thanks.

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Welcome to the USMB.

 

I personally have not had good luck with turning rotors, so I usually just replace the rotors with new rotors.  After turning the rotors, they will have less material and could be prone to issues again (depending on how much material was removed).  If you money is tight and this is just to get by, as long as they're within the service limit, you could do it and replace the rotors later.

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Same thought as you..........that the rotors are warped. If you think because the parking brake was left on while driving, then it is only the rear rotors that are bad. Not too costly if you buy on line from Advance Auto Parts with coupon deductions, or elsewhere on line.

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Maybe I'll check up to see what the prices are for rear rotors and go from there. For some reason I'm not 100% sure if it is the rear rotors but there's not much else it could possibly be.

 

Thanks for the thoughts and greetings :P  

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Maybe I'll check up to see what the prices are for rear rotors and go from there. For some reason I'm not 100% sure if it is the rear rotors but there's not much else it could possibly be.

 

Thanks for the thoughts and greetings :P  

I remember what you wrote about the parking brake being left on as a source of warped rotors in the rear, however, most of the braking of any car is with the front brakes, so I suspect the front rotors are the ones causing the problems. Whenever I have had warped rotors, it always felt like the pulsating sensation was coming from the front of the car, and the sensation being transmitted through the brake pedal, and even felt throught the steering wheel. Replacing the fronts usually fixed the problem.

 

After thinking about this, it may be better to replace the front rotors first.

Edited by Rooster2

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Yes, I usually redo all the wheel lug nuts after getting tires since the shop guys go crazy with the impact gun.

 

Do you feel the pulsating more in the brake pedal or the steering wheel?  If it's more in the brake pedal, the chances are more likely that the rear brakes are the problem.  If you feel it more in the steering wheel the fronts are more likely the cause.

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Did you test drive your buddys car prior to taking apart the brakes??? The rear parking brake is a shoes and drum setup inside the rear rotor so if it was left on only the drum in theory should be warped.. which I personally have not come across and Im not certain but I dont think the parking shoe compound is the same as the brake pad compound and potentially would just wear down quickly but not create excessive heat... And if he was able to drive around with the parking brake on then it was way out of adjustment and not really doing much (could be the drum in the rotors being at or past its max diameter spec)... I did this with my 96 impreza one time and when I took it all apart thinking I destroyed my shoes there was actually no true damage/harm done just much smaller parking brake shoes. Adjusted them up and my car would not anywhere with my E-Brake on.

So if you are driving at like 25+ MPH and hit the brakes does the whole car shake? Or just the steering wheel or as your coming to a stop do the brakes feel to be dragging/catching. If the whole car shakes at 25 MPH its most likely the front rotors being warped. I just did this on my car because it was driving me nuts. I just machined the rotors and have been good to go.... But if it feels like your brakes are dragging as you come to a stop it is most likely the rear rotors being warped. I have misdiagnosed this as front rotors in the past and after repairing and test driving the issue was still there. Throw rear rotors on and it was gone... Also if the rears are solid rotors I would just go ahead and replace them, Never had much luck with machining solid rotors.

And machining the rotors all depends on what the mic specs compared to manufacturer specs are. And if your close to the minimum machining spec just replace them... Most people dont consider the fact of how thin these can get and in one instant of heavy braking (like on the highway) can warp them severely.

Oh and one more thing to keep in mind is the balance on the tires. I still had a bit of a shake on heavy braking after doing my rotors and went ahead and checked my tire balance (which was out quite a bit) and now I have nice smooth braking at any speed

 

Hope this helps,

Greg 

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Did you test drive your buddys car prior to taking apart the brakes??? The rear parking brake is a shoes and drum setup inside the rear rotor so if it was left on only the drum in theory should be warped.. which I personally have not come across and Im not certain but I dont think the parking shoe compound is the same as the brake pad compound and potentially would just wear down quickly but not create excessive heat... And if he was able to drive around with the parking brake on then it was way out of adjustment and not really doing much (could be the drum in the rotors being at or past its max diameter spec)... I did this with my 96 impreza one time and when I took it all apart thinking I destroyed my shoes there was actually no true damage/harm done just much smaller parking brake shoes. Adjusted them up and my car would not anywhere with my E-Brake on.

So if you are driving at like 25+ MPH and hit the brakes does the whole car shake? Or just the steering wheel or as your coming to a stop do the brakes feel to be dragging/catching. If the whole car shakes at 25 MPH its most likely the front rotors being warped. I just did this on my car because it was driving me nuts. I just machined the rotors and have been good to go.... But if it feels like your brakes are dragging as you come to a stop it is most likely the rear rotors being warped. I have misdiagnosed this as front rotors in the past and after repairing and test driving the issue was still there. Throw rear rotors on and it was gone... Also if the rears are solid rotors I would just go ahead and replace them, Never had much luck with machining solid rotors.

And machining the rotors all depends on what the mic specs compared to manufacturer specs are. And if your close to the minimum machining spec just replace them... Most people dont consider the fact of how thin these can get and in one instant of heavy braking (like on the highway) can warp them severely.

Oh and one more thing to keep in mind is the balance on the tires. I still had a bit of a shake on heavy braking after doing my rotors and went ahead and checked my tire balance (which was out quite a bit) and now I have nice smooth braking at any speed

 

Hope this helps,

Greg 

 

 

Good call Pgh_Scoob, the rear parking brake arrangement is indeed a small drum w/shoes. I had forgotten this, and posted earlier that it was simply pads and rotor. My post was wrong. Very likely the front rotors are warped and causing the problem.

 

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