TexasLegacy2.5GT Posted May 2, 2012 Share Posted May 2, 2012 I've had this shudder on my BD since I bought it back last year. To further describe the shudder it feels just like warped rotors would feel. I know about the warped rotors after a set on my Old Isuzu Impulse Turbo went bad. All I did for the Impulse is replace the front rotors and it went away. I recently bought brand new rotors all around for my legacy. After installing the new front rotors and new brake pads I tried it on the street and the moment of truth came: Nothing had changed! Absolutely NOTHING! My mechanic assured me that it must be the rear rotors that are warped...it just feels like it's shaking from up front. Any advice? Link to comment Share on other sites More sharing options...
Baddog Posted May 2, 2012 Share Posted May 2, 2012 If you can feel it in the steering wheel it's up front. Bad wheel bearing? How do your axles look? Could even be shot bushings Link to comment Share on other sites More sharing options...
underground000 Posted May 2, 2012 Share Posted May 2, 2012 did you bed in the brakes? 5eat downshift rev match:) Powder coated wheels: completed:) Link to comment Share on other sites More sharing options...
TexasLegacy2.5GT Posted May 2, 2012 Author Share Posted May 2, 2012 Baddog, I tried to experiment with the e-brake and the shudder 100% goes away... I can take a look at the Axles tomorrow. But if the axels were bent wouldn't it shake all of the time? Link to comment Share on other sites More sharing options...
TexasLegacy2.5GT Posted May 2, 2012 Author Share Posted May 2, 2012 did you bed in the brakes? ^^^Yes, I did! Link to comment Share on other sites More sharing options...
Baddog Posted May 2, 2012 Share Posted May 2, 2012 The joint could be bad. On my girl friends 92 Legacy it was due to a bad axle. I did the WRX brake setup on her car a couple weeks ago. The problem was still there until I replaced the axle. Link to comment Share on other sites More sharing options...
TexasLegacy2.5GT Posted May 2, 2012 Author Share Posted May 2, 2012 The joint could be bad. On my girl friends 92 Legacy it was due to a bad axle. I did the WRX brake setup on her car a couple weeks ago. The problem was still there until I replaced the axle. ^^^did it shudder just like mine decelerating with the foot on the brake? Link to comment Share on other sites More sharing options...
Baddog Posted May 2, 2012 Share Posted May 2, 2012 Yeah, it never vibrated while daily driving. I could even hear the axle was bad. Link to comment Share on other sites More sharing options...
wish Posted May 2, 2012 Share Posted May 2, 2012 My car has this problem too. Assumed it was the rotors. Still hoping it is. Link to comment Share on other sites More sharing options...
TexasLegacy2.5GT Posted May 2, 2012 Author Share Posted May 2, 2012 If you can feel it in the steering wheel it's up front. Bad wheel bearing? How do your axles look? Could even be shot bushings Are you talking about the steering rack bushings? Link to comment Share on other sites More sharing options...
Stang70Fastback Posted May 4, 2012 Share Posted May 4, 2012 Just to point something out: Rotors do not warp. It's actually pad material that builds up unevenly on the rotor surface (improper bedding-in of the brakes is one reason for that). Those uneven deposits are what cause the shuddering. Rotors are massively thick chunks of metal. They do not warp because even hard braking does not bring them up to a temperature where such an effect could occur. Link to comment Share on other sites More sharing options...
underground000 Posted May 4, 2012 Share Posted May 4, 2012 I just want to start from the beginning.... Where do you feel the vibration? Steering wheel, brake pedal, or seat (your butt) what was your bed in procedure?? How did you perform the bed in?? where did you buy your pads and rotor?? does the shudder go away when you push the pedal more? 5eat downshift rev match:) Powder coated wheels: completed:) Link to comment Share on other sites More sharing options...
TexasLegacy2.5GT Posted May 4, 2012 Author Share Posted May 4, 2012 I just want to start from the beginning.... Where do you feel the vibration? Steering wheel, brake pedal, or seat (your butt) what was your bed in procedure?? How did you perform the bed in?? where did you buy your pads and rotor?? does the shudder go away when you push the pedal more? ^^^Underground, the beginning: I purchased the car with the shudder already present on it. It only appears when applying the brakes decelerating from 40-30mph. I experimented with applying the hand brake to stop the car 40-30 and the shudder vanished. The steering really doesn't feel like it's shuddering more so then the brakes do. Step one: I purchased 4 OEM Subaru Rotors and replaced the front two rotors and purchased new pads from Auto Zone. After the instal I did about 6-8 stops from 60-25 to bed in the new brakes. They faded a little but not much. The exact same shudder was there present from 40-30mph. I did the brake job at my friends auto shop here in Dallas on a lift. I called him right after I was done and he said that the rear rotors could be the culprit here. I have the brand new rear rotors and pads about to go on here tomorrow at my friend's same shop. Honestly, I dont see the rear rotors really stopping this shudder at all. It really doesn't seem like the rear brakes to me. Also, reading about bent axles. I understand that the shudder is felt from those as the car is in acceleration while in gear. My LGT does not shudder at all during acceleration or while shifting. She can go 100mph smooth. Someone on here mentioned bushings...I'm going to find out this weekend 100%. I'm so annoyed by this and it needs to get fixed. Thank you for any help that you can provide. Ruben Link to comment Share on other sites More sharing options...
wish Posted May 5, 2012 Share Posted May 5, 2012 Mine doesnt do it 40-30, only if i'm going like 50mph+ and the faster i'm going the worse it is. Changing my brakes today, though. Hopefully it goes away. Link to comment Share on other sites More sharing options...
TexasLegacy2.5GT Posted May 6, 2012 Author Share Posted May 6, 2012 Wish, my car never shook after 50 when applying the brakes. Today after the well documented "H6 rear brake" upgrade my shudder going down from 40-30 completely vanished! I bedded the new brakes in and installed brand new brackets, H6 calipers, new pads, bled the brake system! No more shudder. Link to comment Share on other sites More sharing options...
Stang70Fastback Posted May 6, 2012 Share Posted May 6, 2012 wooooo! Link to comment Share on other sites More sharing options...
underground000 Posted May 6, 2012 Share Posted May 6, 2012 The handbrake uses a drum in hat instead of a brake pad, we'll see after you do the rear brakes..... if its not the brakes then it could be like you said axles - do not know much in that area... I replaced my friends rear drum shoes w/ autozone and the brake pedal vibrated like crazy until I bed them in 10 stops from 60-10 and the vibration went away 85%, did it again and it was completely gone 5eat downshift rev match:) Powder coated wheels: completed:) Link to comment Share on other sites More sharing options...
wish Posted May 6, 2012 Share Posted May 6, 2012 My shudder went away after changing my brakes today. The front rotors were fine, but the pads were worn unevenly for some reason. Rears were totally shot and rusted like crazy. Nightmare to get the rotors separated from the hubs. Link to comment Share on other sites More sharing options...
TexasLegacy2.5GT Posted May 6, 2012 Author Share Posted May 6, 2012 My shudder went away after changing my brakes today. The front rotors were fine, but the pads were worn unevenly for some reason. Rears were totally shot and rusted like crazy. Nightmare to get the rotors separated from the hubs. ^^^Without a doubt the culprit was my rear rotors! They were rusted to hell and the pads we shot. As I took off the old calipers the pads literally fell apart and on to the floor. I had to really give the rotors a good whack with the hammer about 3-4 times till she came loose. I bedded the breaks about 6-8 times down from 60-20 Link to comment Share on other sites More sharing options...
wish Posted May 6, 2012 Share Posted May 6, 2012 I gotta check today if my ebrake holds now with the new pads and rotors. The old pads were like as thin as a quarter and all rust. The old rotors were half as thin as the new ones and warped like crazy. Link to comment Share on other sites More sharing options...
TexasLegacy2.5GT Posted May 6, 2012 Author Share Posted May 6, 2012 Wish, 13 year old cars are going to need some TLC. You gotta love these beauties when they reward you back.. Link to comment Share on other sites More sharing options...
wish Posted May 6, 2012 Share Posted May 6, 2012 I just don't understand the previous owner's logic. Replaced the motor instead of doing the head gaskets and did the clutch and a few other things at the same time, but didn't touch the brakes, any of the fluids, plugs, wires, etc. And he was a mechanic. What a half-ass. Link to comment Share on other sites More sharing options...
I Donated broknindarkagain Posted May 6, 2012 I Donated Share Posted May 6, 2012 Just to point something out: Rotors do not warp. It's actually pad material that builds up unevenly on the rotor surface (improper bedding-in of the brakes is one reason for that). Those uneven deposits are what cause the shuddering. Rotors are massively thick chunks of metal. They do not warp because even hard braking does not bring them up to a temperature where such an effect could occur. You have never put a rotor on a brake lathe have you? Nearly all rotors are warped to some extent. Here are pictures of warped rotors being cut on a lathe. One is a standard lathe and one is an on the car lathe. You can see the non cut surface (shiny part) thats due to wapring of the rotor. The lathes cutting bit stays in the same spot (laterally) and works its way from the inside to the outside of the rotor. The shiny parts are where the bit did not touch the rotor due to that part being further away from the bit. While cutting rotors this can also happen if you do not put the rotor on the lathe correctly (or have a bent shaft on the lathe)....so usually when you see this while cutting rotors, you double check to verify you have the rotor set on the lathe straight. The first picture shows minor warping. This is very common and appears on almost every rotor that you would cut....especially if you do very shallow cuts over and over again until the rotor is true. This is the preferred method since it only takes off just enough metal and not too much. The goal is to keep the rotors as thick as possible. The thicker they are, the more efficiently the disipate the heat produced by braking. The second image is a more severely warped rotor. When you compare the two, you can see that there is a sudden difference as opposed to something that is gradual like the first image. When rotors are in this condition, you run more of a risk of taking off too much metal and machining them so far that they are below the discard specs by the time you are done. Warping rotors have become more and more of a problem in the recent years. Parts companies are cutting costs any way they can. They make their rotors vents and surfaces thinner now. These "light weight" rotors do not dissipate the heat of braking like they should and they sure as hell do get hot enough to warp. Take a look at the third image. http://www.geddesautomotive.co.nz/Images/brake_disc07.jpg http://forums.pelicanparts.com/uploads14/356+new_2007+10+31+200710300781237660156.jpg http://www.aa1car.com/library/2003/rotor_warning.jpg -broknindarkagain My Current Project - Click Here COME AND TAKE IT "The only thing necessary for the triumph of evil is for good men to do nothing." Link to comment Share on other sites More sharing options...
TexasLegacy2.5GT Posted May 6, 2012 Author Share Posted May 6, 2012 Stang, looks like your "no warped theory" went right out the window with Furman's last post with the photos to back it up! Thanks John! Link to comment Share on other sites More sharing options...
underground000 Posted May 6, 2012 Share Posted May 6, 2012 *also can be runout or high spots caused can be over torque lug nuts, rotor machined a little out of spec, or wheel bearing has runout, rotors too thin - min thickness - heating cooling can warp rotors -all contribute to the 'warped rotors' 5eat downshift rev match:) Powder coated wheels: completed:) Link to comment Share on other sites More sharing options...
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