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Brake shudder and small vibration when driving


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I have a 2001 Subaru Legacy Outback with 170,000 miles that is having violent shuddering problems when braking and a barely noticeable shudder when at speeds above 55-60 mph. A mechanic friend said that the R&P was broke (it was, very badly) and that the reason I only felt the shudder when braking was due to the R&P violently moving when the pads were pressing on the rotor. 

 

I replaced the R&P, both outer tie rods ends, and steering pump back in July 2016. I also recently had the transmission and axles drained and refilled in August 2016. The axles were put on December 2015. (I should mention that the R&P was an absolute Son of a Biscuit and after 2 alignments from Free Service (who I will never use again), the steering wheel is not exactly aligned.)

 

After the fix in July, the shudder is much, much, MUCH better but it is still there. I am thinking that I need to replace the rotors and pads, but the previous dealer replaced both sets of rotors and pads less than a year ago. I am not sure if driving and braking on a basically severed R&P would cause the rotors and pads to warp between October 2015 and July 2016. But the dealer is also a crook, so they rotors and pads could have not been new. 

 

The shudder when braking is mostly in the steering wheel (which shakes pretty bad), but sometimes I can feel it in the seat. My passengers say they do not feel the shudder at all. The shudder lessens as the vehicle slows and it is very rhythmic when you are almost stopped. This leads me to think that the rotors and pads are warped. But could it be the wheel hubs?

 

Any suggestions?

 

 

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I think it is a warped rotor. This often happens when the rotor is over heated. Check to see if rotor slide pins are not stuck. If stuck, the pad does not completely pull back from the rotor, when you take your foot off the brake pedal. Result is over heating the rotor, and worn brake pad.

 

This will happen on just one side of the car, and most often on the front. Usually you can feel, or detect which front side is causing the shudder. That is the brake to check out first.

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^ +1

 

Check out the front brakes and make sure everything is moving freely and nothing is frozen. But yeah rotors are most likely the issue.

By frozen, are you talking about the calipers not functioning properly?

 

And would you all suggest a certain kind or brand of rotors/brakes? Would it be better to do drilled/slotted/both or just solid ones?

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When I say frozen, usually if anything is frozen or binding it's the caliper slide pins. They get semi suck or frozen completely and as Rooster2 said, can cause the pad not to retract from the rotor and causes them to overheat etc. Also, the caliper piston can get frozen (though much less likely)

 

As for rotors, i don't have a brand I can recommend. But as for slotted and or drilled. They really aren't necessary unless you drive the car hard/race it. If you're constantly using the brake like every 5 second then yeah, maybe performance rotors. 

 

So, as far as performance rotors. Watching some videos of experts talk about performance rotors. If that's the route you choose to go. Directional provide the best heat dissipation and overall will do you the best. 

Second best for heat dissipation is slotted. As they allow a slight path or air to get in between the pad and rotor when it's spinning. 

And in terms of heat dissipation, drilled are the worst. And don't provider anything for heat (well, very minor) In fact they actually reduce stopping power (as you have a reduced surface area between the rotor and pad. The main reason racers use drilled is because they allow water to get off the rotor super quick and allow the rotor to go back to metal to pad instead of water being a barrier in there.

 

So unless you are planing on driving through huge puddles that would get the rotors soaked, drilled are pointless and you're better off seeking directional and slotted.

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Good luck! Just remember to not use ceramic pads on a vehicle that isn't supposed to have ceramic pads. Semi-matalic pads help remove heat from from the rotor, and if the vehicle wasn't designed for ceramic, that can very easily cause the overheating issue and warpage.

Not a lot of people realize that.

Ceramic pads are put on high end cars because they don't experience brake fade like semi-matalic's do

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Good luck! Just remember to not use ceramic pads on a vehicle that isn't supposed to have ceramic pads. Semi-matalic pads help remove heat from from the rotor, and if the vehicle wasn't designed for ceramic, that can very easily cause the overheating issue and warpage.

Not a lot of people realize that.

Ceramic pads are put on high end cars because they don't experience brake fade like semi-matalic's do

How would you know if the vehicle is not supposed to use ceramic pads? I have always been told to buy ceramic, so this is a first for me.

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How would you know if the vehicle is not supposed to use ceramic pads? I have always been told to buy ceramic, so this is a first for me.

I have been using ceramic pads on both my 98 and 99 OBWs for years with no issues. Go to any parts store, ask for brake pads, and ceramics are offered to fit my Subarus.

 

Maybe ceramics are not advised for competition cars that would need heat removal, but for the average "driver" car, ceramics should be just fine.

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Akebono ceramic have been delivered on new soobs for a decade or 2. Semi-metallic are also a decent choice I think.

 

I'd avoid drilled or slotted (except maybe for a dedicated or occasional race vehicle) as modern pads don't outgas as much.

 

Subaru rotors are good and folks should try to keep them until damaged or worn down to the minimum thickness stamped on them. When it becomes time for me to get rotors, I will buy Centric.

 

Centric PosiQuiet Ceramic pads are what I run on my OBW. Other name brand ceramic pads should be fine as well. Stay away from 'economy' pads.

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I took my subaru to my mechanic friend and got the rotors turned for $15 a pop + labor. He said the brakes looked brand new. So problem fixed for $105!! Wooh!!

 

I am guessing that when the dealer relpaced the rotors and pads, they did not form them to each other. It probabaly sat untill every test driver slammed on the brakes.

Edited by maroon_subi
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