steering wobble when braking returns-help

talos · Mar 13, 2013

A while back I posted about a problem with my steering shaking under braking. ( I have 04 brembos on 02 bugeye) It was quickly discovered that I had not bedded my pads properly. The rotors got hot spots and blah blah blah they were toast. I purchased a set of DBAs and some new pads and bedded them properly. Followed the instructions and everything went exactly as described. Brakes worked great and the shake went away. Its been about 4 months and the shaking is coming back. I haven't done much more than drive to and from work which is from midtown to little 5 on surface roads so I definitely haven't been abusing them. Ideas and suggestions please

bixs · Mar 13, 2013

Bed them again. From what I understand, the pad material that is transferred is just going to get scraped off if you are doing a lot of colder slower braking. Seems to happen to me all the time with how much I DD and the pads I use.

I reached the conclusion by reading about the race pads I had on my STI. It was recommended to me to leave them on while DD'ing for a day or two to 'de-bed' the pad, then swap and bed the street pads.

integroid · Mar 13, 2013

Or quit braking like a woman and stomp on the brakes a few times. What kind of pads?

talos · Mar 13, 2013

bixs said: ↑

Bed them again. From what I understand, the pad material that is transferred is just going to get scraped off if you are doing a lot of colder slower braking. Seems to happen to me all the time with how much I DD and the pads I use.

I reached the conclusion by reading about the race pads I had on my STI. It was recommended to me to leave them on while DD'ing for a day or two to 'de-bed' the pad, then swap and bed the street pads.
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Definetly worth a try, do you have to do anything to them first or just go through the process again?

talos · Mar 13, 2013

integroid said: ↑

Or quit braking like a woman and stomp on the brakes a few times. What kind of pads?
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I have stoptechs. Unfortunately, my commute doesn't really lend itself to aggressive driving :/ Plenty of cops, people and no speed limits higher than 35mph. Its a good thing its only 15 mins.

wagunz_pwn · Mar 13, 2013

I have the exact same issues. Pads get below half and the death wobble/shake returns.

integroid · Mar 13, 2013

Stoptech pads suck. Get some real man pads Carbotechs or Hawk.

Jake · Mar 13, 2013

i liked my EBC greens, not track/race pads by any means, but good aggressive street pads. then again, that's been years and everyone seems to love the hawks

talos · Mar 13, 2013

Yeah, this is definitely the last time I use the stoptechs. I'll probably get hawk hps in the future. Heard nothing but good things a out them. Gonna try the re-bedding process tomorrow and hopefully that'll work for the time being.

bixs · Mar 14, 2013

talos said: ↑

Definetly worth a try, do you have to do anything to them first or just go through the process again?
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nope just followed the same procedure I did the first time around

nygiant · Mar 14, 2013

I have stoptech pads that were put on in october. Like you, I've got bad shake/vibration under braking and it drives me nuts. I know it's my fault for not bedding them in properly, but if this isnt an isolated issue then I will just ditch the pads. Are the stoptechs for sure the issue? Guess thats what I get for going with the least expensive "performance" pad I could find.

Here's stoptech's take on warped rotors, vibration, and pad material imprinted onto the disc

Myth # 1 – BRAKE JUDDER AND VIBRATION IS CAUSED BY DISCS THAT HAVE BEEN WARPED FROM EXESSIVE HEAT.

The term "warped brake disc" has been in common use in motor racing for decades. When a driver reports a vibration under hard braking, inexperienced crews, after checking for (and not finding) cracks often attribute the vibration to "warped discs". They then measure the disc thickness in various places, find significant variation and the diagnosis is cast in stone.

When disc brakes for high performance cars arrived on the scene we began to hear of "warped brake discs" on road going cars, with the same analyses and diagnoses. Typically, the discs are resurfaced to cure the problem and, equally typically, after a relatively short time the roughness or vibration comes back. Brake roughness has caused a significant number of cars to be bought back by their manufacturers under the "lemon laws". This has been going on for decades now - and, like most things that we have cast in stone, the diagnoses are wrong.

With one qualifier, presuming that the hub and wheel flange are flat and in good condition and that the wheel bolts or hat mounting hardware is in good condition, installed correctly and tightened uniformly and in the correct order to the recommended torque specification, in more than 40 years of professional racing, including the Shelby/Ford GT 40s – one of the most intense brake development program in history - I have never seen a warped brake disc. I have seen lots of cracked discs, (FIGURE 1) discs that had turned into shallow cones at operating temperature because they were mounted rigidly to their attachment bells or top hats, (FIGURE 2) a few where the friction surface had collapsed in the area between straight radial interior vanes, (FIGURE 3) and an untold number of discs with pad material unevenly deposited on the friction surfaces - sometimes visible and more often not. (FIGURE 4)

In fact every case of "warped brake disc" that I have investigated, whether on a racing car or a street car, has turned out to be friction pad material transferred unevenly to the surface of the disc. This uneven deposition results in thickness variation (TV) or run-out due to hot spotting that occurred at elevated temperatures.

In order to understand what is happening here, we will briefly investigate the nature of the stopping power of the disc brake system.

THE NATURE OF BRAKING FRICTION
Friction is the mechanism that converts dynamic energy into heat. Just as there are two sorts of friction between the tire and the road surface (mechanical gripping of road surface irregularities by the elastic tire compound and transient molecular adhesion between the rubber and the road in which rubber is transferred to the road surface), so there are two very different sorts of braking friction - abrasive friction and adherent friction. Abrasive friction involves the breaking of the crystalline bonds of both the pad material and the cast iron of the disc. The breaking of these bonds generates the heat of friction. In abrasive friction, the bonds between crystals of the pad material (and, to a lesser extent, the disc material) are permanently broken. The harder material wears the softer away (hopefully the disc wears the pad). Pads that function primarily by abrasion have a high wear rate and tend to fade at high temperatures. When these pads reach their effective temperature limit, they will transfer pad material onto the disc face in a random and uneven pattern. It is this "pick up" on the disc face that both causes the thickness variation measured by the technicians and the roughness or vibration under the brakes reported by the drivers.
With adherent friction, some of the pad material diffuses across the interface between the pad and the disc and forms a very thin, uniform layer of pad material on the surface of the disc. As the friction surfaces of both disc and pad then comprise basically the same material, material can now cross the interface in both directions and the bonds break and reform. In fact, with adherent friction between pad and disc, the bonds between pad material and the deposits on the disc are transient in nature - they are continually being broken and some of them are continually reforming.

There is no such thing as pure abrasive or pure adherent friction in braking. With many contemporary pad formulas, the pad material must be abrasive enough to keep the disc surface smooth and clean. As the material can cross the interface, the layer on the disc is constantly renewed and kept uniform - again until the temperature limit of the pad has been exceeded or if the pad and the disc have not been bedded-in completely or properly. In the latter case, if a uniform layer of pad material transferred onto the disc face has not been established during bedding or break-in, spot or uncontrolled transfer of the material can occur when operating at high temperatures. The organic and semi-metallic pads of the past were more abrasive than adherent and were severely temperature limited. All of the current generation of "metallic carbon", racing pads utilize mainly adherent technology as do many of the high end street car pads and they are temperature stable over a much higher range. Unfortunately, there is no free lunch and the ultra high temperature racing pads are ineffective at the low temperatures typically experienced in street use.

Therefore - there is no such thing as an ideal "all around" brake pad. The friction material that is quiet and functions well at relatively low temperatures around town will not stop the car that is driven hard. If you attempt to drive many cars hard with the OEM pads, you will experience pad fade, friction material transfer and fluid boiling - end of discussion. The true racing pad, used under normal conditions will be noisy and will not work well at low temperatures around town.

Ideally, in order to avoid either putting up with squealing brakes that will not stop the car well around town or with pad fade on the track or coming down the mountain at speed, we should change pads before indulging in vigorous automotive exercise. No one does. The question remains, what pads should be used in high performance street cars - relatively low temperature street pads or high temperature race pads? Strangely enough, in my opinion, the answer is a high performance street pad with good low temperature characteristics. The reason is simple: If we are driving really hard and begin to run into trouble, either with pad fade or boiling fluid (or both), the condition(s) comes on gradually enough to allow us to simply modify our driving style to compensate. On the other hand, should an emergency occur when the brakes are cold, the high temperature pad is simply not going to stop the car. As an example, during the mid 1960s, those of us at Shelby American did not drive GT 350 or GT 500 Mustangs as company cars simply because they were equipped with Raybestos M-19 racing pads and none of our wives could push on the brake pedal hard enough to stop the car in normal driving.
Regardless of pad composition, if both disc and pad are not properly broken in, material transfer between the two materials can take place in a random fashion - resulting is uneven deposits and vibration under braking. Similarly, even if the brakes are properly broken, if, when they are very hot or following a single long stop from high speed, the brakes are kept applied after the vehicle comes to a complete stop it is possible to leave a telltale deposit behind that looks like the outline of a pad. This kind of deposit is called pad imprinting and looks like the pad was inked for printing like a stamp and then set on the disc face. It is possible to see the perfect outline of the pad on the disc. (FIGURE 5)

It gets worse. Cast iron is an alloy of iron and silicon in solution interspersed with particles of carbon. At elevated temperatures, inclusions of carbides begin to form in the matrix. In the case of the brake disk, any uneven deposits - standing proud of the disc surface - become hotter than the surrounding metal. Every time that the leading edge of one of the deposits rotates into contact with the pad, the local temperature increases. When this local temperature reaches around 1200 or 1300 degrees F. the cast iron under the deposit begins to transform into cementite (an iron carbide in which three atoms of iron combine with one atom of carbon). Cementite is very hard, very abrasive and is a poor heat sink. If severe use continues the system will enter a self-defeating spiral - the amount and depth of the cementite increases with increasing temperature and so does the brake roughness. Drat!
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nygiant · Mar 14, 2013

continued...

PREVENTION
There is only one way to prevent this sort of thing - following proper break in procedures for both pad and disc and use the correct pad for your driving style and conditions. All high performance after market discs and pads should come with both installation and break in instructions. The procedures are very similar between manufacturers. With respect to the pads, the bonding resins must be burned off relatively slowly to avoid both fade and uneven deposits. The procedure is several stops of increasing severity with a brief cooling period between them. After the last stop, the system should be allowed to cool to ambient temperature. Typically, a series of ten increasingly hard stops from 60mph to 5 mph with normal acceleration in between should get the job done for a high performance street pad. During pad or disc break-in, do not come to a complete stop, so plan where and when you do this procedure with care and concern for yourself and the safety of others. If you come to a complete stop before the break-in process is completed there is the chance for non-uniform pad material transfer or pad imprinting to take place and the results will be what the whole process is trying to avoid. Game over.

In terms of stop severity, an ABS active stop would typically be around 0.9 G’s and above, depending on the vehicle. What you want to do is stop at a rate around 0.7 to 0.9 G's. That is a deceleration rate near but below lock up or ABS intervention. You should begin to smell pads at the 5th to 7th stop and the smell should diminish before the last stop. A powdery gray area will become visible on the edge of the pad (actually the edge of the friction material in contact with the disc - not the backing plate) where the paint and resins of the pad are burning off. When the gray area on the edges of the pads are about 1/8" deep, the pad is bedded.

For a race pad, typically four 80mph to 5 and two 100mph to 5, depending on the pad, will also be necessary to raise the system temperatures during break-in to the range that the pad material was designed to operate at. Hence, the higher temperature material can establish its layer completely and uniformly on the disc surface.

Fortunately the procedure is also good for the discs and will relieve any residual thermal stresses left over from the casting process (all discs should be thermally stress relieved as one of the last manufacturing processes) and will transfer the smooth layer of pad material onto the disc. If possible, new discs should be bedded with used pads of the same compound that will be used going forward. Again, heat should be put into the system gradually - increasingly hard stops with cool off time in between. Part of the idea is to avoid prolonged contact between pad and disc. With abrasive pads (which should not be used on high performance cars) the disc can be considered bedded when the friction surfaces have attained an even blue color. With the carbon metallic type pads, bedding is complete when the friction surfaces of the disc are a consistent gray or black. In any case, the discoloration of a completely broken in disc will be complete and uniform.

Depending upon the friction compound, easy use of the brakes for an extended period may lead to the removal of the transfer layer on the discs by the abrasive action of the pads. When we are going to exercise a car that has seen easy brake use for a while, a partial re-bedding process will prevent uneven pick up.

The driver can feel a 0.0004" deposit or TV on the disc. 0.001" is annoying. More than that becomes a real pain. When deposit are present, by having isolated regions that are proud of the surface and running much hotter than their neighbors, cementite inevitably forms and the local wear characteristics change which results in ever increasing TV and roughness.

Other than proper break in, as mentioned above, never leave your foot on the brake pedal after you have used the brakes hard. This is not usually a problem on public roads simply because, under normal conditions, the brakes have time to cool before you bring the car to a stop (unless, like me, you live at the bottom of a long steep hill). In any kind of racing, including autocross and "driving days" it is crucial. Regardless of friction material, clamping the pads to a hot stationary disc will result in material transfer and discernible "brake roughness". What is worse, the pad will leave the telltale imprint or outline on the disc and your sin will be visible to all and sundry.

The obvious question now is "is there a "cure" for discs with uneven friction material deposits?" The answer is a conditional yes. If the vibration has just started, the chances are that the temperature has never reached the point where cementite begins to form. In this case, simply fitting a set of good "semi-metallic" pads and using them hard (after bedding) may well remove the deposits and restore the system to normal operation but with upgraded pads. If only a small amount of material has been transferred i.e. if the vibration is just starting, vigorous scrubbing with garnet paper may remove the deposit. As many deposits are not visible, scrub the entire friction surfaces thoroughly. Do not use regular sand paper or emery cloth as the aluminum oxide abrasive material will permeate the cast iron surface and make the condition worse. Do not bead blast or sand blast the discs for the same reason.

The only fix for extensive uneven deposits involves dismounting the discs and having them Blanchard ground - not expensive, but inconvenient at best. A newly ground disc will require the same sort of bedding in process as a new disc. The trouble with this procedure is that if the grinding does not remove all of the cementite inclusions, as the disc wears the hard cementite will stand proud of the relatively soft disc and the thermal spiral starts over again. Unfortunately, the cementite is invisible to the naked eye.

Taking time to properly bed your braking system pays big dividends but, as with most sins, a repeat of the behavior that caused the trouble will bring it right back.
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talos · Mar 14, 2013

nygiant - I read through that same thing when I had It happen to me the first time. In that instance I also hadn't bedded them in properly. I figured shame on me, got the DBA rotors and another set of stoptechs, and this time made sure I did everything right. In about the same amount of time as it took the first time, the shudder came back. The only thing that didn't change in the setup was the pads. I think the article makes sense but I kinda feel like its a way for stoptech to cover themselves and say its you not them. Hearing that a number of other members are having the same issues definitely seals the deal. No more stoptechs for me.

This problem could be a result of the daily driving on performance street pads that may be a little too performance oriented. Regardless, I've had an MR2 Turbo and an s2000 and always ran performance street pads on both (ebc yellows and hawk hps respectively) and never had a single issue.

update on the situation - The re-bedding process didn't give much result. I'll just have to resurface the rotors and put some hawks on there.

b reel · Mar 15, 2013

so 11yo car... 11yo calipers, tie-rods, ball joints?

talos · Mar 15, 2013

b reel said: ↑

so 11yo car... 11yo calipers, tie-rods, ball joints?
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I just did the sti swap last year, new ball joints, checked the tie rods on sti rack and checked pretty much everything else connected to the steering. Brandon and Wess have also gone over it. These things crossed my mind when this all happened the first time. However, the problem only starts after 4 months on the new pad/rotor setup. (I put new pads and rotors on when I did the swap too) The problem has only ever presented itself under medium or light breaking from 40mph or more. If I clamp em down it doesn't shudder. Makes off ramps a royal PITA once it gets bad.

The only other culprit I can think of is that the calipers need rebuilding but the fact that it takes so long to happen makes me doubt it. Plus I don't feel it in the brake pedal at all.

nygiant · Mar 15, 2013

talos said: ↑

I just did the sti swap last year, new ball joints, checked the tie rods on sti rack and checked pretty much everything else connected to the steering. Brandon and Wess have also gone over it. These things crossed my mind when this all happened the first time. However, the problem only starts after 4 months on the new pad/rotor setup. (I put new pads and rotors on when I did the swap too) The problem has only ever presented itself under medium or light breaking from 40mph or more. If I clamp em down it doesn't shudder. Makes off ramps a royal PITA once it gets bad.

The only other culprit I can think of is that the calipers need rebuilding but the fact that it takes so long to happen makes me doubt it. Plus I don't feel it in the brake pedal at all.
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talos, interesting you say that because my shudder STARTS AT EXACTLY 40mph, and continues on down to 0.
since it seems we're pretty much concluding it is indeed the stoptechs as we're all in the same boat, I will ditch them as well and pick up some hawk hps

Matto357 · Mar 15, 2013

I have stoptechs and haven't had any problems with them whatsoever. In fact, I'm pretty sure I have that whole pad imprint thing going on. Was at a track day, overboosted pretty bad, pulled off to clear the CEL and wasn't thinking about having my foot on the brakes as long as I had them. I still don't have any shudder.

integroid · Mar 15, 2013

Seriously guys, stop braking like a little girl and stomp on the brakes a few times a week.

nygiant · Mar 15, 2013

integroid said: ↑

Seriously guys, stop braking like a little girl and stomp on the brakes a few times a week.
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but having that progressive snapshot in my car for a year and a half has trained me to brake like a little bitch :|
plus easy accelerating and braking saves gas :dunno

integroid · Mar 15, 2013

nygiant said: ↑

but having that progressive snapshot in my car for a year and a half has trained me to brake like a little bitch :|
plus easy accelerating and braking saves gas :dunno
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How does easy braking save gas?

nygiant · Mar 15, 2013

integroid said: ↑

How does easy braking save gas?
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i dunno. the tv told me that

Matt · Mar 15, 2013

Must have been Clark Howard. :|

b reel · Mar 15, 2013

integroid said: ↑

How does easy baking save gas?
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not using the lighter as often?

talos · Mar 15, 2013

Matto357 said: ↑

I have stoptechs and haven't had any problems with them whatsoever. In fact, I'm pretty sure I have that whole pad imprint thing going on. Was at a track day, overboosted pretty bad, pulled off to clear the CEL and wasn't thinking about having my foot on the brakes as long as I had them. I still don't have any shudder.
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From what I am beginning to understand about these pads, if you are tracking your car you're probably not gonna have the same problem as those of us that are daily driving and not getting them heated up regularly. They are probably just too aggressive for normal daily driving.

b reel · Mar 15, 2013

they'll glaze over and chatter on a DD. if you have a good set of rotors with proper slotting all you need to do is stab the brakes every once in a while to clean them off. Personally I think it's a waste of money running aggressive pads on a daily unless you drive like an ass. The smart ones have a set of normal pads for DD and a good set for Mtn runs and track days.

nygiant · Mar 15, 2013

so what are normal pads? I'd still like to be able to brake well when I do drive like an ass with my DD

nygiant · Mar 15, 2013

integroid said: ↑

Seriously guys, stop braking like a little girl and stomp on the brakes a few times a week.
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I tried this starting today and it made the issue much worse...now I remember why I've been doing easy braking - because stomping on the brakes causes the car to shake to shit

b reel · Mar 16, 2013

depends if OEM or aftermarket calipers. I've run Premium Advanced, NAPA or whatever was on sale and never really had an issue.

nygiant · Mar 16, 2013

i've got oem calipers. i might just get the subaru oem pads that i had on the car before...i actually liked them

b reel · Mar 16, 2013

post up pics of the pads you are running now

nygiant · Mar 16, 2013

b reel · Mar 16, 2013

ok now pictures of the actual pads from your car

2010subiefoz · Mar 16, 2013

talos said: ↑

I have stoptechs. Unfortunately, my commute doesn't really lend itself to aggressive driving :/ Plenty of cops, people and no speed limits higher than 35mph. Its a good thing its only 15 mins.
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Yeah,

I hate my stop techs. They put way to much dust on my wheels. Secondly, they don't stop any better than the stock ones.

Sent from my mind using ninja telepathy.

KGraska · Mar 19, 2013

I have DBA4000 rotors with those Stoptech pads installed for about 3 months now and I'm starting to get shaking and vibration similar to what you describe.

I was scared that I ruined my new rotors and somehow warped them while bedding the pads. I'm going to try some different pads and see if that fixes anything.

talos · Mar 20, 2013

KGraska said: ↑

I have DBA4000 rotors with those Stoptech pads installed for about 3 months now and I'm starting to get shaking and vibration similar to what you describe.

I was scared that I ruined my new rotors and somehow warped them while bedding the pads. I'm going to try some different pads and see if that fixes anything.
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^^Do you daily drive like the rest of us having the problem? Any track or mountain runs?

Let me know what you go with and how they work out. Are you gonna resurface the rotors or just run the new pads.

Does anyone who does mostly commuting on their brembos have a street/performance pad they have had good experiences with?

integroid · Mar 20, 2013

talos said: ↑

Does anyone who does mostly commuting on their brembos have a street/performance pad they have had good experiences with?
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I use Hawk HPS or HP+ pads but I also drive it like I stole it so never had problems with car shaking under braking.

KGraska · Mar 23, 2013

talos said: ↑

^^Do you daily drive like the rest of us having the problem? Any track or mountain runs?

Let me know what you go with and how they work out. Are you gonna resurface the rotors or just run the new pads.

Does anyone who does mostly commuting on their brembos have a street/performance pad they have had good experiences with?
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I DD for the most part but I drive pretty spirited. If I use the brakes a lot and heat them up they seem to be better but after some normal driving they are back to the usual shaking.

I haven't decided on new pads yet, probably some hawk HPS. The rotors are slotted so I doubt I'll be able to resurface them. They are only a few months old.

b reel · Mar 23, 2013

being slotted doesn't matter when resurfacing.

talos · Mar 23, 2013

KGraska said: ↑

I DD for the most part but I drive pretty spirited. If I use the brakes a lot and heat them up they seem to be better but after some normal driving they are back to the usual shaking.

I haven't decided on new pads yet, probably some hawk HPS. The rotors are slotted so I doubt I'll be able to resurface them. They are only a few months old.
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I'm on the exact same page as you. I have been trying to get some heat in my stoptechs more often lately and its helped some but isn't good enough to call it fixed. I was thinking resurface and hawks as well.

I have been tempted to try a set of auto parts store pads to see if they are worth a crap but the off chance that I make it up to the mountains or to an autocross is keeping me from going that route. I wouldn't worry about them in dd duty but don't trust them when performance is an issue.

KGraska · May 9, 2013

Well I went ahead and had my rotors resurfaced by the guys at AllPro. I left the stoptech pads on to see if the shaking was better or if I was gonna have to change pads too.

After a day of driving around to test, my brakes are perfect. The pads feel so much better now and actually stop the car a lot quicker. I was quick to blame the pads but i'm very happy with them so far.

integroid · May 9, 2013

It will come back.....Just give it some time

You really need to brake hard a few times a week to prevent the shakes.

talos · May 9, 2013

integroid said: ↑

It will come back.....Just give it some time

You really need to brake hard a few times a week to prevent the shakes.
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^^What he said. I resurfaced mine the first time around and it came back.

I am installing Hawk HPS pads and resurfacing the rotors this weekend. Fingers crossed I can have a shake free drive from now on.

KGraska · May 10, 2013

talos said: ↑

^^What he said. I resurfaced mine the first time around and it came back.

I am installing Hawk HPS pads and resurfacing the rotors this weekend. Fingers crossed I can have a shake free drive from now on.
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Was this with StopTech pads?

Brandon from AllPro said he recommends the stoptech over the HPS. Thats pretty much what I've read from my research online too. I didnt want to buy pads that were double the price of stoptechs with half the braking performance.

talos · May 10, 2013

Yes, the only pads I've had on my car since the 6 speed/ Brembo swap is Stoptechs. Two sets actually because I replaced the barely worn first set when I installed the DBA slotted rotors. I have tried to fix the problem with resurfacing and new rotors. The only variables that haven't changed are the pads and my driving. Since I have never had a problem like this with any other car and have been driving for the better part of 15 years we are gonna rule out the fact that its the driving habits.

The stopping power is not the issue, the Stoptechs are an aggressive, more track oriented pad than the Hawks so they most likely do have better performance at the limits. In the mountains or on the track the Stoptechs probably have a slight edge over the Hawks. Though with the Brembos on our cars we could probably put Duralast pads on and still out-stop most cars in normal situations. The Hawks are (presumably) a better compromise between daily drivability and an adequate autocross/mountain run performance pad. It really just depends on where your driving habits and priorities for the car lye in the scale of daily driving to all out performance. I think a nifty chart would be helpful here

Where people are having issues is in daily driving the Stoptechs and not running them through heat cycles causing them to essentially de-bed and cause a shudder under normal braking. If you plan on driving hard and heating your brakes up regularly then the Stoptechs will probably be fine. However, since you have already had the issue once, you will probably encounter it again unless you change your driving habits.

I will have the Hawks on with resurfaced rotors (only 6 months old DBAs) tomorrow. I don't plan on changing my driving so if all is good in a few months I think we will have a pretty definitive answer to what's causing the problems.

bluedestiny · May 15, 2013

i have seen a shudder problem develop with underinflated front tires cupping, swapped fronts to rear, corrected pressure, and it went away; this was our FR 2 wd Tacoma Prerunner

integroid · May 15, 2013

talos said: ↑

Yes, the only pads I've had on my car since the 6 speed/ Brembo swap is Stoptechs. Two sets actually because I replaced the barely worn first set when I installed the DBA slotted rotors. I have tried to fix the problem with resurfacing and new rotors. The only variables that haven't changed are the pads and my driving. Since I have never had a problem like this with any other car and have been driving for the better part of 15 years we are gonna rule out the fact that its the driving habits.

The stopping power is not the issue, the Stoptechs are an aggressive, more track oriented pad than the Hawks so they most likely do have better performance at the limits. In the mountains or on the track the Stoptechs probably have a slight edge over the Hawks. Though with the Brembos on our cars we could probably put Duralast pads on and still out-stop most cars in normal situations. The Hawks are (presumably) a better compromise between daily drivability and an adequate autocross/mountain run performance pad. It really just depends on where your driving habits and priorities for the car lye in the scale of daily driving to all out performance. I think a nifty chart would be helpful here

Where people are having issues is in daily driving the Stoptechs and not running them through heat cycles causing them to essentially de-bed and cause a shudder under normal braking. If you plan on driving hard and heating your brakes up regularly then the Stoptechs will probably be fine. However, since you have already had the issue once, you will probably encounter it again unless you change your driving habits.

I will have the Hawks on with resurfaced rotors (only 6 months old DBAs) tomorrow. I don't plan on changing my driving so if all is good in a few months I think we will have a pretty definitive answer to what's causing the problems.
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The problem is you are using an aggressive pad but not braking aggressively. This is leaving deposits on the rotors over time and that is why you are getting the shudder. Like I have said since you started this thread, stop driving it like a grandma and do some aggressive braking a few times each time you drive the car.

J_P · May 15, 2013

If you don't mind cleaning your wheels both the Hawk HP+ and the factory Brembos won't make noise if you brake hard. Personally, I did not like the HPS pads on this car, but had good experiences with slower cars (civic). I'm going to try the Ferodo DS2500s next.

GL

crazyazn · May 15, 2013

I agree with what everyone is saying, if your pads are aggressive, a few hard stops are actually great for them and the rotors. Me being on the hp+'s its almost a routine to have a hard stop or two when I leave my neighborhood, gets them up to temp and nice and grabby.

Also keeping the calipers/wheels washed helps a ton with the noise, SONAX makes this task a lot easier with dusty pads.

Also for noise...
Get a jar of the brake grease, not the little bitch packets, and seriously get a decent coating on the shims, and for me, a nice bit on the 'guide pins' killed the really high pitched low speed squeal I had.

talos · May 15, 2013

J_P said: ↑

If you don't mind cleaning your wheels both the Hawk HP+ and the factory Brembos won't make noise if you brake hard. Personally, I did not like the HPS pads on this car, but had good experiences with slower cars (civic). I'm going to try the Ferodo DS2500s next.

GL
Click to expand...

Out of curiosity, what didn't you like about the hps pads. Just put them on, wondering what I'm in for.

KGraska · Jun 8, 2013

Talos, what do you think about your new pads?

After having my rotors resurfaced a month ago these StopTech pads are causing shaking again and its driving me nuts. I have been making very aggressive stops every time I drive the car and it really isn't helping. I have great braking performance but it only lasts 2 weeks until the shaking comes back. The only way to avoid the shaking is to stop HARD every time. Which is great for my pads but not for my neck...

What are good DD pads for use on a WRX with 4pot/2pot Red Calipers? I have DBA 4000 Slotted Rotors btw

These stoptechs have got to go

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