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Discussion Starter · #1 ·
I love my STi but this car is simply full of noises.

On Friday I finally got my new Power Slot slotted rotors in at all four corners plus a brand new set of Hawk HPS. I also got my rear struts replaced under warranty from SOA so I was happy thinking my car was finally going to be noise free for at least a little while. :lol: The rear struts were clunking and creaking like nothing I'v heard in a car before.

The first few days with the new brakes were quite good, although they weren't biting hard and I was being as gentle as possible during the break-in phase. On Sunday when I was leaving a giant local import meet (http://www.imagestation.com/album/?id=2102498667) I noticed almost immedietly a knocking sound from what I *think* is from the front of the car.

If I'm slowing down to a stop it's kinda like... thud... thud... thud... thud..... but if I'm going slight faster it's almost like thud.thud.thud. You can replace "thud" with "knock" if you want. I'v done a quick inspection and everything looks tight and there are no clearance issues anywhere... so this is a little perplexing. It doesn't seem to be affecting braking itself, which is starting to improve now after 300KM but it's something I'd like to address.

Now, it's only when I'm braking, far more obvious at low speeds but not always as obvious as at other times (no consistency).

Any ideas or suggestions? Thanks all!
 

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yea, the correct way to break pads in is to kinda to beat on them. a couple stops from 60-10 and 80-10 then let them cool then do it again (thats a very brief description). you should def give this page a read

http://www.stoptech.com/tech_info/tech_white_papers.shtml

although, i doubt that the way you broke in your pads are causing the knock. it could be warped rotors, but im not sure.


edit:

now that i actually just read the link i provided, it sounds like break in was your problem, and you probably unevenly distributed pad material on your rotors.
 

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Discussion Starter · #4 ·
Frick, this is annoying. I followed the break-in/bed-in procedure to the T..... and even confirmed this by aligning myself with the suggestions provided by both Power Slot and Hawk.

I also find it weird that everything was perfect until I left the above mentioned meet.

Thanks for the replies guys.
 

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I use Carbotech break in procedures, every time. I have yet to be disappointed.

Six times on the brakes, hard from 60mph to 30mph. Then six times from 60mph to 0, although I keep the car rolling just a bit to avoid getting uneven pad distribution on the rotor.

I do this all quickly, and give the brakes no time to cool off. The pads need to be hot to leave material on the rotor.

After I'm done I drive around for 10-15 minutes to let everything cool before I park the cark.
 

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Discussion Starter · #6 ·
Well, I just went out and partially repeated my early bed-in procedure. I did three 60-20 stops and the brakes are begining to bite VERY nicely!!! :)

So I decided to head for a quick, 15 minute spin around just to give them a little light use and INSTANTLY the knocking came back worse than ever. I'm almost certain it's coming from the front right of the car but I'm not sure what it is.

Now, I didn't use the factory shims/metal plates with the Hawk pads... should I have?
 

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For some reason I want to say that I remember hearing about this happening with other people and Powerslot rotors... I think I'll never purchase a set.

In the future I'd like to recommend Carbotech if you want inexpensive brake rotors. They don't sell junk, and they're priced quite reasonably at about $160 each.
 

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Discussion Starter · #8 ·
...so a week later and things really haven't changed. The rotors at all four corners seem fine and I can't see any "deposits" on the rotors that would suggest they were poorly broken in... plus, everything looks tight so I'm at a total loss for what could be causing the knocking sound.

GRRRRR.
 

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Discussion Starter · #9 ·
...and so it continues. The knocking is very, very evident at the front end of the car but braking isn't actually affected at all. The sound is ROTATIONAL in that it's frequency is dictated by the speed of the car when I am applying the brakes.

So if I'm driving quickly and hit the breaks it's like, "KNOCK, KNOCK, KNOCK...." ...whereas if I'm slowly to a stop and I'm applying a lot of pressure or a moderate amount it's more like, "KNOCK..... KNOCK...... KNOCK......."

I pulled off all of the wheels and inspected the rotors and pad placement. Everything is tight and everything seems fine. All of the suspension components are locked down tight.

Any LAST suggestions before I give up and take it to the dealership??!?!?

Thanks guys.
 

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Sunfighter said:
...and so it continues. The knocking is very, very evident at the front end of the car but braking isn't actually affected at all. The sound is ROTATIONAL in that it's frequency is dictated by the speed of the car when I am applying the brakes.

So if I'm driving quickly and hit the breaks it's like, "KNOCK, KNOCK, KNOCK...." ...whereas if I'm slowly to a stop and I'm applying a lot of pressure or a moderate amount it's more like, "KNOCK..... KNOCK...... KNOCK......."

I pulled off all of the wheels and inspected the rotors and pad placement. Everything is tight and everything seems fine. All of the suspension components are locked down tight.

Any LAST suggestions before I give up and take it to the dealership??!?!?

Thanks guys.
Do you have digital calipers? You could check to make sure the rotors aren't warped. The hawk's do make some noise for me, but it is only when they shift slightly - like backing up or parking etc. You should use one shim on the front pads, but I doubt that would cause the issue you are describing.
 

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DoubleURX said:
Have you ruled out a bad wheel bearing? I find it odd that your only getting the noise in one corner.
That's a good point. Also, have you torqued all your lug nuts properly? 67ft-lbs and in a star pattern...
 

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Discussion Starter · #13 ·
Interestingly, I don't get any of the noises that other people have experienced with the Hawks (clunking when starting, etc.). Power Slot has been talking to me via email and have thrown some suggestions my way.... I can't help think that it might be a bad hub/bearing. My alignment is certainly off a bit, but I'v been timid about getting the alignment done until I'v actually gotten this issue solved in case I keep having to tear things apart....

Thanks for the responses guys.
 

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Discussion Starter · #14 ·
......hmmmm

Hey guys,

Well I finally got frustrated with not being able to figure this out and I took the car to the dealership since I needed an oil change anyways.

I dropped it off in the morning and came back at about 5pm to pick it up. The lady who runs the service department came over and told me my car was "weird," and explained that despite the techs working on my car the entire day (they did!) they could not find the source of the problem. During the course of the day, they swapped out almost every component from my front end, including axels, etc., in an effort to track down where the knocking sound was coming from. They took apart the brakes and noted that the rotors were all mint and that the break-in/bed-in process appeared to have gone perfectly.

So I need to give SERIOUS props to Saunders Subaru in Victoria, B.C., for their efforts. They worked all day on my car, charged me nothing for their efforts, and gave me my car back with the promise that they were going to do all they could to research the problem and find me a quick solution!!! Now that is service, despite the fact that they are working on a car sporting aftermarket springs, rotors and pads. The techs were awesome and brought me into the shop to show me what they had done, what they thought it may have been and laid out a plan to get things resolved as quickly as possible.

As it stands, they have not attempted to swap out the hubs/bearings or rotors to see if that fixes things as they did not have those parts on hand. But given that the rotors are all in mint condition it's doubtful that they are causing the problem. The techs also found that the loud knocking/banging sound is coming exclusively from the front driver's side of the car and they admitted themselves that it is "bad..." but not a safety concern.

Anyways, just an update incase anybody else ever experiences this and just some appreciation for the service guys at my dealership! :)
 

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make sure your lugs are full torqued to spec, as this can cause the precise problem

Also, pull the pads out and check the corners - if they are knicked up at all, the pad will rock back and forth causing this noise.

Also, make sure the rotors are installed the right way and no spinning backwards
 

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Being another 04 owner I am going to throw some weight into the wheel bearing issue. If you have done any sort of tracking or autox you might be victim to knock back. Ive found a lot of people do not know what this is and are startled by the noise it creates.

It is a HUGE problem with the 04s and the easiest way to kill it is the 05 hub swap. I replied to your PM you just sent me with a few questions. For additional info check out my journal: the 2004.5 STi hub swap is complete!

Granted it could be another problem entirely (and financially, I hope it is for you). Ive never used those rotors before nor have I have I ever driven your car :D
 

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Also, another bit to consider...Its small so perhaps you have overlooked it. How's the endlink in that corner? Once upon a time one of my endlinks in the rear was quite loose and I had a knocking that sounded very similar to strut clunk...turned out to be the endlink :p
 

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Mykl, how did you get your hands on carbotech rotors?? I heard about these but I can't find them on their website? Also, are they slotted or just plain rotors.

I love the carbo tech pads, they haven't let me down yet (XP8's). However, my rotor doesn't seem to like them because I go from stock to XP8's quiet a bit due to tracking the car.

I don't want to go with Power Slot rotors either but hearing that carbotech makes some rotors makes me feel good because they surely test them with carbotech pads.

I would really appreciate it if you could hit me up with the place you order them at. Tx.
 
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