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Brake judder... again!
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Old 29 Dec 2011, 05:25 PM   #1 (permalink)
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Brake judder... again!

I apologize in advance for this long and boring story, but as some of it may help determine the problem I thought I had better start from the beginningÖ

I fitted new discs and pads front and rear (Red Dot), months later I took the car to the Nurburgring, after 3 corners there was a huge amount of juddering when braking (felt through the pedal, steering wheel and the entire car really). By the end of the lap even fairly gentle breaking would feel like driving down a cobbled street at ridiculous speed.

I replaced the front discs and pads again but this time with EBC (Yellowstuff pads & grooved discs). In doing this I found a seized piston in each caliper (Subaru 4 pots), so cleaned the one piston up and replaced the other one which looked quite bad with a stainless steel piston. After bedding in the new discs & pads the problem appeared to be cured...

Until my next ring visit about a year later, after a few laps there was some juddering again, no where near as violent as before, about 20% as bad as before, also it could not be felt through the steering wheel this time.

On my return I replaced the rear discs & pads with EBC, all then seemed well.

Recently though, some judder has developed when braking, again felt through the pedal and steering wheel (suggesting front brakes again?). Itís nothing like as bad as the first time, but itís not good!

Iíve tried pushing the pistons in on one of the front calipers (got to check the other side at the weekend), one of them seemed harder to push in then the others, but certainly didnít seem to be seized solid.

I donít want to go ahead and change the discs and pads again as I think there may be some issue somewhere that is causing the discs to last such a short time (fronts have been on for just 10,000 miles).

If anyone has any ideas they would be greatly appreciated, Iím pulling whatís left of my hair out now!
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Old 29 Dec 2011, 06:07 PM   #2 (permalink)
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Re: Brake judder... again!

Save up for brembos and convert if you are doing heavy work like the ring.
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Old 30 Dec 2011, 04:42 PM   #3 (permalink)
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Re: Brake judder... again!

sounds like you are cooking the discs at the ring and warping them.
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Old 31 Dec 2011, 01:28 PM   #4 (permalink)
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Re: Brake judder... again!

Are the discs fitted correctly in the right rotation? if the grooved discs are going against the rotation you will get vibrations through the steering wheel were the discs stamped LH RH at all? only fitted brembo discs and pads to a car recently drilled and grooved and it shows you in a diagram the way the wheel rotation must be when they fitted, could you take a pic with the discs on the car of course and we could tell ya? the groove should be starting from the inside of the disc working out to the end tip of the disc with the wheel rotation going clockwise and thats the drivers side on a right-hand drive car if you know what I mean, did you only notice it at the track or was it the case that the car was driven handy before the track and you would not have noticed a problem until car driven at high speed?
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Old 02 Jan 2012, 04:18 PM   #5 (permalink)
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Re: Brake judder... again!

Jd: That was my first thought, just canít believe the Red Dot set up only lasted 3 corners!. Iíve used EBC before on my 170bhp Civic, which did 3 ring trips with no issues, but then I think itís fair to say the Impreza is more demanding of its brakes.
<P>
Shambles: Any idea if the gold Brembo calipers as fitted to later Imprezas fit the classics (2000 V reg)? Iíve heard that they do, but donít know if my wheels would clear them as thereís only millimeters of clearance between the wheel and original caliper.
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stiimpreza1984: Iím 99% sure the discs are the right way round, if I remember rightly they came in boxes marked left and right. I have attached some pictures which will hopefully work! (driverís side is the picture with the wheel on the car).
<P>
The car is regularly driven quickly, but I'm not big on hammering the brakes and have a lot of mechanical sympathy, so itís certainly possible the brakes have never reached the temperatures on the road that they did at the ring.
<P>
Checked the caliper on the other side, a couple of the pistons took a bit more force then the others to push back in, but they have all moved back. Should the pistons all move very easily? I did find that one of the pins that holds the pads in place was a bit bent, which I havenít noticed beforeÖ
<P>
Cheers guys.
Attached Images
File Type: jpg driver.jpg (139.1 KB, 16 views)
File Type: jpg passenger.jpg (115.8 KB, 19 views)
File Type: jpg pins.jpg (89.7 KB, 14 views)
File Type: jpg clearance.jpg (44.1 KB, 13 views)
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Old 02 Jan 2012, 09:53 PM   #6 (permalink)
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Re: Brake judder... again!

Ya they fittd perfect u know the way the groove is with the rotation strange as JD said sounds to be the problem a friend of mine in an integra type r had his front caliper seize but he had no vibrations through the wheel he bought a rebuilt kit from honda and we cleand out the piston was all rusty cleand it up greasd it up and new seals and sortd now maybe it needs a full rebuild the 2 front calipers but id agree with JD
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Old 03 Jan 2012, 01:02 PM   #7 (permalink)
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Re: Brake judder... again!

speak to Ian Godney at Godspeed Brakes - Godspeed Brakes regarding brake upgrade packages.
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Old 14 Mar 2013, 05:41 PM   #8 (permalink)
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Re: Brake judder... again!

Is it easy to tell if youve cooked new discs as I went through new pads after 1/2 day track racing with new grooved discs on?
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