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Source of slight front judder under braking?

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Hi again all,

My Boss is at 2,500 miles now, with a significant portion of that on the track. I'm on to my second set of brake pads (OEM) and tires (definitely not OEM). The car was stored over the winter (heated garage, regular tire rotation, etc.) just after the new pads and tires were installed, and I got it back out on the road last month. No track time yet this year, unfortunately. I had one track day last fall with the new tires and pads before storing the car.

Driving on the street this year I've noticed a very slight judder under braking (normal street driving). It feels like the brakes are just a bit "off" somehow . . .I get a small vibration in the steering wheel rolling up to stops. It's hard to describe, but the brake pedal doesn't quite feel as linear as last year - almost soft with not as much grab as I recall. Of course, it's been months since I drove the car, and driving on the street with cold brakes is a different experience compared with being on the track with warm brakes.

No sounds or squeals under braking.

Does anyone have any suggestions on what this could be, or how to troubleshoot it? Perhaps it was always like this?

Thanks!
 

Senderofan

Having more fun than should be allowed..in my Boss
Not sure if you've done this already...but you could probably stand to change your brake fluid, if you've done a fair amount of track time.....bleeding them when you change the fluid. This would rule out air in your system.

Also, have you been running DOT 4 fluid??? Or the factory DOT 3?

Just something that comes to mind at first glance of your description.

Wayne
 
Try rebedding your pads. You've either got uneven pad deposits (most likely), or (unlikely) you have warped rotors. However, I doubt you'd warp them using stock pads.

It's always best to start a season after storage with a fresh high temp fluid for the track. That however won't cause the judder, but could cause a soft pedal.
 

Grant 302

basic and well known psychic
I'd suspect alignment first if you feel it in the wheel. But I can't say I have experience with judder. Do you have visible signs on your rotors?
 
Hi all - I'll start with replacing the brake fluid, and then go from there. Stay tuned for an update.

Thanks for your suggestions. Much more insightful than, say, the dealer, who, to be fair, has their hands full with more run-of-the-mill problems.
 
A fluid flush should help the pedal feel, but your judder is almost certainly pad deposits. You may have glazed the pads too, depending on how hard you're driving on them. Even if you've installed new pads, the problem will persist. The glazed material is baked onto the rotors. If you're going to stick with stock pads, get your rotors turned and rebed your brakes. If you're going to use a race pad, then it may be able to "clean" off the pad deposits if you drive around with them cold (i.e. don't get them hot and bed them in at first). Most brands will be able to do this, but don't try it with carbotechs. They have a different composition and don't have the same abrasive nature when cold like other metallic based pads. You'll ruin the pads
 

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