Hey guys,
This may be a silly newbie question, but I've noticed that my TL-S stutters a bit when braking hard. It feels like the brakes aren't getting a good grip when I brake hard, and it feels as though the vehicle instead stutters and struggles to come to a complete stop. I have new-ish stoptech pads on, however I still have the original rotors on them (80K miles). Is this issue directly related to the rotors?

If it is I'm thinking about getting these?
http://www.heeltoeauto.com/stoptech-...roductid=66105

Thanks guys. Any feedback would be greatly appreciated.

 

yep, rotors. most likely pad deposits on them, but since you have 80k miles on them, I would highly suggest getting new ones. no point in trying to resurface them or sanding them down and rebedding them with 80k miles on a 7 year old rotor
If you just want to get rid of the vibration, any good brand new rotor is fine, although stoptech is definitely a pretty good rotor to go with.

 

are you sure it's not the abs system? do you feel vibration and pulsation through the brake pedal?

 

If its a grinding type of noise when youre braking hard on snow its your abs but if your wheel is shaking while braking its your rotors. You said you just slapped pads on the old rotors without cutting them or better yet swapping them out. The old rotors have grooves in them from the pads you replaced so the new pads arent doing you any good since theyre not having full contact with your rotor. Hope this helps

 

Its ABS activation

 

Sure sounds like ABS…

OP - When you brake just moderately hard (not full on panic) do you get the same "stuttering" you are complaining about?

When you brake really hard, enough to cause the tires to lose traction, the ABS system will pulse the brakes for you and it will feel much like what you are describing.

If you are not getting these symptoms unless you are braking really hard, then what you are feeling is completely normal. The ABS system allows you to be able to continue to steer and control the car in a panic braking situation.

 

Thanks guys for the replies.

It's not a grinding noise over snow / slippery surfaces (It doesn't snow where I am, and this isn't happening in the rain, just normal conditions). I am considering getting new rotors regardless. However, they're pretty expensive...it it not advisable to just replace the front rotors?

I'm not sure if I feel it THROUGH the brake pedal, since when it happens I simply freak out haha. I don't think there's clear "feedback" through the brake pedal though. The vehicle also definitely feels like the brakes are NOT slowing it down as much as they should. It stutters as though it's trying to break but cannot. There is also a VERY AUDIBLE vibration/stutter sound when this happens.

Perhaps

I've gotten this stuttering intermittently when braking - it seems to appear most frequently during moderate to hard braking to a stop.
When the ABS kicks in, should it still produce an audible vibration/stuttering sound? I understand what you mean when you state that the ABS allows me to continue steering, but it seems like the braking capacity is being hindered, which leads me to think that it's not just the ABS but bad/old rotors...

 

you can just replace the front rotors and leave the rears alone if there is nothing wrong. You can generally replace rotors on the same "axle" in pairs.

80k is a long time to go on the OEM TL-S rotors (but that is pretty dependent on how you drive). You also dont have to buy OEM rotors which when i last bought them were around $250.

 

From my experience, there's still many miles left on 80K rotors. I replaced my rotors at 111.5 and they were still well within spec (23.5mm).

OP, it would have been best if the rotors had been sanded before adding the new pads. It's not too late to do that. I'd give that a try before forking over $$$ for new rotors...

 

Are your CV axles leaking and slinging grease around? That can cause the ABS to kick in more often than it should.

 

i don't believe there's grease but i also don't think the rotors were ever sanded when the pads were replaced. unfortunately this is something i didn't trust myself to do so i had a mechanic do it - maybe i'll have him check it out and see if he'd be willing to sand it down.

i think the combination of information from some of you guys suggests that after I inquire my mechanic about the possibility of it being purely ABS, sanding might be the best first fix, followed by replacement of the front 2 rotors (likely with stoptech).

Thanks all you guys for the helpful tips and advice - I'll update when I get to the bottom of this

 

And I forgot to add: after sanding, you should re-bed the pads IAW Stoptech recommendations/procedures...