If this is in the wrong forum, sorry. I couldn't find a "tires, wheels, brakes" forum like there used to be.

When I brake, regardless of road conditions, the pedal and steering wheel vibrate somewhat, as though a disc is warped or distorted in some way. Is there a visual inspection anyone knows of that might give a clue as to which disc(s) is/are a problem?

The other thing about the symptom is that the harder the braking, the rougher it feels. There is no pulling to either side, and the car stops all right (although I haven't scientifically tested it. No squeaks or squeels.

FWIW, I have EBC slotted and "dimpled" discs frt and rr, Green Stuff pads, and the TMS metal caliper bushings. >20,000 miles on the set.

Thoughts or ideas?

Thanks.

 

Hey mark,
When i drove your mini the other day i did noticed you brakes
were pretty rough. To me it did pull to the left under normal to hard braking.
Something did'nt feel right to me as i metioned it to you.
It should never pull to one side under hard braking... dangerous.

If it was my mini i would have a shop pull them off and inspect them.
Get them suckers looked at asap.
Todd

 

This may read as odd, but any time that I have used a performance street pad, pad material has transfered to the rotor after about 5-8K miles - fairly hard driving.

I can only guess that the pads in this family, and I've used many makes, transfer material when very hot, but do not posses the necessary abrasive quality to clean the rotors.

The same condition occured with my 12.4" Willwood kit; I used the bp10 pads and the slotted rotors pulsated after about 10k miles. I ordered new non-slotted rotors with Poly B pads for race day only. But I did used these pads on the previous slotted rotors for one day and they cleaned the rotrs up very nicely. The Poly b pads are not for every day, just track; they are quite noisy and will wear rotors very quickly when cold - they need heat.

Personally, I would stick with stock pads unless you are going to the track. Then just switch out the pads at the track, no big deal. This takes about 5min per side with the Willwoods...stockers about 15min per side.

 

Okay. Thanks for the input. "Pulsating" is sort of a good term to describe the feeling I'm getting. As far as pulling to the left, the ABS seems to me to be not as smooth - I'm not certain that's exactly the right term -- as I think it should be, but I have not felt any outright "pull." It is almost as thought the ABS system is getting inconsistent or poor "signals" from the system.

I'll take it in. Since I'm going inot Fireballed on Monday, I think I'll ask them to have a look. Otherwise, I'm going to give your guy in San Pedro a try, Todd.

Thanks.

 

Could be an alignment issue, odd tire wear, or uneven material transfer; a high spot on one rotor may be a low on the other, reality in fact. This may signal a bit of threshold braking on one side and not the other.

Here's an option, purchase a set of race pads, but a type that is kind to rotors, but still abrasive. Use these to clean your rotors every now and again.

Also, remember to evenly torque your wheels. I went thru one exhaustive debate here about a year ago about rotor warping - it does indeed exist but most of the time material transfer is blamed for warping. If the lug nuts are not even ly torqued, or are over-torqued, the rotor may indeed warp if it brought up to a certain heat threshold. 85 ft lbs is fine.

 

My experience matches meb's. Hawk HPS pads for me, and if I use them for daily driving, they develop pad deposits and cause pulsating under braking. Get them nice and hot, and things even out pretty well for a while. Throw a set of abrasive pads in for a bit and things quiet down completely.

 

Thanks, red_line, meb and snid.

As an experiment today on the way home from work I really stomped hard every place I possibly could all the way -- going from 40 to 70 down to 20 or stopped ASAP. Not panic stops, but REALLY hard braking. I probably go to do that 2-3 dozen times (So Cal freeways offer many stiop and go opportunities).

It seems to have helped as by the time I got home they were much smoother. I think the material deposit phenomenon must have been what was going on. I have been unintentionally babying them a lot with very few opportunities to drive hard lately --- just my daily commute.

I'll see if they still feel better tomorrow, but so far, I would have to say that the deposits seem to have been the problem.

Motor on!!