Mr. Z

[Yeah, I know this has likely been covered in depth elsewhere, but my mind is unfortunately elsewhere, so please bear with me]

Despite the fact that the indy shop thinks a bad shock is causing the clunking sound on the driver's front wheel, I worry that the rotor is warped. When I drive VERY slowly and it is VERY quiet outside, I can hear a faint, speed-dependent "shick-shick-shick" sound -- once per wheel rotation. The braking clunk has gotten worse. If I apply light brakes at 15 mph or less, they sometimes feel like they're "catching" and locking. Mild braking from 30mph gives me a definite sound and vibration. Hard braking is just fine.

So... Shop wants $140 for labor to replace the rotors & said they can get replacement rotors for $88 (std.) or $100 (drilled). Catch with drilled is that they'd want to do all 4 at once instead of just the front two. They also suggested I check with you guys to see if there is a better deal/option. If OEM is the best price/performance, then I don't need fancy. My 5ksq had vented, but non-drilled discs and I liked 'em. The pads are currently at 80%, but I don't know the make/model. Not likely top shelf. I also have a brand new set of Beck-Arnley semi-metallics that I could have them put on (at no extra charge).

Thoughts? Suggestions?

Pete K (vegasguy)

You could very easily have both problems.

PaulW

What kind of pads do you have?

Mr. Z

Don't know what on there now (from prev. owner), but replacements would be aftermarket semi-metal

MP4.2+6.0

The ticking each revolution could be from a lot of things--rotor interference/out of true, something loose inside the tire itself, problem with a brake heat shield, something stuck in the tire tread, parking brake hanging up rear wheel a bit, etc. Sometimes I find if you drive next to a concrete wall with your window down, you can hear it a bit better.

Clunking could be the shock as suspected. It could also be the upper or lower mounting point, almost any part of the suspension that is worn, a loose clamp on the front anti sway bar or the connecting link to the suspension it bolts to, etc. It could also be a bad motor or tranny mount where the backing off the torque comes back through the driveline as play. Could also be loose bolts where the caliper is bolted to the hub. I would check those bolts first, as well as look for worn suspension parts.

BrianC72gt

My latest noise from the front end was a combination clunking and groaning on tight turns. It was the half shafts. It also gave clunking on accelleration and decelleration. Replacetd them and the front end is now tighter than a .... never mind. All the noises are gone. Are the spring clips still on the outside of the calipers? That could cause the outer pad to dance around a little in slack.

Regards,

Brian C.

Mr. Z

Thanks for input, BUT... what are best front rotor options if I have to replace??

MP4.2+6.0

Drilled are for show, not for performance bottom line. If they are factory cast with the holes that's a different story. Holes drilled into a raw disk, which is what most anything out there aftermarket will be, will tend to lead to stress cracks around the holes over time. If you want any enhancement, slotted is considered the better way to go--it allows outgassing and scrubbing of the pad like drilled, but doesn't have the same tendency to promote stress cracks like drilled.

For everyday driving though, what's on the car is plenty fine. You are driving a car on 65MPH highways that has a brake set installed to drive up to 155MPH on autobahns. I'm an A6 4.2 guy with similar size brakes and big factory tires; the limiting stopping power is still the tires not the brakes, and these cars will do throw-your-eyeballs-out-of-sockets stops if you ever stomp on the pedal on a deserted road in a 60 or 70 or 80 to 0 full on stop, and they'll do 3 or 4 in a right in a row before you start to get some smell and smoke.

Having said all that, my next set of front rotors will be a set of DBA slotted rotors--hard to find improved rotors made by Disk Brakes Australia (hence "DBA"). Ate also makes a slotted type of rotor for many cars--it's a kind of odd rounded star pattern I don't think really passes the performance looks test, but it's subjective. Many other slotteds are again just cut into a stock blank later. Common stock/OEM type rotors include Brembo, Ate, Zimmerman and a few others. Stock is plenty fine though for any regular street driving.