New brakes and now a wobble?

[contrail_25]

Background:

2001 Subaru Outback sedan, 2.5L, auto, 152K

I don't have much mechanical experience when it comes to cars outside changing oil, ect. I'm very proactive on major preventative maintenance though, I just have mechanics do it.

Issue:

I had new brakes/rotors installed back in October, just developed a 'wobble' in the steering when I brake from high speeds. I can also feel a small wobble in the steering while driving, but you can't see it in the video. No feedback in the brake pedal. See the video linked below.

YouTube - brake test

YouTube - brake test

Shop used OEM parts. Currently have just under 5k miles on them. The car is my daily driver, to-from work is about 15 miles a day, partly on the autobahn (80mph). New tires, with about 6k on them.

The front drivers side also makes a high-pitched, low volume metal-on-metal sound that is cyclic as if the rotors are warped. Same wheel also occasionally makes a grinding sound at low speeds (less than 10 mph) when turning to the right.

I'm taking the car in, but have to wait until the 10th since the shop is busy. I have access to a full hobby shop on base, but am slightly leery about working on brakes myself.

[Petersubaru]

Originally Posted by contrail_25

Background:

2001 Subaru Outback sedan, 2.5L, auto, 152K

I don't have much mechanical experience when it comes to cars outside changing oil, ect. I'm very proactive on major preventative maintenance though, I just have mechanics do it.

Issue:

I had new brakes/rotors installed back in October, just developed a 'wobble' in the steering when I brake from high speeds. I can also feel a small wobble in the steering while driving, but you can't see it in the video. No feedback in the brake pedal. See the video linked below.

YouTube - brake test

Shop used OEM parts. Currently have just under 5k miles on them. The car is my daily driver, to-from work is about 15 miles a day, partly on the autobahn (80mph). New tires, with about 6k on them.

The front drivers side also makes a high-pitched, low volume metal-on-metal sound that is cyclic as if the rotors are warped. Same wheel also occasionally makes a grinding sound at low speeds (less than 10 mph) when turning to the right.

I'm taking the car in, but have to wait until the 10th since the shop is busy. I have access to a full hobby shop on base, but am slightly leery about working on brakes myself.

..with no feed-back in the brake pedal..I then doubt if the rotors are warped..I would recommend that both front wheels be "balanced" (I don't mean an alignment) and have your brakes inspected again, especially the sliding pins..hopefully they are not hydro-locked..if so, the shop needs to use the proper grease for lubricating the pins..

[mrk610]

I would take it back to the place you got the brake work done . That is a warped rotor to me. I would also make sure when they did the job that the seated and did the initial break in on the new pads and rotors. There are steps that need to be taken to properly break in the new brakes . Looks to me they didnt and just sent you on ur way and the first time you stopped you heated the brakes up they warped.

[neutron]

Originally Posted by mrk610

I would take it back to the place you got the brake work done

+1 on this, unless you now don't trust the shop... sometimes taking a car back can be more of a hassle than fixing it yourself!

Get the runout of all four rotors checked. If runout is within spec (0.004" max) then there's probably a sticky spot on a rotor that's causing cyclical uneven braking (shudder).

You won't always get feedback in the pedal from excessive rotor runout.

A lot of people use the term "warped rotor," but usually the runout is caused by something else, like dirt between the rotor and its mounting flange.

[plain OM]

Were any wheels removed and reinstalled since the brake job in October? Wondering if a wheel wasn't mounted properly on the hub. Also, have the lug nuts been checked since that work to make sure they are still all torqued properly.

[subiesailor]

My 01 would do that same exact wobble after sitting for a long time on soft tires. I would take them up to around 35-36lbs and after a couple of days the wobble would go away. Did the same wobble when a tire got a little loose after a bearing replacement.

[contrail_25]

So finally had my shop appointment today:

Front rotors are "badly" warped. Rear Rotors are "marginal"
Both sets of pads are %50 worn.

I talked with the mechanics for a bit, they were also surprised at the extreme rate of wear on the brakes (4 months, less than 5,500 miles).

I don't take the car in the mountains, no real hills, no long trips. The daily use is mainly city roads, punctuated by 2 miles on the autobahn. Even then I only get up to around 75-80, and brake to about 55-60 for the exit using it's S-turn shape to slow down further. And this isn't every day. Sometimes it's only 1-2 times a week and the car sits. So the use is very low. My technique hasn't changed, the last set of brakes was fine for over a year here (and those rotors had been turned once previously) and had been good for over a year back in the states prior.

Same parts as last time, forget the name though. It's just very dumbfounding. The only good part of this trip to the shop was finding out that the baking plate was rubbing and making most of the noise I heard.

The other find was that my FDS inner tie rod was damaged, as well the sway bar end links (loose). Interesting.

Total for the parts was just over $300 plus whatever labor will be done.

[davekra]

The work has already been done but a wobble can sometimes be uneven deposition of brake pad material on the rotor.
I can't find the link I want right now, but if there is a wobble sometimes bedding the brakes can solve it.
It involves going from 50mph, hard brake to 10mph, then back up to 50mph. Repeat 10 times, never stopping completely, then drive at like 30mph to cool the brakes.
I did this to my VW after replacing the pads and it developed a wobble if you applied the brakes lightly at freeway speeds. It solved the problem and actually stopped better after.

Found the link
http://www.stoptech.com/tech_info/wp_bedintheory.shtml

[rwachtell]

Originally Posted by contrail_25

Background:

2001 Subaru Outback sedan, 2.5L, auto, 152K

I don't have much mechanical experience when it comes to cars outside changing oil, ect. I'm very proactive on major preventative maintenance though, I just have mechanics do it.

Issue:

I had new brakes/rotors installed back in October, just developed a 'wobble' in the steering when I brake from high speeds. I can also feel a small wobble in the steering while driving, but you can't see it in the video. No feedback in the brake pedal. See the video linked below.

YouTube - brake test

Shop used OEM parts. Currently have just under 5k miles on them. The car is my daily driver, to-from work is about 15 miles a day, partly on the autobahn (80mph). New tires, with about 6k on them.

The front drivers side also makes a high-pitched, low volume metal-on-metal sound that is cyclic as if the rotors are warped. Same wheel also occasionally makes a grinding sound at low speeds (less than 10 mph) when turning to the right.
I'm taking the car in, but have to wait until the 10th since the shop is busy. I have access to a full hobby shop on base, but am slightly leery about working on brakes myself.

I'd bet that grinding noise when turning at low speeds to the right is coming from the back plate rubbing againts the rotor at the location behind the tie rod joint.