msylee

Hi all,

Every time I apply brakes, I get this obnoxious vibration in my steering wheel ; just had my front brake pads and rotors replaced and had it re-checked - they seem to be installed properly. It almost feels like ABS/DSC kicking in; but no warning messages.

Any thoughts?

Thanks in advance.

otto6457

Hate to tell you this...but your front rotors are out of spec in regards to run-out. They could have been incorrectly phase matched, or the lug nuts were over tightened or tightened out of sequence. It's also possible the new rotors were out of spec out of the box, but that is unlikely unless you got some really poor quality parts. The other alternative is that they didn't actually replace your rotors and just pad slapped you and sent you down the road.

When they "re-checked" your brakes, did they give you the run-out readings? Did they even test drive the car? It's not like a brake vibration is hard to diagnose. Did they offer an excuse as to why your brakes are vibrating?

It sounds like you got a really poor repair job, either through inexperience or laziness. Maybe both.

Seriously, any shop that can't solve a brake vibration is a shop I would avoid at all costs. This isn't rocket science and is a basic repair procedure taught to first semester auto tech students.

ozusa

Otto makes some fair points...

I suggest the following in addition. Some are phrased as questions for you to ask yourself or your mechanic:

1. How do you know it's not the rear brakes?
2. Look at all 4 disks. It's not essential to remove the wheels. Can you see concentric circles, like the rings of Saturn? With the disks cold so you don't burn yourself, can you feel rings? The deeper they are, the more likely they are causing vibration problems. If you don't know what "deep" means, learn on a car or two that has no issue.
3. I think you are saying the problem started after the brake job? Or do you mean the brake job did not resolve a pre-existing issue?
4. The issue may not be the brakes themselves. You could have wear in the front end components that is exacerbated by braking
5. Look at your tires for strange wear. You may have an alignment issue, but that would tend to make steering wheel vibrations at various times not just when braking.
6. In addition to overtightened wheel lugs, you may perhaps have one that's actually loose. Unlikely, but possible. I mean very loose.

AMGAffalterbach

All of the above are probably more valid points than this but I'll take a shot... depending on the brake setup I would be inclined to think that it could also be uneven transfer of braking material over to the rotors which, most people refer to as a "warped rotor" if you didn't do the proper break-in on the new pads/rotors.

StopTech has an excellent write-up on this, and let me preface this by saying that Otto knows way more than me on diagnosing problems, but it's just a thought. People think that rotors warp but that's largely a misnomer, whereas the more likely cause of vibration when you step on the brakes isn't a warped rotor but an uneven transfer of new braking material to the rotor that builds on up the surface - causing a variation in thickness that most people attribute to a warped part. If you or the technician didn't "bed in your brakes" then this could very well happen.

msylee

thanks guys!

it is more noticable when braking from 30-40mph - i can not feel it if i am braking from lower/higher speeds than that....

front brake pads and rotors were replaced because mainly they were worn; however i was getting vibration also. right after the replacement, the vibration did go away; but came back after 2-3weeks.

i had the shop re-check on the brake issue; because they were replacing my tires... i am taking it back on Monday to have them focus on this nasty vibration - any suggestions that i should make when i drop off? don't want to get screwed because im a woman lol :-P

AMGAffalterbach

I just realized that, and also welcome to the forum! I would just tell them to check the aforementioned if possible, but I would try to find a GOOD independent shop that won't screw you. That's the only way to ensure not getting screwed, or just straight up refuse to pay more for their bad job simple as that. The way I do it is I take my car in for regular maintenance at the dealer which you get several benefits (including free roadside assistance from) and then my other work such as repairs and brakes at a Mercedes-only independent shop - it works out well. Be tough with them and since you know what you're talking about, just be assertive