Wife's A4 issues....

[jonohio]

Before you say "oh, god not another vibration post" here me out. I have owned several german cars in the past and maintained them all myself. I've generally been able to tackle everything without issue, but this one has me frustrated. I've tried to be methodical in troubleshooting this.

Here we go:
1. Wife's '07 A4 quattro 2.0T sedan with 89k miles.

2. In the last 3 weeks there has been a vibration present when braking. Either lightly touching the pedal all the way through full application from what sounds like the front right wheel only. The vibration is not present in the pedal but in the steering.

3. At first i lifted the car up and tugged on the wheel at 1/3 & 12/6 and was sure I felt a little play on the inner tie-rod. I took it to the dealer and they said "you need all new pads and rotors" and it's not the tie rods. I don't buy it, but.....

4. I went home and took off the front right ate rotor (ate rotors and akebono pads were replaced 35k ago) and replaced the rotor with a new Freemax. Vibration was still there exactly as before the rotor change.

5. Wondering if the pads were part of the issue i swapped the front left pads with the font right pads and experienced the same vibration.

6. I did notice the right hand caliper boots seemed looser than the other side, so I installed new boots and guide pins in the caliper. Vibration is still present, exactly as before.


I drove around with the car for about 30 minutes today and payed very close attention to what I was experiencing. Here's what I have confirmed.

- The vibration is present at all speeds when braking, light touch on the pedal or heavy pressure. Braking vibration frequency at 60 mph feels similar to bad wheel bearings (in other cars when turning). About 15 pulses per second id guess.

- The vibration/pulsing slows down in frequency and intensity as speed slows and when dropping below 10mph i feel a grind or hesitation (like an abs pulse in bad weather).

I'm not terribly familiar with the suspension components in the car but i've heard that worn suspension components can contribute to this vibration. Any thoughts?

Part of me wonders if I have an ABS or wheel sensor issue even though there are no lights on.

Any thoughts are welcomed.

- Jonathon

[AKO]

Have you had your tires rotated recently? When was the last time they were balanced?

[kegobeer]

Check the caliper assembly. New rotors and pads won't fix anything if the caliper is cracked or loose. Something to check anyway.

[FraggyA4]

1. Did you properly seat your pads?
2. Have you ever heard of Brake judder?
Read this it's probably your problem. http://www.powerbrake.co.za/download..._01_judder.pdf

[jonohio]

New tires were installed and road force balanced in June of this year.

Have you had your tires rotated recently? When was the last time they were balanced?

[jonohio]

Yes, the pads were properly bedded.

I have never heard of brake judder, but wouldn't that go away when I replaced the rotor? I take the air wire wheel to the hub every time and coat the hub with anti-sieze as well.

Based on this article, perhaps I should re-install the rotors and put new pads in too...thoughts?

1. Did you properly seat your pads?
2. Have you ever heard of Brake judder?
Read this it's probably your problem. http://www.powerbrake.co.za/download..._01_judder.pdf

[FraggyA4]

Yes, the pads were properly bedded.

I have never heard of brake judder, but wouldn't that go away when I replaced the rotor? I take the air wire wheel to the hub every time and coat the hub with anti-sieze as well.

Based on this article, perhaps I should re-install the rotors and put new pads in too...thoughts?

If you had it on the old rotor then your pads wore accordingly to that. So on the no rotors it would cause weird braking. Also you can get deposits on the pads after braking on bad rotor. So typically you would want to start with a clean slate.

[jonohio]

So do you think I'm I safe to assume the suspension components are a zero factor?

If you had it on the old rotor then your pads wore accordingly to that. So on the no rotors it would cause weird braking. Also you can get deposits on the pads after braking on bad rotor. So typically you would want to start with a clean slate.

[FraggyA4]

So do you think I'm I safe to assume the suspension components are a zero factor?

The biggest issue our cars have with suspension is usually the control arm, and that makes a clunk that will drive you nuts.

[JayDog747]

The car has 90k on it. More than likely it needs a front end refresh. When you raise the front end, look at the upper control arm bushings. If you should see a nice split in the rubber bushing, plan on replacing those soon. Remove the tie rod from the steering knuckle. If the inner tie rod cannot support the weight of the outer tie rod, consider replacing.

From the way you've described it, I would look at the tie rods. Just outta curiosity, do you have to make corrections in the steering to keep the car tracking straight?

[kegobeer]

The biggest issue our cars have with suspension is usually the control arm, and that makes a clunk that will drive you nuts.

Our cars have clunks that a front end refresh won't fix, either. I put all new control arms, tie rods, you name it, all in the hopes of ridding myself of clunks, to no avail. Don't forget the stupid loose calipers that wear out around the caliper guide pins - that causes clunks, too.

[80sGuy]

According to your explanations, it sounded like the culprit lies within the brake system, and correct me if I'm wrong but this is 'brake pulsation' transferring in to your steering wheel. I think your issue should be resolved with ORIGINAL OEM AUDI BRAKE PADS and ROTORS. Uneven or the slightest warped discs will completely throw off your new pads and generates unwanted pulse/vibrations.

For the meantime, you can try doing this but I doubt it will hold...
http://www.instructables.com/id/Get-...-when-braking/

[FraggyA4]

The car has 90k on it. More than likely it needs a front end refresh. When you raise the front end, look at the upper control arm bushings. If you should see a nice split in the rubber bushing, plan on replacing those soon. Remove the tie rod from the steering knuckle. If the inner tie rod cannot support the weight of the outer tie rod, consider replacing.

From the way you've described it, I would look at the tie rods. Just outta curiosity, do you have to make corrections in the steering to keep the car tracking straight?

I'm at 130k and my front end is fine, it's not uncommon to go 150k on front end except for the case of the control arms and shocks & struts.