Knock knock sound in the driver wheel well while braking, checked everything.

Hello ppl!

Long time no posts here, my mk4 has been flawless for almost a year.

Until 2 weeks ago.

I started hearing a small TOC in the driver's side front wheel while applying the brakes to a complete stop or even while slowing a little while coasting. Nothing too big but still, this was not normal. I first tought it was a LCA bushing even if they are about 1 year old and I had put the stronger audi type ones. This weekend, while applying the brakes (medium application, for a stop sign for exemple) and under certain circumstences (doesn't happen all the time), the noise came back but it's now a consecutive TOC TOC TOC TOC... while slowing; sometime I will get a last TOC when coming to a complete stop. I endured this until today when I decided to remove the wheel and check what was going on.

I found ... Nothing!

Checked the caliper fixations, sway bar bushing, link-it, shock fixations, ball joint, tie-rod, LCA bushings (both front and rear)

Did I miss something?

Happens in gear or on neutral. Didn't seem to happen on reverse but did not try a lot.

I'm just taking a guess someone already experienced something similar!

thanks a lot !

g.b.

Did you check your pads? I live on a dirt road and it's not unusual to get a tiny stone lodged in the pad area that makes for interesting sounds. Did you check to see if the pads were seated properly? I would completely dissemble that side and reassemble it.

I had the bottom tip of my strut spring break off, about 2" , it just laid in the tray and rattled usually when I went over bumps. Not really a "toc".

Is it rotational? Did you check the wheel bearings. Spin the front tire, or hold the tire at 12 and 6 o'clock , pushing and pulling and see if you get movement.

It could be rocks in the pads or it could be pad separation, which I had not too long ago. The pads were still like new.

Ohh damn! I will disassemble everything and check that out!
The front wheel is pretty hard to spin to see a bearing problem with the axle connected. Usually a beatring going bad would grind doesn't it?

I will check for debris between the pad and disc but I doubt it. It's been more than 500 miles since this started.

It's not a huge sound, if the radio is ON in the car, most of the time you won't notice it.

I will also check for the strut spring... we never know.

My pads are indeed like new, but pad separation could be the cause!

I will double check again. the sway bar bushing seemed to be slack a little bit but it's still complete and doesn't seem to allow any metal to metal contact. Could that be the cause? They lasted less than a year... damn POS

thanks for the help!
g.b.

I was chasing a knocking sound that was annoying and somewhat intermittant. I thought maybe it was the suspension... I replaced everything in the front suspension and the sound was still there. I found a thread here somewhere that was full of good posts, but one the simple ones said to really lube up your door hinges, the lower one in particular. I was running out of things to try, so I thought I would give it a try. Low and behold after a good cleaning and lube with some good waterproof grease, my knock is gone.

Seems too simple, but it worked for me. The sound also seemed to "move" sometimes it sounded like the door, sometimes it sounded like the glovebox.

I had the door hinge creak also when starting, stopping, or going over bumps. Drove me crazy until I lubed the hinges that are directly under the sun roof drains. Don't know if it was the rollers or the torsion bar part of the hinge.

the door hinges... I would have NEVER tought of that! I'll give it a try!

g.b.

Find a GoPro to borrow if you can and strap it under the car. Reproduce the noise and review the footage. That's my go to way to find those gremlin noises.

When I had a similar issue I found it was one of the bolts on the control arm. Couldn't see it budge when I was under the car giving everything the 'ol tug and jiggle but saw it popping on the camera.

how tight are the pads in the holder? it could just be the pads moving around a little bit

How tight are the pads in the caliper? Humm, I'll have to check. There are ''spring tabs'' that are supposed to keep them tight in the caliper but i'll check that out too!

Could a loose axle joint make a Knock noise while braking? I have just tought of that too.

thanks
g.b.

I MAY have found something. I dismantled everything twice... couldn't find anything wrong the first time, then I found the caliper to be slightly loose in it's holder.
However, both sides seems to be similar and only the driver side seems to make noise.

The strange thing is that sometimes it makes the ''Toc toc toc toc toc toc'' noise faster than the rotation speed of the wheel. Like when I'm approaching a complete stop, let's say about 5mph, the toc toc sound is heard. Could the caliper rock back and forth in it's holder during constant braking? I could understand a single ''toc'' (the Caliper hitting the maximum play available) but how could it ''toc toc'' multiple times while i'm not realeasing the brake pedal...?

Here are two small videos showing the play I have.
It was pretty hard to film with 1 hand and show the play with only 1 other!
Is that normal to have play like this? Like previously said, I checked both sides and seems pretty similar.

https://www.dropbox.com/sc/w0tg9iyhfhl31lh/AABRRX1M4qY5AqXrbM1sTvJha

Thansk a lot!
g.b.

anyone?

That amount of movement seems like it's too much. I've done brakes several times and I don't recall the calipers having much if any movement just pushing them by hand.

First thing to check is if the caliper bolts are tight. Pop off the caps that cover the bolts. Check them with a torque wrench, spec is 22 ft-lbs. They take a 7mm Allen.

If the bolts are properly tightened, the other thing to check is the bushings that the caliper bolts ride in. If they're damaged, the caliper could rock back and forth even though the bolts are tight.

The bushings look like this: http://www.ecstuning.com/Audi-B7_A4-Quattro-2.0T/Braking/Caliper/ES2570110/
That the correct part number for the bushings on your car.

Thanks a lot! I may change the bushings again... I already changed them about 1 year ago, but with aftermarket ones. Maybe the softened with time...
The model I bought doesn't accept the plastic caps, they are conical at the end to prevent dirt to enter the area... (I'm probably unclear... but anyway...)

thanksa lot
g.b.

Did you ever determine the cause of this noise??