Single tapping sound on initial braking. Likely culprit?

[Kiwi79]

Hi PHers,

Wondering if anyone has had similar before. I noticed today that when I start to brake there is a single tap, a bit like two clogs being hit together. If I continue to brake it's gone. Let off the brake and press again "tap". It does this at low speed going on and off the brakes. Tap, tap tap arghhh.

Is it most likely to be the pad moving and colliding with the caliper? If so how have people solved this?

Car is an 2008 S3 and brakes and discs were done approx 1000 miles ago by a decent outfit with OEM parts.

Edited by Kiwi79 on Thursday 27th October 20:54

[Toltec]

Could be a worn suspension bush.

[rigga]

Loose caliper bolt

[Cold]

Probably just the pad moving in its mount (in the direction of the disc's rotation). Are they genuine or quality aftermarket pads because sometimes the dimensions of inexpensive replacements aren't always accurate. Failing that, sometimes the anti-rattle or anti-squeal devices can become less effective over time.

[Alias218]

Cold said:

Probably just the pad moving in its mount (in the direction of the disc's rotation). Are they genuine or quality aftermarket pads because sometimes the dimensions of inexpensive replacements aren't always accurate. Failing that, sometimes the anti-rattle or anti-squeal devices can become less effective over time.

I was going to say just this. When braking in reverse I get a little 'clack' as one of the pads shifts upwards slightly (don't hear it going forwards possibly due to higher speed and road noise). I use OE spec Brembo hardware bought from ECP, so hopefully not knock off gear.

[TVR1]

Kiwi79 said:

Hi PHers,

Wondering if anyone has had similar before. I noticed today that when I start to brake there is a single tap, a bit like two clogs being hit together. If I continue to brake it's gone. Let off the brake and press again "tap". It does this at low speed going on and off the brakes. Tap, tap tap arghhh.

Is it most likely to be the pad moving and colliding with the caliper? If so how have people solved this?

Car is an 2008 S3 and brakes and discs were done approx 1000 miles ago by a decent outfit with OEM parts.

Edited by Kiwi79 on Thursday 27th October 20:54

I note the wheels have been off recently. Perhaps also a good idea to check wheel nuts and re-torque. That 'tap' could also be the wheel slapping against the hub as the bolts loosen. Ask me how I know.

[Conscript]

Cold said:

Probably just the pad moving in its mount (in the direction of the disc's rotation). Are they genuine or quality aftermarket pads because sometimes the dimensions of inexpensive replacements aren't always accurate. Failing that, sometimes the anti-rattle or anti-squeal devices can become less effective over time.

I'd vote this. Had exactly the same symptoms on a car before, turned out to be the pads moving back and forth ever so slightly within the caliper with the movement of the disc. Solved it by buying new retaining clips.

[Kiwi79]

Conscript said:

I'd vote this. Had exactly the same symptoms on a car before, turned out to be the pads moving back and forth ever so slightly within the caliper with the movement of the disc. Solved it by buying new retaining clips.

Sounds plausable and would fit the symptoms.

Fitting the retainer clips: is this a 5 minute home job or is it actually refitting the pads as well?

[Kiwi79]

TVR1 said:

I note the wheels have been off recently. Perhaps also a good idea to check wheel nuts and re-torque. That 'tap' could also be the wheel slapping against the hub as the bolts loosen. Ask me how I know.

Good shout. I think I will check tightness. I'm hoping it isn't this as the garage have a very good rep so I won't be impressed if it is!

PS. We need to hear how you know!

[battered]

Kiwi79 said:

Sounds plausable and would fit the symptoms.

Fitting the retainer clips: is this a 5 minute home job or is it actually refitting the pads as well?

It's a 5 minute job including pulling the pads out. It's common. I had ah antirattle shim or spring go rusty and fall out. It doesn't take long to happen sometimes. Fortunately it's an easy fix.

[TVR1]

Kiwi79 said:

Good shout. I think I will check tightness. I'm hoping it isn't this as the garage have a very good rep so I won't be impressed if it is!

PS. We need to hear how you know!

As if- as they say-by magic...... M1, early morning, doing the speed limit.

[akirk]

Kiwi79 said:

when I start to brake there is a single tap, a bit like two clogs being hit together

dutchman in the boot?
this is PH - powerfully built directors all have bodies in the boot - maybe this one wasn't 'done' correctly

[Conscript]

Kiwi79 said:

Conscript said:

I'd vote this. Had exactly the same symptoms on a car before, turned out to be the pads moving back and forth ever so slightly within the caliper with the movement of the disc. Solved it by buying new retaining clips.

Sounds plausable and would fit the symptoms.

Fitting the retainer clips: is this a 5 minute home job or is it actually refitting the pads as well?

It requires taking the pads out, but that is an easy task. The retainer clips are basically the aluminium "shims" that sit in the recess of the caliper, and then the lugs on each end of the pads sit within them - it allows a smooth surface for the pad to slide back and forth on. But if they are loose, they allow some lateral movement of the pads, which makes the tapping noise you are hearing when you initially press the brake pedal.

See this link...about half way down the page, there's a section entitled "Replace the retaining clips" which has detailed photos which should make it clear

http://www.edmunds.com/how-to/how-to-change-your-b...

[Rawwr]

Are you driving in clogs?

[battered]

TVR1 said:

As if- as they say-by magic...... M1, early morning, doing the speed limit.

Ouch. Nearside wheel, of course. I had one go many years ago, fortunately I'd heard it rattling some while before and slowed to a walking pace on a country road.

[james_gt3rs]

Track/race pads can make this noise. This is because they are slightly smaller than OEM pads to allow for thermal expansion. So when they are cold they rattle around a bit.

[Ozzie Osmond]

TVR1 said:

As if- as they say-by magic...... M1, early morning, doing the speed limit.

A wheel came off at motorway speed and propped itself neatly against the Armco? :sctratchchin:

Some years ago on the way to Le Mans we passed a TVR 350i on the hard shoulder with its left rear wheel missing and driver still in the car. Half a mile further down the autoroute we passed his missing wheel, still rolling towards La Sarthe...

[anonymous-user]

TVR1 said:

Kiwi79 said:

Good shout. I think I will check tightness. I'm hoping it isn't this as the garage have a very good rep so I won't be impressed if it is!

PS. We need to hear how you know!

As if- as they say-by magic...... M1, early morning, doing the speed limit.

I had the same thing happen, small tapping noise, checked brake pads and discs etc, check wheel bolts... In the end I just ignored it,
Until my offside rear wheel came off at 40mph,

Turns out the garage's apprentice has snapped one of my wheel bolts with the windy gun and replaced it with one made of chinese cheese metal and cross threaded it....

Wasn't happy, sold the car over it.

[Steven_RW]

Hi - as per the other suggestions already.

1. Check wheel tightness. Just a sensible thing to do whenever you hear any suspension/speed related noises. Note: sometimes wheel bolts are nice and tight and the issue persists and it is due to hubnuts coming loose. I don't think that is your scenario.

2. Caliper bolts. I had this exact same issue on my Z4M. The top caliper bolts came loose and I was experiencing the same symptom as you are.

3. Pad retainers.

I'd vote for 2.

Cheers

Steven RW

[SuperchargedVR6]

If it's just at slow speeds, do you also get a 'clack / clunk' driving slowly up a drop kerb, or braking on steering lock?

The MK5 & MK6 Golf/A3 platform has a well publicized problem with the front subframe moving slightly under certain loads, causing the clog bashing noise. VAG attempted to fix it with some special washers that bite into the alloy, but it's not a permanent fix unfortunately.

Google 'Tyrolsport dead set' and that is a permanent solution.

If not that, it could be the brakes as you say, but surely you'd have to drive in reverse to move the pad back for it to clunk again when going forwards?