Knocking noise & caliper pins..

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norris_309

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Hi Guys,

In my quest to find a knocking noise on the front of my a4 avant I came across a forum post that described my issue to a 'T'

http://www.audi-sport.net/xf/threads/knocking-noise.151279/

the conclusion of that was the slider pins in the caliper.

Now there isn't much in the way of a description as to what was actually wrong with them, so I took each slider pin out today whilst I had a look around the suspension arms/springs etc.., i cleaned them off & copper greased them up & re-fitted.

They all came off fine & went back on fine & can't see anything that looks wrong about them or the caliper, and this hasn't done a damn thing!..

Is there anything else I should have done to them??.. also i'm struggling to see how would a slider pin make a knocking noise anyway? any thoughts?

Cheers
 
Think it's more to do with the pins sticking coz they're corroded or jammed up then the brake pads rattle about slightly because the caliper can't properly contact them. This was certainly the case with my B5 when I had a troublesome rattle.
 
I had brake noise/caliper rattle on my A4 last week so I removed the calipers and copper greased the back of all the brake pads, the caliper groove that the pad sits into and also the slider pins, whilst I was there I also copper greased behind the brake discs to the hub. No noise whatsoever now from the brakes!
 
ANDYMC_TQS said:
Are you sure it's the brakes making the noise
Click to expand...

No not sure at all... I've had a odd knocking noise from the front end since around September/November time.
I've changed drop links, and lower suspension arms as they were showing signs.

but still doing it, nothing picked up on MOT.

And it was only when I read a thread on here from 2012, which described the knocking sound mine does to a T, and to outcome was the slide pins.
So thought i'd take a look yesterday, as at least it was a quick free thing to try.
My main reason for the thread was checking there wasn't anything else I should have done extra to cleaning them off & re-greasing them.

I'm wondering, I probably should have just taken the lot apart & cleaned up the calipers etc.. just to rule it out more than anything, but I've got a stinking cold & it ain't warm out on the drive!!... maybe another day.
 
Yeah I wouldn't be tempted in this weather either. Is the noise only when you go over bump or is it worse when turning or braking
 
norris_309 said:
No not sure at all... I've had a odd knocking noise from the front end since around September/November time.
I've changed drop links, and lower suspension arms as they were showing signs.

but still doing it, nothing picked up on MOT.

And it was only when I read a thread on here from 2012, which described the knocking sound mine does to a T, and to outcome was the slide pins.
So thought i'd take a look yesterday, as at least it was a quick free thing to try.
My main reason for the thread was checking there wasn't anything else I should have done extra to cleaning them off & re-greasing them.

I'm wondering, I probably should have just taken the lot apart & cleaned up the calipers etc.. just to rule it out more than anything, but I've got a stinking cold & it ain't warm out on the drive!!... maybe another day.
Click to expand...

You changed the lower arms, this requires the subframe to be dropped at the back, chances are the bolts are either not tight enough or they need replaced, they are stretch bolts and supposedly one use only, try nipping them up a little tighter first.
 
On your advice I have put a spanner on the 2 (per side) sub frame bolts, from looking I think I got the right ones, they are near the inner end of the lower rear control arms. (and look like they'd be the ones to loosen to undo the control arm bolt)
They were tight on there, I couldn't tighten them up. at least I have the peace of mind that they're not loose now if nothing else.

I think I'm clutching at straws with it really, the inner rubber on 2 of the upper arms had a slight crack in it. couldn't get them to budge by leverage, but I guess chances are it 'might' be them.

I'm trying to solve this without risking spending/wasting too much money!... it ain't going to happen is it.
 
norris_309 said:
On your advice I have put a spanner on the 2 (per side) sub frame bolts, from looking I think I got the right ones, they are near the inner end of the lower rear control arms. (and look like they'd be the ones to loosen to undo the control arm bolt)
They were tight on there, I couldn't tighten them up. at least I have the peace of mind that they're not loose now if nothing else.

I think I'm clutching at straws with it really, the inner rubber on 2 of the upper arms had a slight crack in it. couldn't get them to budge by leverage, but I guess chances are it 'might' be them.

I'm trying to solve this without risking spending/wasting too much money!... it ain't going to happen is it.
Click to expand...

Could be at the balljoint end though, a cheap set for less than £40 http://www.ebay.co.uk/itm/AUDI-A4-A...056616?hash=item3f2171f728:g:cpYAAMXQUmFSp0sS
 
ANDYMC_TQS said:
Yeah I wouldn't be tempted in this weather either. Is the noise only when you go over bump or is it worse when turning or braking
Click to expand...

The noise is an odd one really.. it doesn't tend to do it over speed bumps (not consistently anyway, if it does it'll do it on the way down the bump.
It tends to be more often when going over uneven ground.. so slight bumps & it seems to be worse when turning left.
And doesn't tend to do it when braking.

the fact it does it coming down off a bump makes me wonder... (i'm not sure what about mind you lol)

It also doesn't do it all the time, which makes it worse as I had a mechanic mate take it for a drive (he weighs a fair bit more than me!) and it didn't do it once! not sure if the weight was relevant or not!. he looked at it on a ramp for me & found the 2 front lower rear arms had the rubber coming away from the metal on the inner part, so thought that must be it.. so changed them, only for it to be exactly the same!

in the past I've also changed the lower front arm on the passenger side (drivers side still looks fine)

I've changed the anti roll bar links in July last year as they were an mot advisory & all was quiet for 2 or 3 months, then when I was on holiday I turned into a parking space on a slope & something went 'bang' & the knocking has been on & off since.

Sorry i'm rambling now,...
 
norris_309 said:
The noise is an odd one really.. it doesn't tend to do it over speed bumps (not consistently anyway, if it does it'll do it on the way down the bump.
It tends to be more often when going over uneven ground.. so slight bumps & it seems to be worse when turning left.
And doesn't tend to do it when braking.

the fact it does it coming down off a bump makes me wonder... (i'm not sure what about mind you lol)

It also doesn't do it all the time, which makes it worse as I had a mechanic mate take it for a drive (he weighs a fair bit more than me!) and it didn't do it once! not sure if the weight was relevant or not!. he looked at it on a ramp for me & found the 2 front lower rear arms had the rubber coming away from the metal on the inner part, so thought that must be it.. so changed them, only for it to be exactly the same!

in the past I've also changed the lower front arm on the passenger side (drivers side still looks fine)

I've changed the anti roll bar links in July last year as they were an mot advisory & all was quiet for 2 or 3 months, then when I was on holiday I turned into a parking space on a slope & something went 'bang' & the knocking has been on & off since.

Sorry i'm rambling now,...
Click to expand...

Did you change the rubber bushes where the anti roll bar bolts to the subframe, that's where I'd look.
 
QuattroCalum said:
Could be at the balljoint end though, a cheap set for less than £40 http://www.ebay.co.uk/itm/AUDI-A4-A...056616?hash=item3f2171f728:g:cpYAAMXQUmFSp0sS
Click to expand...

Yeah I think you are right.. I'm going to have to bite the bullet at some point!..
Although i'm a bit reluctant to buy the cheaper suspension parts after bad experiences with them in the past resulting in issues within a few months & having to re-do them, guess it all depends on labour cost whether it's worth the risk I suppose.
I don't fancy doing the upper ones myself, looks like a bit of a pain!

I've been using lemforder & TRW on the lower so would probably go for them for the uppers, then with the labour... it gets pretty expensive.
If I knew it'd cure it for definite they'd be done tomorrow.. but after the lowers looking like a definite & not being... i'm slightly unsure.

But they'll need to be done to rule out if nothing else.!
 
QuattroCalum said:
Did you change the rubber bushes where the anti roll bar bolts to the subframe, that's where I'd look.
Click to expand...

That's a fair shout, I did wonder whether by changing the roll bar links before, them being stiff may have put more pressure on some older worn parts causing this.
I take it there are 2 rubbers under (above) the under trays more to the middle?.. do you know if you can you buy the rubber bushes or is it a new roll bar?

I'll have to take a look, never taken the under trays off before.

When it does a bigger/louder bang (as it varies) you can kind of feel it in the footwells... and it seems to be both sides so was wondering about the anti roll bar itself, but kind of thought it's just a metal bar so what could be wrong!
 
I can only suggest doing the anti roll bar bushes first as they are the cheapest and easiest to change.
Use whichever arms suit your budget, lots of bush failures can be due to not setting the arm position correctly before tightening the bolts, stressing the bushes.
 
nice one, thanks for the advice.. i'll take a look at those when I can.
Really appreciate it.
 
As you say it's worse coming off bumps id be thinking of the top mounts. I had a car a few weeks ago with exactly the same problem, very noticeable knock, had lower arms drop links and springs (as were snapped) and it all turned out to be the top mount
 
I guess there's no real way of knowing without removing the shocks that they're gone is there??

I remember on my mk4 golf the top mounts were shot, you could see that from under the bonnet as they were sticking up a lot more on one side!... didn't have any noticeable knocks mind you.

The mrs is away in the audi this weekend so can't have a look at the moment.

But when the weather is a bit warmer i'll be removing the under tray & checking/replacing the anti roll bar bushes & see if there is anything I can see/check with the top mounts.
 
well an update....
The car failed the MOT last weekend, on... the nearside anti roll bar link!..
I changed that last July as it was an advisory, I used the Lemforder links as well.
I took off the 'failed' drop link & it actually looked fine.. (but then it had only been on for 8 months/ 6k miles), I changed it and guess what.. the knocking stopped!

I ruled that out as a cause of the knocking as i didn't use the cheap drop links!... so annoyed but kind of glad to be fair.
I nearly went down the route of changing the top control arms as they're looking a little worn, so at least it was a cheap fix! (plus got money back on the duff one)
So a lesson learnt..
 
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