Knocking noise from Disco rear brakes

I'll try to keep this brief. I'm looking for advice along the lines
of "Take it straight back and complain" or "Sounds fair enough".

1997 Discovery TDi ES (ABS. Solid discs)

On Friday I had new brake discs all round, new brake pads all round
and new brake pipes. A main dealer did the job and it cost a packet.
The vehicle wasn't ready at the agreed time because they'd had trouble
and were still road-testing it.

Apparently, on the first road test they heard a knocking from the rear
brakes. This was due to "the pads needing to be de-glazed. Something
on the pads must be causing them to stick to the discs and then jump
off, making a knocking noise." This happens occasionally, apparently,
so they took some sandpaper to the pads, reassembled everything and
took it out on another road test. There was still a knocking noise.
So, they sanded the pads again ....... and again.

They then advised me that this has happened once before in their
workshop and they reckon the new discs and pads just need a few more
miles to bed in. The last fella was OK after a couple of days! If
it's still knocking after a couple of days I should bring it back in,
just in case there's a faulty disc or something.

This seemed like a reasonable story at the time, so I drove the 50
miles home. I didn't drive like a maniac but I didn't dawdle either.
It was just a normal journey but I was aware that my brakes may
feel/respond differently to normal so I allowed a bit more space to
brake. I listened very carefully everytime I applied the brakes but
heard nothing until I was about three miles from home. I was braking
at a Give Way line when I heard a slow-ish knock-knock-knock-knock
from the back end.

I've done another 60 miles since then and have not heard the noise
again.

What do you think? With hindsight I feel I should have said "It
didn't do that when I brought it in, so I'm not paying till you've
sorted it". However, there doesn't seem to be any problem with the
brakes, ie the braking is fine although I haven't yet tried a
high-speed (over 50mph) brake, and I haven't heard the noise since
Friday.

Any thoughts?

Judith

On Mon, 07 Feb 2005 21:43:58 +0000, Judith
<[email protected]> wrote:

>I'll try to keep this brief. I'm looking for advice along the lines
>of "Take it straight back and complain" or "Sounds fair enough".
>
snip

I dont think you're in any danger of failure.
If they had the pads out several times then they are most likely put
back in properly. I've had brakes make strange noises after relining /
new bits fitted, but its always gone away eventually.
I think its a case of suck it and see, but I would write to the
dealership who did the work telling them what you told us, 'just for
the record' so if the knock comes back you have something to beat them
with.

--
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>
> I dont think you're in any danger of failure.
> If they had the pads out several times then they are most likely put
> back in properly. I've had brakes make strange noises after relining /
> new bits fitted, but its always gone away eventually.
> I think its a case of suck it and see, but I would write to the
> dealership who did the work telling them what you told us, 'just for
> the record' so if the knock comes back you have something to beat them
> with.


Hate to be controversal but I would be less inclined to trust a dealer than
an independant. Less loyalty, more time pressure, less need to keep good
name.
Once had a brake set up sorted at a main Renault agent and after a day or so
of overheating rear drum discovered they had left a clamp on the pipe
allowing fluid into system under pressure but no return due to restriction.
Took in offending clamp on the Monday and had a quiet word with WS manager.
Same place 'serviced ' the car and ended up having to return as some little
oik had filled the power fluid box to the brim instead of the full mark (
despite being told that I had checked levels before they got their mits on
it ).

In message <[email protected]>
Colonel Tupperware <[email protected]> wrote:

> On Mon, 07 Feb 2005 21:43:58 +0000, Judith
> <[email protected]> wrote:
>
> >I'll try to keep this brief. I'm looking for advice along the lines
> >of "Take it straight back and complain" or "Sounds fair enough".
> >
> snip
>
> I dont think you're in any danger of failure.
> If they had the pads out several times then they are most likely put
> back in properly. I've had brakes make strange noises after relining /
> new bits fitted, but its always gone away eventually.
> I think its a case of suck it and see, but I would write to the
> dealership who did the work telling them what you told us, 'just for
> the record' so if the knock comes back you have something to beat them
> with.
>
Obviously it alsmost impossible to make a "proper" diagnosis
without seeing the vehicle, but I'd go along with the above.
I'd hazard a guess that the discs have a "sticky bit" of the
gunge that they are protected with for storage, and the
knocking is the pad "hitting" this and jumping a bit. As you
seem to have observed, if that is the cause it will go away
with use.

Richard

--
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beamendsltd wrote:

> Obviously it alsmost impossible to make a "proper" diagnosis
> without seeing the vehicle, but I'd go along with the above.
> I'd hazard a guess that the discs have a "sticky bit" of the
> gunge that they are protected with for storage, and the
> knocking is the pad "hitting" this and jumping a bit.

Sort of says it all about their workmanship if they are too ignorant or
idle to clean the new discs off before fitting them doesn't it.


--
EMB

In article <[email protected]>, EMB <[email protected]> writes
>Sort of says it all about their workmanship if they are too ignorant or
>idle to clean the new discs off before fitting them doesn't it.

Genuine landrover Discs come with a very hard protective paint that is a
sod to get off. The best way to remove it is to fit to the vehicle and
let the brake pads do it for you.

marc wrote:

> Genuine landrover Discs come with a very hard protective paint that is a
> sod to get off. The best way to remove it is to fit to the vehicle and
> let the brake pads do it for you.

Lacquer thinners and scotch brite has always worked for me. The
accpeted trade practice is that discs are *clean* before use - and when
playing with something as important as brakes you should get things
perfect every time.


--
EMB

On Wed, 09 Feb 2005 07:51:52 +1300, EMB <[email protected]> wrote:

>> Obviously it alsmost impossible to make a "proper" diagnosis
>> without seeing the vehicle, but I'd go along with the above.
>> I'd hazard a guess that the discs have a "sticky bit" of the
>> gunge that they are protected with for storage, and the
>> knocking is the pad "hitting" this and jumping a bit.
>
>Sort of says it all about their workmanship if they are too ignorant or
>idle to clean the new discs off before fitting them doesn't it.

Hm? That's what I was thinking.

I've done another 50 miles today and haven't heard or felt anything
strange.

It's probably all OK.

Thanks for all your comments.

Judith

In article <[email protected]>, EMB <[email protected]> writes
>Lacquer thinners and scotch brite has always worked for me. The
>accpeted trade practice is that discs are *clean* before use - and when
>playing with something as important as brakes you should get things
>perfect every time.


In the old days you could just degrease them with brake cleaner. nice a
quick.

Now do you want to pay the £80+VAT per hour for some oily rag to polish
the protective coating of your discs ?

Interestingly enough all other makes of LR discs still come lightly
greased even the OE ones. I keep both on the shelf

marc wrote:

> In the old days you could just degrease them with brake cleaner. nice a
> quick.
>
> Now do you want to pay the £80+VAT per hour for some oily rag to polish
> the protective coating of your discs ?

Given that it takes maybe 5 minutes to clean a pair, yes I do. As a
customer even at 7 quids worth of labour it's cheap compared to all the
hassle and worry of strange braking noises. As a workshop proprietor I
certainly want it done - I don't want complaints, reworks and worry from
the customers, otherwise they'll spread their story and then my business
will lose it's reputation for being "Not the cheapest garage, but bloody
good mechanics and value for money" as it was put by one of my customers.


--
EMB

In message <[email protected]>
EMB <[email protected]> wrote:

> beamendsltd wrote:
>
> > Obviously it alsmost impossible to make a "proper" diagnosis
> > without seeing the vehicle, but I'd go along with the above.
> > I'd hazard a guess that the discs have a "sticky bit" of the
> > gunge that they are protected with for storage, and the
> > knocking is the pad "hitting" this and jumping a bit.
>
> Sort of says it all about their workmanship if they are too ignorant or
> idle to clean the new discs off before fitting them doesn't it.
>
>
Indeed....

Richard
--
www.beamends-lrspares.co.uk [email protected]
Running a business in a Microsoft free environment - it can be done
Powered by Risc-OS - you won't get a virus from us!!
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