disco front brake oddness

odd fault on one of the discos.

if it's been left standing for a while, the brakes behave very much like
ones that have got a thorough soaking; lots of pedal effort and not much
stopping. This isn't AFAICS a lack of vacuum. After using the brakes a few
times, they work normally, hence I don't suspect the vacuum.

the symptoms are also similar to pad fade on overheated discs, but this
happens when the brakes are cold.

the pads only have about 3-4mm left, so I reckon I'll replace 'em, anyway,
but any ideas out there?

discs are clean and flat and correct thickness, BTW, and calipers all look
OK too.

--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
"Brevis esse laboro, Obscurus fio" (it is when I struggle to be
brief that I become obscure) Horace (65 - 8 BC) Ars Poetica, 25

Austin,

If I leave Piglet for 2 weeks he's the same. Now I know I simply blatt him
up a local straight road with no traffic and slam the anchors on a few times
until the ABS wakes up ;-)

--
Neil

On Fri, 13 Aug 2004 10:16:35 +0100, Austin Shackles
<[email protected]> wrote:

>
>odd fault on one of the discos.
>
>if it's been left standing for a while, the brakes behave very much like
>ones that have got a thorough soaking; lots of pedal effort and not much
>stopping. This isn't AFAICS a lack of vacuum. After using the brakes a few
>times, they work normally, hence I don't suspect the vacuum.
>
>the symptoms are also similar to pad fade on overheated discs, but this
>happens when the brakes are cold.
>
>the pads only have about 3-4mm left, so I reckon I'll replace 'em, anyway,
>but any ideas out there?
>
>discs are clean and flat and correct thickness, BTW, and calipers all look
>OK too.

Mine was stood for about 8 weeks and was really bad for the first mile
until I wore all the surface rust off the disks. From the symptoms it
does sound as though there's something on the friction surfaces.

Is the pedal firm throughout?

--

Tim Hobbs

'58 Series 2 88" aka "Stig"
'77 101FC Ambulance aka "Burrt"
'95 Discovery V8i aka "The Disco" (FOR SALE)
'03 Volvo V70

My Landies? http://www.seriesii.co.uk
Barcoding? http://www.bartec-systems.com
Tony Luckwill web archive at http://www.luckwill.com

Austin Shackles vaguely muttered something like ...
> odd fault on one of the discos.
>
> if it's been left standing for a while, the brakes behave very much like
> ones that have got a thorough soaking; lots of pedal effort and not much
> stopping. This isn't AFAICS a lack of vacuum. After using the brakes a
> few times, they work normally, hence I don't suspect the vacuum.
>
> the symptoms are also similar to pad fade on overheated discs, but this
> happens when the brakes are cold.
>
> the pads only have about 3-4mm left, so I reckon I'll replace 'em, anyway,
> but any ideas out there?
>
> discs are clean and flat and correct thickness, BTW, and calipers all look
> OK too.

I'd hazard a guess at air in the system .. 'thin' pads might use a fair
amount of fluid to extend the brake pistons, so unless the brake reservoir
was really full, may have drawn air in at some point. The reservoir is
generally big enough to cope with pad wear though ...

--
Paul ...

(8(|) ... Homer Rocks

"A tosser is a tosser, no matter what mode of transport they're using."

On or around Fri, 13 Aug 2004 10:57:14 +0100, Tim Hobbs
<[email protected]> enlightened us thusly:

>On Fri, 13 Aug 2004 10:16:35 +0100, Austin Shackles
><[email protected]> wrote:
>
>>
>>odd fault on one of the discos.
>>
>>if it's been left standing for a while, the brakes behave very much like
>>ones that have got a thorough soaking; lots of pedal effort and not much
>>stopping. This isn't AFAICS a lack of vacuum. After using the brakes a few
>>times, they work normally, hence I don't suspect the vacuum.
>>
>>the symptoms are also similar to pad fade on overheated discs, but this
>>happens when the brakes are cold.
>>
>>the pads only have about 3-4mm left, so I reckon I'll replace 'em, anyway,
>>but any ideas out there?
>>
>>discs are clean and flat and correct thickness, BTW, and calipers all look
>>OK too.
>
>Mine was stood for about 8 weeks and was really bad for the first mile
>until I wore all the surface rust off the disks. From the symptoms it
>does sound as though there's something on the friction surfaces.
>
>Is the pedal firm throughout?

pedal feels OK. It really does feel a lot like not enough friction -
exactly like you get if they get soaked or if you've overheated the
pads/discs enough to fade 'em. Never actually done that on a LR, but did it
once on an Audi 80. In that case the discs were old and thin.
--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
"Remember that to change your mind and follow him who sets you right
is to be none the less free than you were before."
Marcus Aurelius Antoninus (121-180), from Meditations, VIII.16

"Austin Shackles" <[email protected]> wrote in message
news:[email protected]...
>
> odd fault on one of the discos.
>
> if it's been left standing for a while, the brakes behave very much like
> ones that have got a thorough soaking; lots of pedal effort and not much
> stopping. This isn't AFAICS a lack of vacuum. After using the brakes a
few
> times, they work normally, hence I don't suspect the vacuum.
>
> the symptoms are also similar to pad fade on overheated discs, but this
> happens when the brakes are cold.
>
> the pads only have about 3-4mm left, so I reckon I'll replace 'em, anyway,
> but any ideas out there?
>
> discs are clean and flat and correct thickness, BTW, and calipers all look
> OK too.

Few possibilities, You could have some rust in the cylinder bores if the
fluid was old, leading to rough operating for a bit - check the discs arent
running hot after a couple of miles without using the brakes at all . If so
rebuild the cyls Most likely to be rust on the discs, remember powdered rust
can be a relatively good lubricant between the pads and discs until its all
worn off. There will be quite a lot of rust on the discs after more than a
week or so standing especially given the rain/humidity of late.


Andy

Andy

On or around Sat, 14 Aug 2004 22:29:17 +0100, Aled <[email protected]>
enlightened us thusly:

>In article <[email protected]>, austin@ddol-
>las.fsnet.co.uk says...
>> Never actually done that on a LR, but did it
>> once on an Audi 80.
>
>Hrm. I've done it in the Disco. I was doing about 90mph on a clear road
>[1] on the way to a shout and had to brake for the roundabout. Luckily I
>was already using engine braking a bit, but there was a sudden lurch in
>my stomach when I realised what was happenning. That's quite a steep
>hill.
>
>Cheers,
>Aled.
>
>[1] This road, I was heading downhill/southbound:
>http://www.streetmap.co.uk/streetmap.dll?G2M?X=306100&Y=204250&A=Y&Z=3

hehe.

you need vented discs.

remember a story in Trucking International a few years back, just after
someone had demolished that pub at the bottom of the hill in the Cotswolds
(Dursley? summat like that).

someone wrote in with the very valid comment that it's not the road, but the
drivers, that are dangerous. He then went on to describe the incident he'd
seen recently a the "silly roundabout" in Hemel Hempstead, (aka "ring
junction" - he was proceeding sensibly down the hill approaching same, when
he was overtaken by an artic doing about 60. As the artic reached the
bottom of the hill and the first mini-roundabout, the driver hit the brakes
and locked up all the trailer wheels, with a huge cloud of smoke, swung
around the junction with little reduction in speed, the trailer heeling over
like a racing yacht, and charged off the other side. When the narrator got
to the bottom, there were black skidmarks extending from before the first
mini-roundabout to past the second one, and there was a pal of tyre smoking
drifting in the air. The other driver had crossed about 4 give-way lines,
at such as speed that there was no possible way he could have given way.
--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
Once, when the secrets of science were the jealously guarded property of
a small priesthood, the common man had no hope of mastering their arcane
complexities. Years of study in musty classrooms were prerequisite to
obtaining even a dim, incoherent knowledge of science.
Today, all that has changed: a dim, incoherent knowledge of science is
available to anyone. - Tom Weller, Science Made Stupid, 1986

In article <[email protected]>, austin@ddol-
las.fsnet.co.uk says...
> you need vented discs.

Now, someone else has said that to me. Can I just replace the standard
LR ones? What kind of cost impact am I looking at? Also, are there any
caveats with them?

> someone wrote in with the very valid comment that it's not the road, but the
> drivers, that are dangerous.

Absolutely. I most certainly would not do those speeds on that road in
traffic. Fortunately not only was it quiet, but I was starting to break
early enough that I didn't overshoot anyway, just left a nasty brown
stain, that's all.

> He then went on to describe the incident he'd
> seen recently a the "silly roundabout" in Hemel Hempstead, (aka "ring
[...]

Er, yes. That's not good. I hope he either got nobbled for that, or it
scared the willies out of him to the point where he learned his lesson.

I know a number of lorry drivers and it's a shame that they're often
under such pressure to get a job done within a time limit that is
totally unrealistic. Most of the guys I know have had "Oh ****" moments
that have brought things into perspective and as a result are now much
happier, and calmer drivers, choosing jobs which don't require super-
human feats fo driving endurance.

Cheers,
Aled.

On Sat, 14 Aug 2004 23:50:53 +0100, Aled <[email protected]> wrote:

>In article <[email protected]>, austin@ddol-
>las.fsnet.co.uk says...
>> you need vented discs.
>
>Now, someone else has said that to me. Can I just replace the standard
>LR ones? What kind of cost impact am I looking at? Also, are there any
>caveats with them?
>

Vented disks can, reputedly, fill with mud when offroading.

Conversion is easy. Either replace the calipers with vented ones or
by a conversion kit to space out the existing ones. I went for the
latter - about £100.

If you are replacing the calipers, 110 ones are said to be the way to
go...

If you want really good Disco brakes, talk to David at Llama. I've
got his cross-drilled vented disks up front with kevlar pads and
stainless hoses. Brake performance is unrecognisable after the
conversion.


--

Tim Hobbs

'58 Series 2 88" aka "Stig"
'77 101FC Ambulance aka "Burrt"
'95 Discovery V8i aka "The Disco" (FOR SALE)
'03 Volvo V70

My Landies? http://www.seriesii.co.uk
Barcoding? http://www.bartec-systems.com
Tony Luckwill web archive at http://www.luckwill.com

In article <[email protected]>, austin@ddol-
las.fsnet.co.uk says...
> Never actually done that on a LR, but did it
> once on an Audi 80.

Hrm. I've done it in the Disco. I was doing about 90mph on a clear road
[1] on the way to a shout and had to brake for the roundabout. Luckily I
was already using engine braking a bit, but there was a sudden lurch in
my stomach when I realised what was happenning. That's quite a steep
hill.

Cheers,
Aled.

[1] This road, I was heading downhill/southbound:
http://www.streetmap.co.uk/streetmap.dll?G2M?X=306100&Y=204250&A=Y&Z=3

On or around Fri, 13 Aug 2004 10:57:14 +0100, Tim Hobbs
<[email protected]> enlightened us thusly:

>On Fri, 13 Aug 2004 10:16:35 +0100, Austin Shackles
><[email protected]> wrote:
>
>>
>>odd fault on one of the discos.
>>
>>if it's been left standing for a while, the brakes behave very much like
>>ones that have got a thorough soaking; lots of pedal effort and not much
>>stopping. This isn't AFAICS a lack of vacuum. After using the brakes a few
>>times, they work normally, hence I don't suspect the vacuum.
>>
>>the symptoms are also similar to pad fade on overheated discs, but this
>>happens when the brakes are cold.
>>
>>the pads only have about 3-4mm left, so I reckon I'll replace 'em, anyway,
>>but any ideas out there?
>>
>>discs are clean and flat and correct thickness, BTW, and calipers all look
>>OK too.
>
>Mine was stood for about 8 weeks and was really bad for the first mile
>until I wore all the surface rust off the disks. From the symptoms it
>does sound as though there's something on the friction surfaces.
>
>Is the pedal firm throughout?

pedal feels OK. It really does feel a lot like not enough friction -
exactly like you get if they get soaked or if you've overheated the
pads/discs enough to fade 'em. Never actually done that on a LR, but did it
once on an Audi 80. In that case the discs were old and thin.
--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
"Remember that to change your mind and follow him who sets you right
is to be none the less free than you were before."
Marcus Aurelius Antoninus (121-180), from Meditations, VIII.16

In article <[email protected]>, austin@ddol-
las.fsnet.co.uk says...
> you need vented discs.

Now, someone else has said that to me. Can I just replace the standard
LR ones? What kind of cost impact am I looking at? Also, are there any
caveats with them?

> someone wrote in with the very valid comment that it's not the road, but the
> drivers, that are dangerous.

Absolutely. I most certainly would not do those speeds on that road in
traffic. Fortunately not only was it quiet, but I was starting to break
early enough that I didn't overshoot anyway, just left a nasty brown
stain, that's all.

> He then went on to describe the incident he'd
> seen recently a the "silly roundabout" in Hemel Hempstead, (aka "ring
[...]

Er, yes. That's not good. I hope he either got nobbled for that, or it
scared the willies out of him to the point where he learned his lesson.

I know a number of lorry drivers and it's a shame that they're often
under such pressure to get a job done within a time limit that is
totally unrealistic. Most of the guys I know have had "Oh ****" moments
that have brought things into perspective and as a result are now much
happier, and calmer drivers, choosing jobs which don't require super-
human feats fo driving endurance.

Cheers,
Aled.

"Austin Shackles" <[email protected]> wrote in message
news:[email protected]...
>
> odd fault on one of the discos.
>
> if it's been left standing for a while, the brakes behave very much like
> ones that have got a thorough soaking; lots of pedal effort and not much
> stopping. This isn't AFAICS a lack of vacuum. After using the brakes a
few
> times, they work normally, hence I don't suspect the vacuum.
>
> the symptoms are also similar to pad fade on overheated discs, but this
> happens when the brakes are cold.
>
> the pads only have about 3-4mm left, so I reckon I'll replace 'em, anyway,
> but any ideas out there?
>
> discs are clean and flat and correct thickness, BTW, and calipers all look
> OK too.

Few possibilities, You could have some rust in the cylinder bores if the
fluid was old, leading to rough operating for a bit - check the discs arent
running hot after a couple of miles without using the brakes at all . If so
rebuild the cyls Most likely to be rust on the discs, remember powdered rust
can be a relatively good lubricant between the pads and discs until its all
worn off. There will be quite a lot of rust on the discs after more than a
week or so standing especially given the rain/humidity of late.


Andy

Andy

In article <[email protected]>, austin@ddol-
las.fsnet.co.uk says...
> Never actually done that on a LR, but did it
> once on an Audi 80.

Hrm. I've done it in the Disco. I was doing about 90mph on a clear road
[1] on the way to a shout and had to brake for the roundabout. Luckily I
was already using engine braking a bit, but there was a sudden lurch in
my stomach when I realised what was happenning. That's quite a steep
hill.

Cheers,
Aled.

[1] This road, I was heading downhill/southbound:
http://www.streetmap.co.uk/streetmap.dll?G2M?X=306100&Y=204250&A=Y&Z=3

On or around Sat, 14 Aug 2004 22:29:17 +0100, Aled <[email protected]>
enlightened us thusly:

>In article <[email protected]>, austin@ddol-
>las.fsnet.co.uk says...
>> Never actually done that on a LR, but did it
>> once on an Audi 80.
>
>Hrm. I've done it in the Disco. I was doing about 90mph on a clear road
>[1] on the way to a shout and had to brake for the roundabout. Luckily I
>was already using engine braking a bit, but there was a sudden lurch in
>my stomach when I realised what was happenning. That's quite a steep
>hill.
>
>Cheers,
>Aled.
>
>[1] This road, I was heading downhill/southbound:
>http://www.streetmap.co.uk/streetmap.dll?G2M?X=306100&Y=204250&A=Y&Z=3

hehe.

you need vented discs.

remember a story in Trucking International a few years back, just after
someone had demolished that pub at the bottom of the hill in the Cotswolds
(Dursley? summat like that).

someone wrote in with the very valid comment that it's not the road, but the
drivers, that are dangerous. He then went on to describe the incident he'd
seen recently a the "silly roundabout" in Hemel Hempstead, (aka "ring
junction" - he was proceeding sensibly down the hill approaching same, when
he was overtaken by an artic doing about 60. As the artic reached the
bottom of the hill and the first mini-roundabout, the driver hit the brakes
and locked up all the trailer wheels, with a huge cloud of smoke, swung
around the junction with little reduction in speed, the trailer heeling over
like a racing yacht, and charged off the other side. When the narrator got
to the bottom, there were black skidmarks extending from before the first
mini-roundabout to past the second one, and there was a pal of tyre smoking
drifting in the air. The other driver had crossed about 4 give-way lines,
at such as speed that there was no possible way he could have given way.
--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
Once, when the secrets of science were the jealously guarded property of
a small priesthood, the common man had no hope of mastering their arcane
complexities. Years of study in musty classrooms were prerequisite to
obtaining even a dim, incoherent knowledge of science.
Today, all that has changed: a dim, incoherent knowledge of science is
available to anyone. - Tom Weller, Science Made Stupid, 1986

On Sat, 14 Aug 2004 23:50:53 +0100, Aled <[email protected]> wrote:

>In article <[email protected]>, austin@ddol-
>las.fsnet.co.uk says...
>> you need vented discs.
>
>Now, someone else has said that to me. Can I just replace the standard
>LR ones? What kind of cost impact am I looking at? Also, are there any
>caveats with them?
>

Vented disks can, reputedly, fill with mud when offroading.

Conversion is easy. Either replace the calipers with vented ones or
by a conversion kit to space out the existing ones. I went for the
latter - about £100.

If you are replacing the calipers, 110 ones are said to be the way to
go...

If you want really good Disco brakes, talk to David at Llama. I've
got his cross-drilled vented disks up front with kevlar pads and
stainless hoses. Brake performance is unrecognisable after the
conversion.


--

Tim Hobbs

'58 Series 2 88" aka "Stig"
'77 101FC Ambulance aka "Burrt"
'95 Discovery V8i aka "The Disco" (FOR SALE)
'03 Volvo V70

My Landies? http://www.seriesii.co.uk
Barcoding? http://www.bartec-systems.com
Tony Luckwill web archive at http://www.luckwill.com