Brake Pad Malfunction.

[St Thicket]

My wife suddenly noticed a scraping sound from the front left wheel when braking. Sometimes the sound kept on even though she had taken her foot off the brake pedal. She thought it was annoying so she asked me to take a look...

I took a quick look at the brake disk on saturday, and noticed some nasty grooves... My first thought was that it might be a small stone that had gotten between the pad and the disk, but after thinking about it for a couple of minutes, it seemed quite unlikely, because it is not much space between the two to allow something between that could cause those kinds of sounds (and grooves).

I went to the other wheel to compare, and then it struck me: The friction pad was completely gone! What the F! How could that happen? I had the pads changed in May!

Should I be angry with my friend that changed my pads, or can this happen to any brake pad?

Do I have to change my disks as well, now that it has been unevenly worn?

I don't have much knowledge about mechanical issues, so I would appreciate any comment!

[dave.m]

Changed in MAY sure he did not put the old ones back in ? How many miles since May ?

[St Thicket]

Changed in MAY sure he did not put the old ones back in ? How many miles since May ?

Probably around 15000 km (10000 miles)

And no... I saw the new pads... in their box. They were completely and utterly NEW.

[three5]

Changed in MAY sure he did not put the old ones back in ? How many miles since May ?

Probably around 15000 km (10000 miles)

And no... I saw the new pads... in their box. They were completely and utterly NEW.

Anchorman is the guy for this one, but he has probably had to go to work. It sounds as though the bond between the friction material and the backing plate might have broken down and the friction material has become displaced. Were they genuine Toyota brakepads?

Seem to remember that you did a long trip in the summer. Did that involve a lot of long decents that could have worn out the pads?

[moonstone mart]

Can you see if both of the brake pads on that side are worn completely or just the outer?

Possibility of siezed caliper therefore causing excessive wear on the pads or as said above the pad material could have come away from the metal plate and fell out.

If the discs are very grooved you would be better off replacing the discs aswell as pads.

Were they genuine Toyota or pattern parts?

Mart.

[St Thicket]

Were they genuine Toyota brakepads?

Yes, they were bought at my local toyota dealer. They came in a Toyota branded box. But if they were genuine? I don't know. I doubt they were manufactured by Toyota :P

Seem to remember that you did a long trip in the summer. Did that involve a lot of long decents that could have worn out the pads?

I am very cautious when descending mountains, and I always brake short intervals rather than holding the brake in for a long period of time. I always use low gears and let the engine limit my speed. Even when I drive in rush hour traffic, I rarely use the brakes. I tend to use the clutch and the gears to reduce my speed, probably to a great annoyance to the drivers behind. They must think my brake lights are faulty

[St Thicket]

Can you see if both of the brake pads on that side are worn completely or just the outer?

I haven't bothered looking on the inner side, mostly because it is freezing outside, and it requires me to lay down on an icy road with a torch... Doesn't appeal to me when I can be inside reading a book and drinking a beer :)

Possibility of siezed caliper therefore causing excessive wear on the pads or as said above the pad material could have come away from the metal plate and fell out.

I don't know. All I know is that it happened suddenly. Both sides were changed at the same time, and the right side brake pad has probably at least 10 mm of friction material left.

[anchorman]

Okey Dokey!

Thanks three 5 I was out at work and those rails are slippy at the moment!!! I now know I can clench my buttocks so tight that I snatch the seat cover off when I stand up. Duncs will know what I mean.

Where were we? Oh yes brake pads!!

Now having been informed that they were genuine Toyota pads I can tell you immediately that there is something radically wrong with the vehicle - as I ve said before, in 17 years of brake testing and development I never came across any pads better than those.

There is one thing and one thing only that causes premature pad wear in anything better than reasonable quality brake pads and that is temperature. The resin system that binds the fillers begins to break down rapidly at temperatures in excess of 400 deg C. To give you some idea the disc will glow cherry red at around 550 deg C. This is usually accompanied by a resinous smell and even wisps of bluish smoke. However, it may not have raised alarm bells with your wife.

The pad is fitted with an "audible wear indicator" which is nothing more than a bent piece of spring steel and resonates when it contacts the disc - this is what you heard screaching.

It seems that you have had a pad stuck in the caliper. I cannot imagine that all four are worn out but if they are it would suggest the rears are hardly working at all (not as obvious as you might think as 70% of the work is done by the fronts on a "healthy" vehicle). Some manufacturers had problems with Lucas calipers where they missed a coining operation during manufacture (where they force a die through the casting to ensure the clearance) and this caused pads to stick in service. The calipers are also fitted with stainless steel guide clips which are fiddley and maybe your garage got one twisted.

To summarise, I don't suspect faulty pads for one minute and I think an inspection of the brakes will quickly identify the problem once you can get it into a workshop out of the cold.

I wonder if they do train driver sized Pampers???

[bothwell_buyer]

anchorman - just pamper yersel and don't give us more info!!!

On the brakes - I'm no lover of Toyota calipers and the best thing i ever did was get rid of a set. The pistons/caliper sticks and ruins the disc and the pad.

You can only buy discs in pairs. The minimum thickness of the disc is cast into the inside of the disc so you know whether they can be skimmed. A disc is generally a lump of steel no matter where it comes from. The pads make a difference. Theres been a few posts on here relating to this.

Just buy yer wife an anchor and a rope and tell her to tie the rope round the waist and the other end round the anchor....and when a stopping action is required, throw the anchor towards a passing snowman! I know you have them cos I've watched "Where Eagles dare".

[St Thicket]

I now know I can clench my buttocks so tight that I snatch the seat cover off when I stand up.

Now having been informed that they were genuine Toyota pads I can tell you immediately that there is something radically wrong with the vehicle - as I ve said before, in 17 years of brake testing and development I never came across any pads better than those.

There is one thing and one thing only that causes premature pad wear in anything better than reasonable quality brake pads and that is temperature. The resin system that binds the fillers begins to break down rapidly at temperatures in excess of 400 deg C. To give you some idea the disc will glow cherry red at around 550 deg C. This is usually accompanied by a resinous smell and even wisps of bluish smoke. However, it may not have raised alarm bells with your wife.

The pad is fitted with an "audible wear indicator" which is nothing more than a bent piece of spring steel and resonates when it contacts the disc - this is what you heard screaching.

This must have happened over time, since we never smelled anything. But then again, we should have heard some screaching, but my wife said that the car acted normal until she suddenly heard an intense scratching sound.

It seems that you have had a pad stuck in the caliper. I cannot imagine that all four are worn out but if they are it would suggest the rears are hardly working at all (not as obvious as you might think as 70% of the work is done by the fronts on a "healthy" vehicle). Some manufacturers had problems with Lucas calipers where they missed a coining operation during manufacture (where they force a die through the casting to ensure the clearance) and this caused pads to stick in service. The calipers are also fitted with stainless steel guide clips which are fiddley and maybe your garage got one twisted.

That might be a thought... However, if this would be the result of excessive wear due to caliper malfunction, then we would hear some screaching in time before the pads were completely worn out?

Just buy yer wife an anchor and a rope and tell her to tie the rope round the waist and the other end round the anchor....and when a stopping action is required, throw the anchor towards a passing snowman! I know you have them cos I've watched "Where Eagles dare".

Thanks for your advice

[three5]

Thanks three 5 I was out at work and those rails are slippy at the moment!!! I now know I can clench my buttocks so tight that I snatch the seat cover off when I stand up. Duncs will know what I mean.

I wonder if they do train driver sized Pampers???

.........now if we can just think of a way of using all that clenching energy to grip the rail, we might be on the way to a solution! ( sorry Anchorman ). Passengers might take a dim view of cadence braking. It's bloomin' easy to smile at someone elses discomfort.

Just had a bit of a thought: Winter, slippy roads, braking.

As part of a driving course many (many, many ) years ago, I spent a very educational afternoon on a skid-pan. It removes many of the terrors of driving in bad conditions ( buttock clenching etc ). Steering into the skid and cadence braking become an involuntary reaction. I know that most of us have ABS these days, but how about a group outing ( meet ) to a skid-pan?

[bothwell_buyer]

Thanks three 5 I was out at work and those rails are slippy at the moment!!! I now know I can clench my buttocks so tight that I snatch the seat cover off when I stand up. Duncs will know what I mean.

I wonder if they do train driver sized Pampers???

.........now if we can just think of a way of using all that clenching energy to grip the rail, we might be on the way to a solution! ( sorry Anchorman ). Passengers might take a dim view of cadence braking. It's bloomin' easy to smile at someone elses discomfort.

Just had a bit of a thought: Winter, slippy roads, braking.

As part of a driving course many (many, many ) years ago, I spent a very educational afternoon on a skid-pan. It removes many of the terrors of driving in bad conditions ( buttock clenching etc ). Steering into the skid and cadence braking become an involuntary reaction. I know that most of us have ABS these days, but how about a group outing ( meet ) to a skid-pan?

All for that - there's one called the M6 !

[St Thicket]

I've thought about this issue for a while now, and I think I know why this might have happened...

Sometimes I've heard a braking sound even though the brakes aren't active (but have been recently used). Sometimes when I let the car roll with the clutch in, then it seems like there's been some friction somewhere... I've always thought that it might have been due to the heavy weight of the car. Now I think that it might be the caliper on the front wheel that might be faulty so that the pad have been barely touching the disk for a long time. The heat produce over the long period of time must then have damaged the pad in a way so that the friction material must have lost it's binding to the steel.

This sounds like the most probable explanation that I can find.

[anchorman]

Thanks three 5 I was out at work and those rails are slippy at the moment!!! I now know I can clench my buttocks so tight that I snatch the seat cover off when I stand up. Duncs will know what I mean.

I wonder if they do train driver sized Pampers???

.........now if we can just think of a way of using all that clenching energy to grip the rail, we might be on the way to a solution! ( sorry Anchorman ). Passengers might take a dim view of cadence braking. It's bloomin' easy to smile at someone elses discomfort.

Just had a bit of a thought: Winter, slippy roads, braking.

As part of a driving course many (many, many ) years ago, I spent a very educational afternoon on a skid-pan. It removes many of the terrors of driving in bad conditions ( buttock clenching etc ). Steering into the skid and cadence braking become an involuntary reaction. I know that most of us have ABS these days, but how about a group outing ( meet ) to a skid-pan?

All our drivers go to the Kirkby line for a day (on Sunday when it is closed) and practice skid pan training with a DMU that can squirt a slippy substance on the rail. We practice cadence braking, or a very slow version of it under these conditions.

Moving off the rails I would be very interested in such an event. I have been driving for 33 years and am not entirely convinced I would react in the best way if I got into a true uncontrolled skid.

I'm up for it - good idea.

[local hero]

Count me in, just googled skid pan courses loads of options, we will have to get a list of those interested find a central location, pick a day + then haggle a group price, will they teach me to drift like the STIG?

[Hoovie]

I just ripped up my voucher for a Skid Pan session about 3 hours ago as it happens

Got one when I left my last company in 2000 and forgot to use it ... Duh!

I'd be up for this long as it is somewhere normal! (Devon, maybe? ;) )

[local hero]

I'd be up for this long as it is somewhere normal! (Devon, maybe? ;) )

Whats normal about Devon? Don't you dress up in funny clothes and dance around with sticks with bells on the end, and call us furriners Grockles?

or is that Cornwall? Anyway i know its Three 5s Idea but i think we should find out who's interested, the area they live, and try to find somewhere central to those who are interested and if theres a lot of interest we may need to have a meet OOOP NORF + one DARN SARF

[shcm]

Although I'm only one of the "backroom" design Engineers, very occasionally situations arise where we have to go out with a test vehicle. So, in the interests of safety, some years ago the company chucked quite a few of us on an advanced driving course.

That included skid pan stuff at the Staffordshire Police facility in Hixon. Some pictures here:

http://photos.holosys.co.uk/a/2728

To be honest, those pictures make it look bigger than it actually is and you lot might want somewhere with a bit more SPEED.

Nevertheless, it was great fun. The usual cadence breaking stuff and other useful techniques. A real eye opener with a vehicle with switchable ABS, so you could see the benefits for yourself with ABS both on and off.

Moving off the rails I would be very interested in such an event. I have been driving for 33 years and am not entirely convinced I would react in the best way if I got into a true uncontrolled skid.

A chap at work who races at the weekends admits he's not sure he'd react in the best way on a normal road. He reckons whoever you are, you always more prepared for it on a track than in "real life". I can see his point. As you are well aware though, some of those test drivers are still quite impressive on the road.

Count me in, just googled skid pan courses loads of options, we will have to get a list of those interested find a central location, pick a day + then haggle a group price, will they teach me to drift like the STIG?

As you say mate, lots of places:

http://www.advanced-driving.co.uk/skid-pan-courses/

I'd be up for it, so long as I don't have to use me RAV!

[three5]

I'd be up for this long as it is somewhere normal! (Devon, maybe? ;) )

Whats normal about Devon? Don't you dress up in funny clothes and dance around with sticks with bells on the end, and call us furriners Grockles?

or is that Cornwall? Anyway i know its Three 5s Idea but i think we should find out who's interested, the area they live, and try to find somewhere central to those who are interested and if theres a lot of interest we may need to have a meet OOOP NORF + one DARN SARF

I suppose I'd better admit I'd definitely be interested if we can find somewhere suitable. When I went last time it was a place near York and it was an old type of set-up with old engine oil and water on a figure of eight circuit. After a few laps you could just hold the steering wheel still and steer with the throttle. Should be right up Anchorman's street as he is not used to steering his train! They used Mk II Cortinas with the brakes backed right off for practice. Don't know if they sprayed the oil on or just drove a Land Rover round for a few laps to create the surface.

I think that that modern pans use some sort of soap with water which would make a good job of washing the underside of the motor but wouldn't "underseal" it in the same way as old oil.

[Hoovie]

You know what I have been musing about actually .... maybe an weekend meet around the lake district? you can rent a complete youth hostels cheaply for a weekend, pubs in evening, interesting moutain passes during day, combine with skidpan event?

[bothwell_buyer]

Count me in, just googled skid pan courses loads of options, we will have to get a list of those interested find a central location, pick a day + then haggle a group price, will they teach me to drift like the STIG?

Hmmmmmmmmmmmmmmmmmmmmmmmmmmmm

will they manage to fit you into Stigs race suit??? :P :P

[bothwell_buyer]

Although I'm only one of the "backroom" design Engineers, very occasionally situations arise where we have to go out with a test vehicle. So, in the interests of safety, some years ago the company chucked quite a few of us on an advanced driving course.

That included skid pan stuff at the Staffordshire Police facility in Hixon. Some pictures here:

http://photos.holosys.co.uk/a/2728

To be honest, those pictures make it look bigger than it actually is and you lot might want somewhere with a bit more SPEED.

Nevertheless, it was great fun. The usual cadence breaking stuff and other useful techniques. A real eye opener with a vehicle with switchable ABS, so you could see the benefits for yourself with ABS both on and off.

Moving off the rails I would be very interested in such an event. I have been driving for 33 years and am not entirely convinced I would react in the best way if I got into a true uncontrolled skid.

A chap at work who races at the weekends admits he's not sure he'd react in the best way on a normal road. He reckons whoever you are, you always more prepared for it on a track than in "real life". I can see his point. As you are well aware though, some of those test drivers are still quite impressive on the road.

Count me in, just googled skid pan courses loads of options, we will have to get a list of those interested find a central location, pick a day + then haggle a group price, will they teach me to drift like the STIG?

As you say mate, lots of places:

http://www.advanced-driving.co.uk/skid-pan-courses/

I'd be up for it, so long as I don't have to use me RAV!

No problem - I'll use it :lol:

[bothwell_buyer]

I've thought about this issue for a while now, and I think I know why this might have happened...

Sometimes I've heard a braking sound even though the brakes aren't active (but have been recently used). Sometimes when I let the car roll with the clutch in, then it seems like there's been some friction somewhere... I've always thought that it might have been due to the heavy weight of the car. Now I think that it might be the caliper on the front wheel that might be faulty so that the pad have been barely touching the disk for a long time. The heat produce over the long period of time must then have damaged the pad in a way so that the friction material must have lost it's binding to the steel.

This sounds like the most probable explanation that I can find.

Back in pad-land ----------

I had big problems with the blkg calipers sticking and ruining the discs - cost me a fortune which is why I spent a fortune changing to 6 pot racing calipers. At least now the brakes work, as some found out earlier this year. MOT due in 2 weeks but all should be well.

[local hero]

Count me in, just googled skid pan courses loads of options, we will have to get a list of those interested find a central location, pick a day + then haggle a group price, will they teach me to drift like the STIG?

Hmmmmmmmmmmmmmmmmmmmmmmmmmmmm

will they manage to fit you into Stigs race suit??? :P :P

Well I am so polite Bothy i didn't know how to broach this, but two of the courses i have seen set a weight limit of 18st, so for some people this will not be so much a crash avoidance course, as a crash diet course..

[three5]

Thanks three 5 I was out at work and those rails are slippy at the moment!!! I now know I can clench my buttocks so tight that I snatch the seat cover off when I stand up. Duncs will know what I mean.

I wonder if they do train driver sized Pampers???

.........now if we can just think of a way of using all that clenching energy to grip the rail, we might be on the way to a solution! ( sorry Anchorman ). Passengers might take a dim view of cadence braking. It's bloomin' easy to smile at someone elses discomfort.

Just had a bit of a thought: Winter, slippy roads, braking.

As part of a driving course many (many, many ) years ago, I spent a very educational afternoon on a skid-pan. It removes many of the terrors of driving in bad conditions ( buttock clenching etc ). Steering into the skid and cadence braking become an involuntary reaction. I know that most of us have ABS these days, but how about a group outing ( meet ) to a skid-pan?

All our drivers go to the Kirkby line for a day (on Sunday when it is closed) and practice skid pan training with a DMU that can squirt a slippy substance on the rail. We practice cadence braking, or a very slow version of it under these conditions.

Moving off the rails I would be very interested in such an event. I have been driving for 33 years and am not entirely convinced I would react in the best way if I got into a true uncontrolled skid.

I'm up for it - good idea.

Could we give the skid-pan meet a new title in the forum as in it's current position it is likely to be missed by some of the members? I like Hoovie's idea of a Lake District weekend. February is always a good time in the Lakes and we probably won't need to hire a skid-pan! ;)