Brake lining wear

[ashwaads]

Morning all,

Just got a message up to say brake lining wear see sercive centre - or words to that effect. Does anyone know how I can find out which require replcing, sort of taking each wheel off.

cheers

Ash
430 CLK '99

 

[anyweb]

most likely to be one or both of the front wheels brake pads or disc brakes.

the front brakes are approx 70% of your braking power, which is why i recommend looking at the front wheels, removing the wheels and having a visual inspection of the pads/brake discs is highly recommended and not difficult at all

heres how i worked on mine

http://anyweb.kicks-ass.net/personal/me/mycar/newcar/brake_discs/

cheers
anyweb

 

[television]

Morning all,

Just got a message up to say brake lining wear see sercive centre - or words to that effect. Does anyone know how I can find out which require replcing, sort of taking each wheel off.

cheers

Ash
430 CLK '99

By turning the wheels on full lock you can see the front pads pads.

Malcolm

 

[ashwaads]

Thanks for the replies - checked what I can see through alloys and laying on the floor and both front and rear seem ok. This alarm has only come up twice and only whilst parked with the handbrake on. Could it be the handbrake shoes? Or even a dodgy sensor?

Ash

 

[anyweb]

i'm not aware of sensors on the handbrake brakepads, as before, i'd start removing wheels to find the offending brake pads that are worn (also check the brake discs for sign of wear)

cheers
anyweb

 

[clive williams]

i'm not aware of sensors on the handbrake brakepads, as before, i'd start removing wheels to find the offending brake pads that are worn (also check the brake discs for sign of wear)

cheers
anyweb

To find the offending worn pads there is no better way than removing the road wheels. One of the things to watch out for is badly worn discs. The ridge around the top of the disc can cut into the wear indicator cable causing the elecrical contact. If the pads all look alright you will have to remove the wear indicators one by one to see if they are worn or exposed. If it is a disc at fault check the thickness with a micrometer (calipers or ruler won't do). Replace both the discs on the axle if one is worn together with the pads. Replace all pads on the axle if its just pad wear but consider the discs as these days they tend to wear as fast as the pads. (My previous Audi wore pads and discs out at the same time, every time)

Clive

500E
E320CDIT210

 

[television]

To find the offending worn pads there is no better way than removing the road wheels. One of the things to watch out for is badly worn discs. The ridge around the top of the disc can cut into the wear indicator cable causing the elecrical contact. If the pads all look alright you will have to remove the wear indicators one by one to see if they are worn or exposed. If it is a disc at fault check the thickness with a micrometer (calipers or ruler won't do). Replace both the discs on the axle if one is worn together with the pads. Replace all pads on the axle if its just pad wear but consider the discs as these days they tend to wear as fast as the pads. (My previous Audi wore pads and discs out at the same time, every time)

Clive

500E
E320CDIT210

I have never seen in my life a lip on the disc that has worn through the cable as the cable is much thinner than the pin,by the time the wear got down this far the replace warning would have come up.new pads are approx 10mm the max you can go down to is 4mm ( I have a new and worn set in my hand right now).

Re wear on the disc a slightly harder pad will give less wear on the disc,but requires slightly higher preasure on the pedal. though this must alter the ratio front/ back. Since I have put the harder pads in the front of my SL320 and Volvo V70R the rear disc have cleaned themselves up in both cases. In the case of the Volvo I fitted new disc and pads front and rear at the same time and the wear on the disc is equal back and front. I changed the rear disc only because of rust.
Malcolm

 

[Bumper]

You will see the Culp irate as soon as you remove the pads with the wire attached it doesn’t cut into the wire itself but cats into the hard plastic bit that connects to the brake pad. The pads must be just about worn right down or you have an excessive lip on the brake disk itself.

 

[clive williams]

I have never seen in my life a lip on the disc that has worn through the cable as the cable is much thinner than the pin,by the time the wear got down this far the replace warning would have come up.new pads are approx 10mm the max you can go down to is 4mm ( I have a new and worn set in my hand right now).

Re wear on the disc a slightly harder pad will give less wear on the disc,but requires slightly higher preasure on the pedal. though this must alter the ratio front/ back. Since I have put the harder pads in the front of my SL320 and Volvo V70R the rear disc have cleaned themselves up in both cases. In the case of the Volvo I fitted new disc and pads front and rear at the same time and the wear on the disc is equal back and front. I changed the rear disc only because of rust.
Malcolm

Malcolm, I assure you that the lip on the front n/s disc on my 500E, which was within 0.2mm of the wear limit cut through the insulation on the wear indicator wire. The wear indicator portion itself was partially worn but had not exposed the contact. There was still a reasonable amount to go.

I disagree with your comment on harder pads and disc wear. If by harder pads you mean ones with a higher temp range my experience is that the harder pads, used normally for competition and 'fast road use' have a much more abrasive action on the disc, which is exacerbated by the higher temps they are used at to get even moderate braking. Harder (read higher temp pads) are normally only available from specialist motorsport suppliers although, I see that Euro Car Parts now offer EBC Green Stuff/Red Stuff pads, which are fast road/motorsport only pads. The new ceramic pads, that are becoming available now offer the same sort of performance as the higher temp pads but over a bigger temp range and are much kinder to the discs

Clive

500E
E320CDIT210

 

[television]

Malcolm, I assure you that the lip on the front n/s disc

I disagree with your comment on harder pads and disc wear. If by harder pads you mean ones with a higher temp range my experience is that the harder pads, used normally for competition and 'fast road use' have a much more abrasive action on the disc, which is exacerbated by the higher temps they are used at to get even moderate braking. Harder (read higher temp pads) are normally only available from specialist motorsport suppliers although, I see that Euro Car Parts now offer EBC Green Stuff/Red Stuff pads, which are fast road/motorsport only pads. The new ceramic pads, that are becoming available now offer the same sort of performance as the higher temp pads but over a bigger temp range and are much kinder to the discs

Clive

500E
E320CDIT210[/QUOTE
I did my basic engineering back in 1950 fundimentals have not changed, on two sliding surfaces the hard one always wears faster than the soft one.
In the days of king pins and bushes, the steel pin always wore out before the bronze bush.
When I rebuilt my 1928 Rolls Royce I had to make 14 new shackle pins, all of the bushes were as new. On dynamo's and motor's the armature shaft would wear more than the bush.
As I said in my thread I changed all disc and pads at the same time,with harder pads on the front.17k miles later I have no lip or wear on the front, but I do have a lip and wear on the back, and for the first 45k miles I had no wear on the back, just rust. The 30/70 ratio has not changed that much.though a little more preasure is required on the Volvo, the MB has not changed much

If you put a steel or cast iron rod in a lathe and apply sandpaper of say 80 grit and apply to the rod you will only get a few scratches,do the same with 320 paper and that will reduce the rod. engineer's always used emery cloth for metal work and that is as soft as butter.
I am quite happy to put up pictures of my disc's.

Malcolm

 

[clive williams]

I did my basic engineering back in 1950 fundimentals have not changed, on two sliding surfaces the hard one always wears faster than the soft one.
In the days of king pins and bushes, the steel pin always wore out before the bronze bush.
When I rebuilt my 1928 Rolls Royce I had to make 14 new shackle pins, all of the bushes were as new. On dynamo's and motor's the armature shaft would wear more than the bush.
As I said in my thread I changed all disc and pads at the same time,with harder pads on the front.17k miles later I have no lip or wear on the front, but I do have a lip and wear on the back, and for the first 45k miles I had no wear on the back, just rust. The 30/70 ratio has not changed that much.though a little more preasure is required on the Volvo, the MB has not changed much

If you put a steel or cast iron rod in a lathe and apply sandpaper of say 80 grit and apply to the rod you will only get a few scratches,do the same with 320 paper and that will reduce the rod. engineer's always used emery cloth for metal work and that is as soft as butter.
I am quite happy to put up pictures of my disc's.

Malcolm[/QUOTE]

I do not doubt your engineering rationale. The common misconception is that there is such a thing as a 'harder' pad. It is a pad of different composition invariably with a greater heat transfer capability and a tolerence to the heat which builds up when braking. Sintered pads commonly called hard by the racing fraternity include the addition of metals commonly copper to assist the conduction of heat. The old Ferodo DS11 pads has noticeable bits of copper and were known for their highly abrading action on the cast iron discs. Your comments about hard and soft metals in contact are therefore confirmed.

What pads did you fit? I can see an explanation for the differential in the wear rates of pads and discs on your Volvo as being the result of the front pads not coming up to a proper working temp and all the work being carried out by the rear pads, which then had the job of slowing a heavy car nearly on their own. I had this problem on my rally car when I used high temp front brakes and standard temp rears in an effort to get the handbrake to bite. As a result I used to go through rear brakes twice as fast as fronts, which is contrary to convention. To confim this check out the coefficients of friction/temp graphs on the published data by companies that deal in the full range of pads, such as EBC, Ferodo, Brembo, Mintex, etc.

Modern brake discs wear out quicker as a result of the reduction in the carbon content of the material and the change in the pad constituants in order to omit the asbestos originally used as a conductor/binder.

Clive

500E
E320CDIT210

 

[television]

I do not doubt your engineering rationale. The common misconception is that there is such a thing as a 'harder' pad. It is a pad of different composition invariably with a greater heat transfer capability and a tolerence to the heat which builds up when braking. Sintered pads commonly called hard by the racing fraternity include the addition of metals commonly copper to assist the conduction of heat. The old Ferodo DS11 pads has noticeable bits of copper and were known for their highly abrading action on the cast iron discs. Your comments about hard and soft metals in contact are therefore confirmed.

What pads did you fit? I can see an explanation for the differential in the wear rates of pads and discs on your Volvo as being the result of the front pads not coming up to a proper working temp and all the work being carried out by the rear pads, which then had the job of slowing a heavy car nearly on their own. I had this problem on my rally car when I used high temp front brakes and standard temp rears in an effort to get the handbrake to bite. As a result I used to go through rear brakes twice as fast as fronts, which is contrary to convention. To confim this check out the coefficients of friction/temp graphs on the published data by companies that deal in the full range of pads, such as EBC, Ferodo, Brembo, Mintex, etc.

Modern brake discs wear out quicker as a result of the reduction in the carbon content of the material and the change in the pad constituants in order to omit the asbestos originally used as a conductor/binder.

Clive

500E
E320CDIT210[/QUOTE]
Thank you very much Clive for your answer, I must admit That I have never studied brakes the way that you have, and I Have learnt something more.
Looking at the disc (front) today they do seem to have a glaze, and though I drive the car to the max at times, I never use the brakes that much and only ever had one hard stop, the result being that I do have very slight disc run out more noticable when the car is cold. On a fast run it is not there.

Now for the sad bit, I only changed the pads because the wheels got so dirty. Must have been two years ago, I read the Greenstuff blurb thought about for a while and bought the one for a fast heavy road car ( don't know the colour) I think the ones on the MB are red.

Thanks again for info.

Malcolm

 

[clive williams]

Thank you very much Clive for your answer, I must admit That I have never studied brakes the way that you have, and I Have learnt something more.
Looking at the disc (front) today they do seem to have a glaze, and though I drive the car to the max at times, I never use the brakes that much and only ever had one hard stop, the result being that I do have very slight disc run out more noticable when the car is cold. On a fast run it is not there.

Now for the sad bit, I only changed the pads because the wheels got so dirty. Must have been two years ago, I read the Greenstuff blurb thought about for a while and bought the one for a fast heavy road car ( don't know the colour) I think the ones on the MB are red.

Thanks again for info.

Malcolm[/QUOTE]

Malcolm thank you for the response. I too have been seduced by the Green Stuff stuff, as you for the claims of lower dust production but I have yet to succome as I'm waiting for the pads to wear. Given the cost of Green Stuff (Greenbacks?) and your comment about disc glazing I think I will give them a temporary miss. I would have gone the same route and fitted front first, waited for the rears to wear and then fitted the same rear. If yours are glazing then the imbalance front and rear is probably too great and if I do go with Green Stuff then I'll have to fit both ends out.
There was a time particularly with a manual car that I considered myself to be light on brakes and I stayed with standard pads for road use. However, having got to the point of fading brakes around the lanes here in the big cars that I now favour it might make sense. Either that or slow down.:-?
Clive

500E
E320CDIT210

 

[television]

]

Malcolm thank you for the response. I too have been seduced by the Green Stuff stuff, as you for the claims of lower dust production but I have yet to succome as I'm waiting for the pads to wear. Given the cost of Green Stuff (Greenbacks?) and your comment about disc glazing I think I will give them a temporary miss. I would have gone the same route and fitted front first, waited for the rears to wear and then fitted the same rear. If yours are glazing then the imbalance front and rear is probably too great and if I do go with Green Stuff then I'll have to fit both ends out.
There was a time particularly with a manual car that I considered myself to be light on brakes and I stayed with standard pads for road use. However, having got to the point of fading brakes around the lanes here in the big cars that I now favour it might make sense. Either that or slow down.:-?
Clive

500E
E320CDIT210[/QUOTE

Clive on my SL I have different pads to the Volvo, and the disc on the SL do not, or have not glazed, also I have found no difference in braking effort from the originals.
OK just been down to the workshop and found the box, they are the ceramic
Number DP31363C for CL,CLK,S,M and SL just looked at the disc again and they are far from being glazed, they are in fact as scored (lines,groves) as they always were.
Well you have made me happy I will change the Volvo pads over to these. I think that they cost around £120, but in my case I cant take it with me.

Thanks Malcolm

 

[garethc200k]

Great tread very interesting and informative
Cheers guys