W124 squeaking brakes

[telletubby]

Having two of these beasts currently and having had three others before them, I could say I'm fairly used to the W124. But almost without exception when lightly applied, my squeaking brakes are enough to turn heads. I've been told I need to apply them hard from time to time to 'rough them up' a bit. But when I do it doesn't seem to make much difference. Others have said this is because they're no longer allowed to use asbestos in brake pads.
Does anyone else suffer from this problem? Do other models? Is there a cure? Is it a question of trying a different pad manufacturer. In all other respects the brakes are in good order and function well.

 

[Bolide]

In my experience W124 brakes only squeal when you use non-Mercedes pads

Nick Froome
www.w124.co.uk

 

[brianbrian]

Hack saw a few thou down the middle of the pads and file the edges slightly you will find this will help.

 

[Bolide]

Hack saw a few thou down the middle of the pads and file the edges slightly you will find this will help.

This kind of behaviour is just not needed with proper parts

Nick Froome
www.w124.co.uk

 

[brianbrian]

I quite agree nick, but what alternative, throw these cheap pads away and buy decent ones, yes we would.

 

[teddycatkin]

We all learn from a lot from this forum--both Nick and Brian are dead right-- to stop it you will have to take them out anyway ?--ATE / Textar (originals) are not that expensive nowadays from Euro / GSF or other factors.
When you put them back use a liberal coat of coppergrease on the backs (make sure the discs are not too worn grooved or warped while doing the job too)

 

[Bolide]

Textar (originals) are not that expensive nowadays from Euro / GSF or other factors

I wouldn't use Textar pads - the second estate I bought had a set of rear pads put in when it was serviced. The brakes squealed in reverse. I told the garage to throw the pads away and use MB parts. The brakes stopped squealing. I've used MB parts ever since

The money you "save" by using pattern parts is soon frittered away in additional labour costs. And the originals work better. So why use anything else?

If you know these cars well it's easy to tell the difference between MB pads and aftermarket ones - one stop is all you need to feel the difference. W124s are very sensitive to things like this

Nick Froome
www.w124.co.uk

 

[telletubby]

Well my question is how come I've got squeaky pads after a service from my local MB dealership!

 

[teddycatkin]

Only one thing left---Must be that lousy weather you get down there then Telle!

 

[BlackC55]

ATE, and Textar make pads for MB.

I use ATE mainly as they make calipers for MB cars and I have never had an issue. Cheapo pads are normally made but other makers.

 

[Juddian]

Well my question is how come I've got squeaky pads after a service from my local MB dealership!

At a guess they've cleaned the brakes up with cleaning fluid removing any coppaslip in the process and the pads are vibrating against the caliper...my first thought would be remove and check them paying particular attention to see if the pad material is starting to detach from the backing.

Then reasemble using coppaslip as suggested above...i always give a slight wipe of slip to the edge of the backing plate where it contacts the caliper.

I've found Textar stamps and numbers on genuine MB pads though the genuine pads at least have the MB star....no such thing with the genuine BMW pads...absolutely identical to the Textar pads at well under half the price, not even a BMW stamp.

 

[teddycatkin]

Yes Black I have told them that--I prefer ATE myself --in our little workshop up here (servicing all makes) our local motor factor supplies ATE or Mintex--we have no come backs with either---I put Mintex on our 190 along with new discs 3 months ago--its done 2k since no problems (or squeaks)

 

[brianbrian]

Telletubby I am sure if you took your car back to M.B. where you had the pads fitted, they would do this free of charge,do you use your car on a daily basis if not this could be your problem as in wet damp weather it only takes a few days to get a film of rust on the disc, hope this helps.

 

[telletubby]

Well if the general view seems to be that they shouldn't squeak if they're genuine MB, I shall certainly be asking my dealer what pads they use!

 

[television]

The problem with squeaking is much more to do with the fitting than the brand, at the worst you may get a squeak for the first few hundred mile either in the forward or reverse mode.

It is caused be resonance from the surface of the disc, once the pad is suitably greased, it should hold the pad still. A few good hard stops often do the trick

 

[SilverSaloon]

proper merc pads are pretty cheap from MB dealer. not sure why pattern parts need to be used at all to be honest - maybe save £5 or £10 at best

 

[roadhog]

At a guess they've cleaned the brakes up with cleaning fluid removing any coppaslip in the process and the pads are vibrating against the caliper...my first thought would be remove and check them paying particular attention to see if the pad material is starting to detach from the backing.

Then reasemble using coppaslip as suggested above...i always give a slight wipe of slip to the edge of the backing plate where it contacts the caliper.

I've found Textar stamps and numbers on genuine MB pads though the genuine pads at least have the MB star....no such thing with the genuine BMW pads...absolutely identical to the Textar pads at well under half the price, not even a BMW stamp.

That bit made laugh, sorry. My first thought would be to take it back to MB!
Why on earth would you pay through the nose to have you car worked on by MB and then still have to check it yourself?

I fitted Eicher discs and pads to the rear of mine and they don't squeak at all. £39 all in and a couple of hours of my time. Job done.

 

[Number_Cruncher]

>>It is caused be resonance from the surface of the disc

The squeal IS the disc resonating - sometimes in more than one mode at a time.

The root cause of squeal, and the engineering of means to stop it in 100% of cases has eluded brake manufacturers and researchers for many years. In attempts to model and understand this behaviour, quite complex computer based mathematical models of the motion of the pad and disc were being built as long ago as the 60's.

Indeed, research has been active in UK Universities on this subject very recently (I'm not sure if the credit crunch and the lean times suffered be manufacturers has dried up the funding for this work)

In some cases, adapting the piston and pad to move the centre of pressure of contact towards the leading edge has helped - hence the step you sometimes see in the bearing face of caliper pistons.

Huge amounts of money have been spent by manufacturers and research councils and brake manufacturers, and, I'm sure that if the 100% cure-all was a dab of copperslip, that's how brakes would be supplied by the vehicle manufacturer.

The problem is so chaotic in nature that you can strip down a squealing brake, do nothing at all other than rebuild it, no grease or copperslip, and it *may* stop the squealing.

If the pads are in good condition, the pistons in the caliper are free, the sliding pins on the caliper are free, and the pad supports are in good condition, then, a squealing brake is causing no mechanical harm, and squealing brakes actually tend to be efficient brakes!

Original equipment pads do tend to be quieter than spurious aftermarket pads.

 

[television]

>>It is caused be resonance from the surface of the disc

The squeal IS the disc resonating - sometimes in more than one mode at a time.

The root cause of squeal, and the engineering of means to stop it in 100% of cases has eluded brake manufacturers and researchers for many years. In attempts to model and understand this behaviour, quite complex computer based mathematical models of the motion of the pad and disc were being built as long ago as the 60's.

Indeed, research has been active in UK Universities on this subject very recently (I'm not sure if the credit crunch and the lean times suffered be manufacturers has dried up the funding for this work)

In some cases, adapting the piston and pad to move the centre of pressure of contact towards the leading edge has helped - hence the step you sometimes see in the bearing face of caliper pistons.

Huge amounts of money have been spent by manufacturers and research councils and brake manufacturers, and, I'm sure that if the 100% cure-all was a dab of copperslip, that's how brakes would be supplied by the vehicle manufacturer.

The problem is so chaotic in nature that you can strip down a squealing brake, do nothing at all other than rebuild it, no grease or copperslip, and it *may* stop the squealing.

If the pads are in good condition, the pistons in the caliper are free, the sliding pins on the caliper are free, and the pad supports are in good condition, then, a squealing brake is causing no mechanical harm, and squealing brakes actually tend to be efficient brakes!

Original equipment pads do tend to be quieter than spurious aftermarket pads.

This is why as I said a few good hard stops often cure the squeak, the rear brakes only get 30 % of the braking pressure, so this allows the disc to sing away, with new pads and a few very hard stops it wears the surface of the new pad to that of the disc, often removing the squeal

 

[turbopete]

a tip for anyone changing pads, if the new pads have anti squeal shims, make sure theyre used, and give them a good coating of copperslip where the shim and the caliper meet, and also grease the pads where it slides in the caliper at the ends (obviously!)
If the new pads do not have and are not meant to have anti squeal shims, check the backing plate of the pads (opposite side to the friction material). if they are smooth ie just metal, grease in the same way you would with shimmed pads as described above. if the pads have no shims but are meant to, either remove them from old pads or buy replacements and proceed as above.
heres the tip though. if the pads have a textured, almost rubbery type of substance on the backing plate where they meet with the caliper, grease the END of the pads ONLY. this rubbery type substance is designed to make the pads "stick" to the caliper so that they cannot resonate and squeal! if you grease the backing on them, they will not stick and will almost certainly squeal! trust me, ive seen it happen a number of times now! apologies for my ramblings, but i hope this is of some use to someone!