987 Brakes squealing constantly... when not being used!

[PaulD86]

Hoping someone might be able to help here. My 987 Cayman R has brakes which squeal constantly. The hotter they are, the louder they get. But they stop making noise when you apply them. I know it's not uncommon for these brakes to squeal when used but my problem is the exact opposite!

An OPC de-glazed the pads and cleaned up the discs but that only helped for about 40 miles. Their line is the classic that the brakes can squeal and that audible issues aren't warranty which I'd accept if it was when used but when it's all the time it's extremely annoying as well as attracting attention from anyone you drive past with the racket.

Given what was done with the pads and discs made no difference I have a feeling it may be more like a caliper issue. There does seem to be a fair bit of drag from at least one as the car doesn't roll on slopes that my other car rolls immediately on. You also feel the drag when coming to a complete stop.

Has anyone experienced similar? I should add that the classic multiple high speed deceleration trick just makes things worse as it gets the brakes hot. I also thing it's the front OS brake only but not 100% sure as hard to say when driving. Oh and sometimes when the brakes are hot if you press the pedal when the car is stopped there is a fair bit of noise from the caliper.

Any thoughts welcomed. OPC just want to start changing bits it seems and I'd happily do pads and discs if I thought that would be a cure but from what has already been tried not working I have a feeling it won't be a long term fix...

[Slippydiff]

Time to get your jack out and see if you have a partially seized caliper. Jack each wheel up in turn and see if it spins freely. If not you'll find one of the pistons in the caliper has seized or the pads are binding in the caliper and not releasing when you release the brake pedal.

Edit to add you almost certainly have a seized/partially seized caliper. Jack the O/S/F up and try spinning the wheel, any excessive drag and you'll need to get the caliper overhauled (most likely as a result of split seal)

If you can have the car off the road and have another means of transport, these guys will sort it for you :

www.brakecaliperspecialists.uk/

(at a sensible cost that will mean you won't need a new caliper) And FFS don't take it to your local OPC, or open wallet surgery will ensue !!

Edited by Slippydiff on Friday 7th July 17:12

[PaulD86]

Thanks for the suggestion. I have a trolley jack so will jack the car and try that as a start. My daily car I work on and service myself but with the Porsche having extended warranty it's always gone to OPC for work - not where I'd go were it not for the warranty.

Have you personal experience of that firm? I was also suggested pro calipers in London who apparently specialise in Brembos. I wouldn't get them painted or anything, just a mechanical overhaul, but yes I suspect a a piston issue maybe.

[Slippydiff]

PaulD86 said:

Thanks for the suggestion. I have a trolley jack so will jack the car and try that as a start. My daily car I work on and service myself but with the Porsche having extended warranty it's always gone to OPC for work - not where I'd go were it not for the warranty.

Have you personal experience of that firm? I was also suggested pro calipers in London who apparently specialise in Brembos. I wouldn't get them painted or anything, just a mechanical overhaul, but yes I suspect a a piston issue maybe.

Yep, have used them 3 times now. A pair of 996 GT3 6 pots : Complete overhaul inc painting. Faultless. A set of 964 RS calipers : Complete overhaul inc painting. Faultless. A pair of BMW 335 calipers for pressure testing and painting. Slow, and they ended up doing them FOC either knowingly or unknowingly !

[worldwidewebs]

I'm pretty sure that the backing plate has come away from the pad.

Stuck to the back of the pads there is a metal plate with a couple of lugs which fit into the caliper - so when you release the brakes the pad is pulled away from the disc. If the pad is no longer stuck to the plate then when you release the brakes the pad is still rubbing the disc and so squeals. Easy enough to check.

Assuming that's what it is, you might get lucky and be able to re-stick the plate to the pad - if not you'll need new self-adhesive backing plates


Edited to add... I had exactly this on my Cayman R and the OPC couldn't find a problem. Mind you, they didn't take the wheels off to investigate it nor when they did the brake fluid change

[Buzzlt]

That's interesting had the same problem with my 987 so removed the pads and the stainless backplate from the back of the pad. I was under the impression that the stainless backplate was not supposed to be stuck to the pads so cleaned it put a little copper grease on (which is supposed to stop the squeeling). He presto no more problem. As far as I could work out the pads were only stuck to the stainless plate (with clips) with rust. I remember they weren't all stuck! Was I wrong to do this ?

[Slippydiff]

Buzzlt said:

That's interesting had the same problem with my 987 so removed the pads and the stainless backplate from the back of the pad. I was under the impression that the stainless backplate was not supposed to be stuck to the pads so cleaned it put a little copper grease on (which is supposed to stop the squeeling). He presto no more problem. As far as I could work out the pads were only stuck to the stainless plate (with clips) with rust. I remember they weren't all stuck! Was I wrong to do this ?

Hmmm, the backplate is actually a damper, hence the adhesive sticks the back of the pad to the damper plate, and the damper plate is located by the two round lugs that locate in the hollow recesses in the piston face. Those two lugs also act as harmonic dampers (at a guess) but by greasing the back of the pads you're damping the harmonic frequencies in a different manner (albeit in a way that mechanics have done for years) before the advent of the expensive and consumable (how convenient ...) harmonic dampers used by most manufacturers these days.

A lot of the trackday boys discard the damping plates because once they've been over heated, the adhesive doesn't work anyway.

But if the OP finds there's no obvious binding when he checks, there's every chance a damper plate has come adrift and is now wrongly located and giving rise to the squeal he's hearing.

[Rockster]

PaulD86 said:

Hoping someone might be able to help here. My 987 Cayman R has brakes which squeal constantly. The hotter they are, the louder they get. But they stop making noise when you apply them. I know it's not uncommon for these brakes to squeal when used but my problem is the exact opposite!

An OPC de-glazed the pads and cleaned up the discs but that only helped for about 40 miles. Their line is the classic that the brakes can squeal and that audible issues aren't warranty which I'd accept if it was when used but when it's all the time it's extremely annoying as well as attracting attention from anyone you drive past with the racket.

Given what was done with the pads and discs made no difference I have a feeling it may be more like a caliper issue. There does seem to be a fair bit of drag from at least one as the car doesn't roll on slopes that my other car rolls immediately on. You also feel the drag when coming to a complete stop.

Has anyone experienced similar? I should add that the classic multiple high speed deceleration trick just makes things worse as it gets the brakes hot. I also thing it's the front OS brake only but not 100% sure as hard to say when driving. Oh and sometimes when the brakes are hot if you press the pedal when the car is stopped there is a fair bit of noise from the caliper.

Any thoughts welcomed. OPC just want to start changing bits it seems and I'd happily do pads and discs if I thought that would be a cure but from what has already been tried not working I have a feeling it won't be a long term fix...

If being audible excluded a problem from being covered by warranty then a number of problems would be excluded.

There is likely a mechanical problem that accounts for the noise.

Others have suggested the dampener that at least in some cars I'm familiar with which sticks to the pad backing plate and has a metal basket that fits inside the piston might have "failed', has come unstuck.

However, I note in some cases, Porsche no longer lists the dampener on its parts list. For instance my 2002 Boxster. At some point Porsche removed the dampeners from the parts list and I don't know if they have remained off the list or have been put back on the list.

My Boxster (and to a lesser extent my 996 Turbo) manifest a bit of brake squeal and what I have found helps is to wash the brake hardware.

I visit a local DIY car wash and use the wand set to "rinse" to thoroughly rinse the brake hardware. I avoid jamming the wand nozzle tip down real close to the caliper for fear of the water pressure tearing the rubber dust boot.

With my cars and their iron brake rotors the water runs black with mostly brake dust. I give each brake a good rinsing then switch to the no spot rinse setting -- which sprays water at a considerably lower pressure -- and then visit each brake again and get the wand tip a bit closer to ensure all the dust is rinsed away.

Afterwards when I drive away from the car wash I always use the brakes immediately and enough to thoroughly dry the brakes. Do *not* park the car with wet brakes.

How this helps -- at least with my cars -- is the brakes generate a lot of dust. (Sure I'm stating the obvious but bear with me...)

While most of this dust gets on the wheel some of it settles on the piston dust boots and this load of dust can interfere with the natural tendency -- arising from the piston seals -- to cause the piston to retract slightly when the brake pedal is released. When the pistons retract the pads come away a small distance -- but is is an important small distance -- from the rotor. If the pads remain even in light contact with the rotor the brakes can develop a squeal when used, or even in severe cases when not in use with the car just going down the road.

With my cars I know it is time to wash the brakes when the brakes start to squeal when coming to a stop or when driving slowly through say a parking lot and I can hear the brakes emitting a faint squeal even though I'm not applying the brakes.

Washing the brakes won't help if your car's brakes require a pad dampener and one has failed or if there is a another problem. However, if the pads were de-glazed I would hope the tech would have taken note of a bad dampener or a bad pad and notified you.

Might add this brake dust problem can be exacerbated by driving in wet conditions for the brakes rust up when the car is parked and while the pads scrub away the rust the first time the brakes are used this rust adds to the dust problem. If the car is tracked over even just driven in a very spirited fashion often this can lead to an accelerated build up of dust.

[cd1957]

Hi I have had a couple of 987 with front caliper pistons sticking, this causes the pads to continually touch the disc, and either squeak or disc gets hot.I had them overhauled by a specialist in London, with 24hr turn around, and car perfect, with better pedal feel afterward.

With regards the post about the damping plates, they were designed to stick to the back of the pad, but the round ends are seizing in the pistons.I have replaced calipers under warranty when this first happening.

Chris

[PaulD86]

Sorry for the slow reply but thanks for the suggestions guys. This backing plate, would it be obvious if it has come away? The Opc had the pads out when they were trying to diagnose it so I'm wondering if it would have been visible to them at that time. And if this was the issue, would new pads fix it? They have a chunk of meat left but are definitely second hand but I'd be happy to replace them if I thought it might be a fix.

I haven't had a chance to check for binding yet but will over the next few days. Can't wait to get this fixed as it does seriously dent my enjoyment of the car.

[PaulD86]

Jacked the car up and there is definitely drag from the brakes and you can hear them pads on the discs as you rotate the wheel, however the mechanic from the small local garage was walking past and I asked him for a quick opinion and he didn't seem to think the drag was excessive. All I know it is is a lot more than either of the Mondeos I've owned or the Leon or Celica I've previously changed pads on. So I'm wondering where to go next - change of pads and dampers and see if that works (probably cheapest) and then if not send the calipers for an overhaul. Sound sensible?

[Slippydiff]

PaulD86 said:

Jacked the car up and there is definitely drag from the brakes and you can hear them pads on the discs as you rotate the wheel, however the mechanic from the small local garage was walking past and I asked him for a quick opinion and he didn't seem to think the drag was excessive. All I know it is is a lot more than either of the Mondeos I've owned or the Leon or Celica I've previously changed pads on. So I'm wondering where to go next - change of pads and dampers and see if that works (probably cheapest) and then if not send the calipers for an overhaul. Sound sensible?

If you're sufficiently mechanically able (that's not meant to be patronising btw) I'd remove the pads from the calliper you think is excessively "draggy" and using a long bar or screwdriver, lever the pistons back into the calliper one at a time. If one feels tighter (or won't move at all) you'll know where the problem lies.