Horrendous Brake Squeal!

[laurieballard]

Hi

My wife has an E85 Z4 which we bought two years ago.

In that time I have replaced the front and rear pads and discs, plus I had to replace the front calipers as the piston would not retract properly.

The car has always squealed the brakes a tiny amount every now and then, especially in the summer but its got so bad now its embarrassing.

Its definitely coming from the rear so I re-greased the back of the pads, it stopped for a week then came back.

I replaced the fairly new Pagid pads with Brembo ones, greased the new ones and it seemed fine for a week or so but then came back.

The discs are pagid and are about 8 months old but it squealed before I replaced those, although probably not as bad.

Other than the calipers, I don't know what else could be causing it??

Im tempted to replace the rear discs again with Brembo ones but I feel this might be money down the drain. I can get two new calipers for like £120 and fit them myself.

Driving her mad as you can imagine due to the embarrassing noise, we are going to move the car on early next year but I would rather get it sorted.

Thanks

[PDJ]

Three things come to mind

The style of driving is quickly glaring the pads and they then squeal, the cure is to either remove the pads and rub them with some rough emery paper over a flat surface or go and drive the car and use the brakes as hard as you dare in a safe way.

The brake disc shields could be slightly loose or the mounting hole have rotted and it is loose, cure tighten up and or fit a penny washer over the hole to support the shield better.

Is the calliper free to slide on the pins, cure remove the pads and see if the calliper slides freely if not clean and grease pins and mounting holes re fit pads.

All the above is almost cost free.

[ph001]

You have to be driving like an absolute maniac to glaze the pads on the rear so that sounds extremely unlikely to me. The other point about making sure the caliper slides freely is good though.

A couple of ways you can usually sort this:

1) Add a thin shim behind the brake pad. https://www.amazon.co.uk/Brake-Anti-Squ ... text&psc=1
2) Try different brake pads.

Usually just changing the pad manufacturer is the easy answer - it just seems that some pads are much more prone to squealing than others.
You don't say which engine you have annoyingly, so unable to make any recommendations.

[Thrustyjust]

Make sure the edge of the pad that has contact first with the disc has a decent chamfer on the edge as this can cause squealing. Also if the discs are scored, that can also create noise.

[laurieballard]

Ok so I have basically had three different pads on it and they all squealed.

Original cheapo brand did it a little, then I swapped to Pagid and was fine for a week then started squealing. Now I have Brembo ones and again, fine for a week then squealing so I can't see how its the pads, glazing or otherwise, it has to be something else.

Will check the shields but as I say, its fine for a week after swapping the pads and then starts again!

I used Pagid discs so wondering if it could be these causing it?

Should have said but I greased the slider pins last time which made no difference.

Its either the Pagid discs or the callipers somehow.

Edit - My wife seems to think its worse once she has used them a bit, they are less squeally when the car is cold and gets worse once you have driven it a bit.

[Capa]

I've not heard of Pagid discs causing a problem before.

I have however had squeaky brakes due to disgustingly cheap discs before on another car, so it's not impossible. Given it's a common part you could perhaps try it. I'd be considering anti-squeal shims though as described above.

[laurieballard]

Anti squeal shims being the ones that come with the pads presumably?

All three sets came with like a metal backing plate which you could clip on or off.

I used this every time including now, unless there is something else you can buy?

[Jembo]

As a long shot, have you also checked the inner hand brake linings?

Arguably what u have done are the normal cures... good hunting

[laurieballard]

As a long shot, have you also checked the inner hand brake linings?

Arguably what u have done are the normal cures... good hunting

I have not actually, what would I be looking for?

Thanks

[ph001]

Anti squeal shims being the ones that come with the pads presumably?

All three sets came with like a metal backing plate which you could clip on or off.

I used this every time including now, unless there is something else you can buy?

Did you even read my post?

[laurieballard]

Anti squeal shims being the ones that come with the pads presumably?

All three sets came with like a metal backing plate which you could clip on or off.

I used this every time including now, unless there is something else you can buy?

Did you even read my post?

I did and saw the link but I was asking if these were in addition to the shims that come with pads these days or in replacement of?

We have a 2.0L, the noisy little 4 pot which makes more noise than power.

[MrPT]

A longer shot than some of the above, but are the anti rattle clips installed properly and are they still pretty stiff?

[Thrustyjust]

If you have changed a variety of pads , then perhaps give the disc surfaces a damn good emery cloth or sander going over and cross hatch the sand marks. Make sure that the slider points for the pads in the caliper is clean and not rusty. This works hand in hand with the greased up slider pins, but if rusty the pads wont back off when you take your foot off the pedal. If thats doesnt change anything, even from the off, then try some different discs .

[kis]

Most modern pads have the anti-squeal type pads already. So IMO will be something to do with the caliper or carrier...
Not heard of the rears seizing (normally the fronts) but are they okay? Pistons are releasing properly? The rubber boots are not torn?

Secondly the caliper and carriers eventually gunk up with dust, grease and dirt. Have you checked to see if the pads have free movement? The external pad should slide up and down the carrier bracket, and also the internal one that clips to the piston should slide up and down the caliper. So free movement, wire brush or small metal file to ensure its all freely moving. Then you grease these up to assist with the sliding

[laurieballard]

Ok so today I did the following

- Stripped both rear sides down, discs off etc.
- Cleaned both sides, all components using a wire brush and sandpaper.
- Greased slider pins
- Adjusted hand brake so it’s not fully up, basically adjusted it off a bit
- Copper greased back of pads again
- Ran some sand paper over the face of the pads

Took it out, still squealing!!! Made no difference at all.

It’s weird as if you touch the brakes it doesn’t do it and if you hard brake it doesn’t do it, it seems to be when coming to a stop if you hit traffic etc, like your not slamming on and not touching lightly.

I even bled them just in case.

We are looking to sell the car in a few months so I don’t wanna keep pouring money into it.

I’m convinced it has to be the callipers somehow.