Squeaky brakes, even after new set- help

[bmwstuff]

Hi All,

Wonder if anyone can help, I had a problem with some rear squeaky brakes. It looked like the pads needed replacing so took them to garage and they said the squeak was becasue I needed new discs as they could feel a lip on them and was begining to rust.
After putting on the new pads and new discs, the same squeak! Really annoying as it happens only when am crawling in traffic.
Can anyone help? I read somewhere about the handbrake causing a squeak?

Another problem was that after they adjusted the handbrake the car sounded like it had a flat tyre for a few minutes (even the runflat indicator come on!), do you think this was the handbrake being adjusted too high? Anyway the sound went away.

Took these problems back to the garage and of course they said everything was fine and the "new" squeak was due to the new pads and discs!

Any thoughts appreciated!
Cheers.
Dan

 

[sp3ctre]

Try bedding in the pads properly... gimme a sec and I will dig out the procedure

Here you go: http://www.zeckhausen.com/bedding_in_brakes.htm

 

[chariszzzz]

what brake pads are u using?

 

[Curtis]

While having a lip on the edge of your disc is never a good thing it can never be the cause of a squeak, it just means that your pads are not sitting right to the edge of the disc and therefore that small area has not been worn down.

You can have issues where the handbrake mechanism within the disc rubs and causes a squeal, I had this problem on my car and it turned out that one of the springs that holds the handbrake shoes together was rubbing on the inside of the disc.

It sounds to me like they over adjusted the handbrake and the shoes have been gripping the braking surface while driving. This can cause that particular corner of the car to squat down as you drive off and give the impression of having a flat. It can build up excessive heat and cause damage within that disc and hub so be careful.

It's quite possible that the new discs/pads are squeeking, different compounds are more prone to it than others, what pads did you get? The Pagid RS29's I use on the track are a complete nightmare on the road, everyone stares at you as you approach a junction so I try to coast up and just dab the pedal at the last moment!! Anyway, I doubt you have RS29's but you could have a compound that causes similar problems.

You can usually eliminate the noise or at least reduce it by removing the pads and putting a light layer of copper grease on the back of the pads where they contact the caliper pistons and also the contact points between the pads and the areas where they seat into the caliper. Brake squeels are usually caused by high frequency vibration between the pad and the caliper and separating the two with this this layer of grease can make all the difference. For obvious reasons don't get any grease between the friction surfaces of the pads and discs!

 

[bmwstuff]

Hi Guys,

Thanks for all the quick reply, will try the bedding in process and look at copper greasing if it hasnt been done.
Pads are OEM equivelent, I have them on the front and they don't produce any squeal at all so it doesnt appear to be the cause.

If it's the handbrake, what's the best way to check this? Is it accesible by jacking up car or will I need to remove wheel and caliper etc?

Thanks in advance.
Dan

 

[Curtis]

You can only get to the handbrake mechanism if you remove the disc. To remove the disc you'll have to take off the wheel and caliper. The actual adjustment for the handbrake is done through a hole in the disc to a rotary adjuster inside but it's worth taking the disc off to check the condition of the components.