Possible Explanations for Brake Squealing?

[Jameslovesporsches]

Hi everyone,

I was wondering what are some possible reasons for intermittent brake squealing. In my 98 Boxster with only around 4000 miles, the brake pads all look like new, but one of my rear brakes sometimes squeaks whenever I apply the brake. Is there something that could be loose? Or need to be lubricated? I'm pretty sure it's coming from the driver's side rear, but it only happens when I apply the brake. And for some reason, only at some times and not others. The sound is definitely noticeable, so please help!

James

[porscheneer]

A 98 with 4000 miles, thats impressive how do you keep from driving it?

Is the squeel present during light braking or even when you hit the brakes with substantial presure? How is your brake fluid level? any leaks?

I noticed your from Houston, whatever you do dont take it to Momentum Porsche, I have done some research and found some independant garages

J

Edited November 2, 2004 by porscheneer

[Jameslovesporsches]

A 98 with 4000 miles, thats impressive how do you keep from driving it?

Is the squeel present during light braking or even when you hit the breaks with substantial presure? How is your brake fluid level? any leaks?

I noticed your from Houston, whatever you do dont take it to Momentum Porsche, I have done some research and found some independant garages

J

<{POST_SNAPBACK}>

Haha, it's used too! I enjoy driving it soo much. I think the previous owner simply preferred his more sedan like cars. In Houston, which independent garages can you recommend? Thanks. I don't think brake fluid is low, but I'll check soon. By the way, the squealing is only audible at low speeds (slowing to a complete stop, for example). Any other suggestions?

James

Edited November 1, 2004 by Jameslovesporsches

[phrankandbeanz]

brakes might be dirty? Is your car dirty? Maybe the brake pad is misaligned and I doubt the pad is worn out.

[adsach]

When my Boxster was new, I heard the brakes squeal sometimes. Now I no longer hear them squeal, but passengers hear them. I am on my second set of pads front and rear.

As far as I know, Brembo high performance brakes just squeal, it's part of thier charm:)

[helix]

Hi

My my00 with only 15000 miles has original pads still and they squeal at times when showing to a stop ( especially the rears). My pad were is at about 50% now. I have read other strings discussing different pads / different amounts of noise so if they seem otherwise fine I wouldn't be to concerned.

[Tool Pants]

What transmission do you have in the car?

[Jameslovesporsches]

Tool Pants,

I have the 5 speed manual transmission.

James

[mrmickeymouse]

If your brakes are squealing, I have the easiest fix for you, a garden hose or power spray.

The majority of squealing is caused by a build up of brake dust and a simple cleaning [power water] on your brake calipers will provide cheap relief.

Upon doing it you will see a stream of black dust trickling away. After that you will either have a quieter brake system or a cleaner brake system which to inspect the brakes.

Try this and it may fix it. Carb cleaner will also do it, but water is better and cheaper, and much more plentiful.

Scott

[HenryV]

If your brakes are squealing, I have the easiest fix for you, a garden hose or power spray.

<{POST_SNAPBACK}>

Just don't drive afterwards with wet brakes :o

FWIW - this applies to stock pads - using them (brake hard) seems to remedy the squeel.

The inverse, not braking hard (easing in) seems to cause the squeel.

My $.02.

[porscheneer]

I agree, Power wash the brakes then do some hard braking to see if that does the trick. That would be the first course of action it will cost you 2 quarters at the power wash. You can get the brake parts cleaner or the carb spray, any non residue spray but you wont get as much pressure or flowrate as the pressure wash.

If that does not do it then as frank mentioned you would check for a mis alignment.

Tool pants,Im curious as to why the tranny comes into play?

[mrmickeymouse]

There really is nothing to align, you may [weird circumstance] have one piston weaker then the others, it would then apply a offset pressure.

What I have mentioned almost never happens.

Back to brake alignment:

The pads are given equal pressure on both sides [4 piston caliper] both pads have a backing plate which is given equal pressure to the pad.

There really is nothing beyond applying an anti squeak compound or anti squeak/ vibration dampers to fix it.

I have had so so luck with doing it after the fact of applying the new pads and then getting a squeak. I have had terrific luck with anti squeak compounds [High temp silicone] on already bedded brakes.

Even know Porsche say's it is a No No...

Scott

[Moose]

On my BMW three, I have single piston calipers. They are hollowed and the hollow end is open to the elements (faces the rear of the pad). Three squeal culprits reared their heads:

1. sympathetic vibration between the piston and the rear of the pad. Solution: synthetic brake caliper grease between the pad and the piston.

2. Too liberal with the brake caliper grease-- rocks and grit got suspended in the grease and sandwiched between the piston and the rear of the pad. Solution: clean off the goo and re-seat the pad.

3. Loose caliper bolts (scary)-- first sign of looseness was brake squeal with progressively worse squealling to give me (the knothead) the idea that anti-seize on the caliper bolts was probably the wrong idea. Solution: medium grade loctite and an impact wrench to torque the caliper bolts.

The squeal is back, but I know it is not hurting anything but my pride and my ears. I had the same problem on my 928 in the rear but, oddly, the blue caliper grease and a new set of rotors and pads when needed resolved the issue.

I suspect, even though the Boxster calipers are four piston on my standard box apply the pressure more evenly than the single pot calipers on my 323, that the sympathetic squeal can also result on our cars.

Hope this helps-- it's experience on a different car but seems like it would apply here too . . .

[vsapra]

I think Brake dust usually gives me the squeak - the brakes don't feel twitchy at all although.....I had light squeal from my rears on my '01S/6-sp with 33.5K miles. This was only obvious when slowing down at low speeds.

Yesterday - I made an emergency braking manouever - from 80mph to 0 in a very short distance - I had my right foot planted.....and ever since then, the squeak has gone away.

Although I don't do a lot of straight line breaking as described above - it was nice knowing that the S brakes are fantastic! :notworthy:

V.

[Tool Pants]

Tool pants,Im curious as to why the tranny comes into play?

<{POST_SNAPBACK}>

Cars with tips can glaze the pads and cause noise. But James has a manual transmission. Just a shot in the dark.

http://www.pca.org/tech/tech_qa_question.a...5-9B0C45401ABC}

http://www.pca.org/tech/tech_qa_question.a...C-8A65DE9ABEE3}

[Subanez]

Don't forget that a lot of high-performance brake systems actually have a "normal" squeal, because the compounds are harder than other brakes. A little noise coming from the pads does not necessarily mean that the pads are wearing or that there are any problems.

Of course, if the noise drives you nuts, feel free to clean the pads and try to get rid of it for a while. Its simply an inherent noise (from my experience).