Brake Squeal, after track event Options

[srb7f]

So I finally made it to my first track event with the 914 last week. A driver's ed, with my dad and his Honda S2000. Anyhow, I had an absolute blast, but hit the brakes harder than usual.

The front brakes are now squealing just as I apply the brakes. It goes away with more firm pressure on the brakes. They still work fine, but the squeal is like nails on the chalkboard.

I took the wheels off quickly over the weekend, took the pads out (there's plenty left), cleaned the dust off, and put things back together with no improvement at all. Calipers bolts are nice and tight. I do have the 320i brakes on the car.

I did notice that the pistons seem to have spun around a bit in their bores. I don't have any of the metal shims like the 914 front calipers have, and frankly I'm not sure that I'm even supposed to. I've had these brakes on the car for years, without problems until now. Would this cause squealing?

I think this weekend I'll also check the play in the front bearings and tighten as needed. Would this cause it?

Is there anything else I should check or do? Also, if all of this fails, I know there's a bunch of anti-squeal sprays, pads, etc. Which of these (if any) actually work?

Thanks, in advance,


Steve

[SirAndy]

The front brakes are now squealing just as I apply the brakes.

The heat could have glazed the pads.

Some competition pads squeal when cold until you get some heat in them.
My porterfield pads do that and i got used to it after a while. Just hit the brakes harder!
(IMG:style_emoticons/default/biggrin.gif) Andy

[Eric_Shea]

I did notice that the pistons seem to have spun around a bit in their bores.

Pretty much impossible for them to spin but, being placed improperly can cause this. Without the piston notch (read: 914 rears) the pads used to be beveled. This is why we're stuck with two pin diameters on a 914 rear.

Best to have the notches in the proper location so the pad meets the rotors at the proper angle.

I think this weekend I'll also check the play in the front bearings and tighten as needed. Would this cause it?

It can.

Basics: Organic pads can squeal but they stop better than metallics. You could have glazed them at the track. Make sure your bearings are tight, pistons are right and all of the pins allow the pads to move freely.

[ME733]

(IMG:style_emoticons/default/popcorn[1].gif) I.M.H.O...SIR ANDY is correct. your brake pads are glazed over...this can occur to street pads which have been heated, (roasted) YOU MIGHT be able to salvage the pads you have. The glazed surface of the pads is probably not too deep (THE ROSTED TOP PART of the pad.) get some very rough sand paper..(and some medium grit sandpaper ).and a very flat surface....and with some elbo grease...you can sand off the glazed , burned , rosted, top surface of the pad..down to the good part..detail finish with the medium grit..you will be able to see the difference. It,s not always easy to get the perfect street pad AND pads suitable for high speed events..(THIS POST REVISED AS I FORGOT THIS )..)....AND.....what I used to do is ...use a drill, with a FINE wire steel brush in the direction of rotor travel ...(as opposed to crossways) to clean up the ROTOR. Some pad material usually transfers into the rotor. Here is the good part. O.E.M. german steel rotors are the best you will ever find. Heat cycled as they probably are 1000,s of times they are not going to be prone to warping.(distortion)...Bleed the brakes while you are right there...after overheating the PADS. and maybe the calipers..you can occasionally accumulate WATER(condensation/air bubbles). Doing a Through check of your brake system AFTER ANY HIGH SPEED EVENT AS YOU are doing is a very smart thing.

[srb7f]

Always good to know that I'm not the first one this has happened to. They are metallic pads (Mintex I believe) and certainly were not designed for what I was doing.

Looks like I've got some work to do this weekend!

Thanks guys!

[Eric_Shea]

They are metallic pads (Mintex I believe) and certainly were not designed for what I was doing.

Ahhhh... those are glazed then for sure. No great loss. Someones way of telling you to get real pads. Those are one of my favorite pads to hate. I wouldn't get out the sandpaper... I'd get out the credit card.

This is why everyone loves the Porterfields in the R4S (street) compound. Good for street, autocross and high speed events, especially for 914's.

[SirAndy]

This is why everyone loves the Porterfields in the R4S (street) compound. Good for street, autocross and high speed events, especially for 914's.

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[srb7f]

Eric: Do you stock the porterfield pads for 320i front calipers? How much?

[Eric_Shea]

We generally have those in stock (same as the Brembo M-Caliper upgrade). They are $69.95 I can probably ship them for around $5.00 if you don't mind them broken down for a small Flat Rate box.

[Justinp71]

This is why everyone loves the Porterfields in the R4S (street) compound. Good for street, autocross and high speed events, especially for 914's.

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I actually had a bigger 951 caliper setup on my car with pbr ceramic pads, took them off to install my m-calipers with the r4s pads that I already had. The r4s pad seem to have alot more 'bite' and slowed the car down quicker even though the pad is like half the size.