Suwipin

Hi all,

This might be a stupid question but as I am practicing my heel and toe, I noticed that my brake vibrates a bit when I am braking hard (in order to heel and toe).

I'm wondering if this is due to the ABS or something else.

Oh and I'm having my brake fluid flushed next week to get ready for my 4th DE

Thanx in advance guys

Ray Calvo

if you feel actual vibration and don't hear the ABS chattering, it's the brakes I feel. Likely a warped rotor from my experience.

Suwipin

ouchhh I was hoping that it will not be a warped rotor

I've been using my stock brake pads and rotors for 3 DEs and I think I might be braking harder on my last DE (which was at Laguna Seca - hard on brakes). And I always remember NOT to use the hand brake after coming out of the track to avoid warping the rotors.

Ray, do you think it's normal to warp the rotors in 3 driving events?

My goodness, this hobby is not cheap <img src="graemlins/c.gif" border="0" alt="[ouch]" />

Jeff 993TT

[quote]Originally posted by Suwipin:
<strong>My goodness, this hobby is not cheap <img src="graemlins/c.gif" border="0" alt="[ouch]" /> </strong><hr></blockquote>

DOH!!!! I feel your pain too..

Jeff

Ray Calvo

[quote]Ray, do you think it's normal to warp the rotors in 3 driving events?<hr></blockquote>

You can do it on your first day during your first driving session - just come into the pits after a hot lap then hold the car stationary with the brakes. Creates a local hot spot that'll warp them for sure (and guess how I know!).

Classroom instructors at our events make sure they warn students of this.

JohnM

I recall a recent post that suggested warped rotors were pretty rare, but uneven deposition of pad material on the discs commonly occurs under the circumstances Ray mentioned - take a look at this article on the Stoptech site for their take on this: <a href="http://www.stoptech.com/whitepapers/warped_rotors_myth.htm" target="_blank">The warped brake disc and other myths of the braking system</a>

TomF

John,

Thank you for the link to this very informative article. Living here in the rainy Seattle area, brakes are subjected to all manner of heating and cooling. I have been battling the "myth" of the warped discs for years.

I have had a set of rotors resurfaced, installed new pads, and properly broken them in, only to have the disc "warp" out on me in a couple of months. After reading this, I am convinced that the combination of my driving style, (which by European standards is very conservative) and the constant wet stop/go traffic driving that we have here is the culprit.

Resurfacing the rotors is probably not removing all the cementite inclusions, and shortly, the judder appears again.

This article is the first compelling explanation about what has been occurring with the brakes on my cars over the last twenty years.

Thanks so much!

Cheers! <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

SundayDriver

I have to go along with the article. I always thought that rotors warped until I read that, some time ago, and thought about something that happened to me.

Before a track event at the Glen, my rotors "warped". This was on the way to the track, low speeds, light rain, not enough brake usage to get anything hot. What had happened is that I changed pads just before the event (from Pagids to OEM). There is no way this was warped rotors. At the track, I drove though it, gradually heating the brakes and then hard use. It cleared up, but came back from time to time.

So, first question - did you recently change pads (especially pad material type)? I would try a bedding process. Take the car on the highway and bed the rotors - here is the procedure I use - Drive at moderate RPM (~4000) in whatever gear you want. Ride the brakes with medium pressure using left foot. Give car enough throttle to maintain RPMs for ~15 seconds. Release brakes and cruise for ~15 seconds. Repeat ~6 cycles. Let cool with highway driving for a few minutes then do a pad bedding. 70-10 mph hard brakes, back to 70 and repeat ~6 times. Let brakes completely cool after this. This has often worked for me to get things settled down.

Mike in Chi

Hi Pin

One other thing to keep in mind for DEs or racing.

As you brake from high speeds, you want to have your maximum pedal effort initially and then back off. Not lighter, then squeeze it on. Otherwise you create excesssive heat, and risk boiling the fluid or warping the rotor.

And like Ray, guess how I know...

[quote] My goodness, this hobby is not cheap <hr></blockquote>

It was once pointed out to me that brakes, just like tires, batteries and gasoline, are consumables.

Hopefully that eases the pain just a bit.

M in C

JohnM

Glad to be of help, Tom, even if only indirectly.

To paraphrase Amazon, those who have found this thread interesting might also like to take a look at a similar thread on the racing forum: <a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=10&t=000389" target="_blank">Warped Rotor?</a>

Suwipin

John, Mark, and Mike: thank you for your input, I really appreciate it

John, I've seen that article before but I haven't really read it yet, I guess I will have to read it today Thank you John.

Mark, ever since I bought the car, I haven't changed the brake pads yet. Now that you brought up that point, it is possible that I'm running out of pads. I think I will go and check if my pads are okay. Thank you also for the instruction on the bedding process, I will note your instruction down and I'll remember to do it when I change my pads.

Mike, thank you for the tips on how to brake on DEs. I'll remember that next weekend when I go for my next DE

On another note, I just got back from a tour at Bruce Canepa Design which was organized by our local PCA group. Thanx Kim for forwarding the invitation to me and Jeff.

Here are some picture from the tour:

<a href="http://hobbystage.net/porsche/suwipin/1021152081-000574.html" target="_blank">http://hobbystage.net/porsche/suwipin/1021152081-000574.html</a>

<a href="http://hobbystage.net/porsche/suwipin/1021152132-000575.html" target="_blank">http://hobbystage.net/porsche/suwipin/1021152132-000575.html</a>

<a href="http://hobbystage.net/porsche/suwipin/1021152168-000576.html" target="_blank">http://hobbystage.net/porsche/suwipin/1021152168-000576.html</a>

There's Bruce in the following picture:

<a href="http://hobbystage.net/porsche/suwipin/1021152228-000577.html" target="_blank">http://hobbystage.net/porsche/suwipin/1021152228-000577.html</a>

Suwipin

Some more pictures if that's okay with you guys

<a href="http://hobbystage.net/porsche/suwipin/1021153122-000584.html" target="_blank">http://hobbystage.net/porsche/suwipin/1021153122-000584.html</a>

<a href="http://hobbystage.net/porsche/suwipin/1021153065-000583.html" target="_blank">http://hobbystage.net/porsche/suwipin/1021153065-000583.html</a>

Here's the engine of a 959:

<a href="http://hobbystage.net/porsche/suwipin/1021152996-000582.html" target="_blank">http://hobbystage.net/porsche/suwipin/1021152996-000582.html</a>

A Bugatti:

<a href="http://hobbystage.net/porsche/suwipin/1021152961-000581.html" target="_blank">http://hobbystage.net/porsche/suwipin/1021152961-000581.html</a>

<a href="http://hobbystage.net/porsche/suwipin/1021152907-000580.html" target="_blank">http://hobbystage.net/porsche/suwipin/1021152907-000580.html</a>

<a href="http://hobbystage.net/porsche/suwipin/1021152865-000579.html" target="_blank">http://hobbystage.net/porsche/suwipin/1021152865-000579.html</a>

An the interior of a 959:

<a href="http://hobbystage.net/porsche/suwipin/1021152827-000578.html" target="_blank">http://hobbystage.net/porsche/suwipin/1021152827-000578.html</a>