Brakes Fading ...feel mushy when hot?

[Parkerfe]

My brakes would always start fading and feel mushy after a few laps at local track events. I have flushed out my brake fluid and replaced it with ATE Super Blue Racing Fluid and that problem has now disappeared. The ATE fluid has a boiling point 122 degrees higher than standard DOT 4 fluid which comes stock in the M5. Give it a try. It's an inexpensive way to improve the brakes on the M5.

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[DrKevM5]

Stainless Steel braided brake lines also improve modulation feel...also could use a pad upgrade for the track.

[ivory1]

I hear Castrol SRF is currently considered the highest performance brake fluid:
http://www.castrol.com/domino/casbst...CarsCastrolSRF

Some of the Porsche and Audi newsgroups have reported various problems with Super Blue, so be cautious. Here is one such thread:
http://www.audiworld.com/forum/m/racing/msgs/9462.phtml

[Jim Dolan]

ivory1, thanks for the DD evidence. I wouldn't think of changing my brake fluid without discussing it with the dealer, at the least.

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Jim
07/00 M5 Titanium over Red

[Teutonaddict]

Like Parkerfe, I ran into the pedal-to-the-floor experience after putting together a set of good laps at Road Atlanta this May. I bled the lines at the track and replaced with (Ford!) OEM fluid. [A BMW service advisor was kind enough to help in the process]

I'll be running Super Blue later this month, but also wanted to upgrade pads to a track-friendly compound: Have any of you had any luck with aftermarket brake pads for the E39 M5? Same goes for stainless lines. If so, what brands and sources have you found?

Thanks for your input.

[Parkerfe]

Originally posted by Teutonaddict:
Like Parkerfe, I ran into the pedal-to-the-floor experience after putting together a set of good laps at Road Atlanta this May. I bled the lines at the track and replaced with (Ford!) OEM fluid. [A BMW service advisor was kind enough to help in the process]

I'll be running Super Blue later this month, but also wanted to upgrade pads to a track-friendly compound: Have any of you had any luck with aftermarket brake pads for the E39 M5? Same goes for stainless lines. If so, what brands and sources have you found?

Thanks for your input.

The ATE Super Blue really works. I had my brake fluid flushed out and replaced with Blue at Bavarian Imports(404.351.2002) I am trying to obtain Pagid pads which are made in Germany.


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[daniel]

The fluid and pads are a great start. In my Viper GTS, the fluid made a good improvement, and I used Pagid on my Porsche 993... they had less fade, but were prone to serious noise (I recall a Pagid street/track pad like RS-4 or something). I recall that air deflectors worked well on the Viper... but don't know if they would fit well on M5.

Dan

[KKelly]

Super Blue works fine in BMWS. I have had it in my car for 1 1/2 years and eight track days.

You guys may be limited on pad choices but..if you contact companies like KVR they may make some for you or have some made. If they were sent a stock M5 pad for a pattern they could do it easily I believe.

I just switched in my E345 from Perf. Friction Z rated (okay, no fade but they wore fast when hot) to Cool Willy's from Turner Motorsport in the front. I am going to leave them on until my next event but plan on switching them out and running my Mintex on the street. I can change the fronts in less than 1/2 hour and 1 beer.

If you are going to track your 4000lb car regularly, learn to work on the brakes yourself. It is not that complicated and is in fact really easy. Either buy a pressure bleeder or install easy bleed nipples on your calipers so you can do quick brake bleeds. Even with Super Blue this is necessary.

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Kevin Kelly
91 M5
Dinan chip
Dinan Stage III
Racing Dynamics sway bars
18" BBS RC's
turbines for the track

[HadE55NowM5]

My '00 E39 had the movit/Porsche 993 Twin Turbo brakes for a while. I liked them somewhat; however, the pedal was a little too long and spongy for my tastes.

Just prior to selling my car, I removed this system as the new owner wasn't willing to pay a premium for these upgraded brakes.

For various reasons, I ended up getting the car back. But in the interim, I sold the brake kit to a "01 E39 M5 owner.

Not satisfied with the OEM brakes, I embarked on a different solution. In order to preserve the factory hydraulic ratio (i.e. the ratio between the total area of the pistons in the master cylinder in relation to the total area of the pistons in the brake calipers), this time around, I opted to retain the OEM calipers.

It seems that it is difficult, if not impossible, to source a larger master cylinder which contains pistons large enough so that the hydraulic ratio between them and the 44 mm and 36 mm pistons in the Porsche calipers remains close to stock. I believe that it was this alteration to my factory hydraulic ratio is what was responsible for the change in pedal feel and modulation that occurred with the Porsche calipers.

In order to optimize the factory brakes within the confines of preserving the factory hydraulics, I ordered European front and rear rotors.

These rotors differ from their U.S.-spec. in the following ways: they are floating front and rear, and the rear rotors have directional vanes. (Note: the rear rotors have a different part no. left to right). They cost about $250 each. The only negative side effect to floating rotors is there propensity to squeak and "drag" slightly more than their fixed counterparts. This can be heard by the driver when driving slowly with the windows down in an area with homes or buildings where the echo effect is apparent.

To further optimize things, I had these rotors cyrogenically treated.

The most important thing I did was get rid of the OEM brake pads. Short of Mintex, I couldn't find any company that made a replacement pad for the E39 M5. Finally, I found Carbotech in Fort Lauderdale, Florida.

Carbotech has a compound to die for!!! Not only does their material bite like a race pad, but they are super street-friendly. In the past, I have installed quasi-race pads on the street, but in every case I was very disappointed how they worked in the real world. Unless the driver put decent temperature in the brakes (i.e. got them hot), they simply wouldn't bite when cold. This plateau effect is particularly disconcerting if the driver needs to make an emergency stop without having used the brakes just before (i.e. an extreme lack of cold brake bite). This is something that inspires no confidence in the braking ability of the car.

Carbotech doesn't have E39 M5 brake pads on the shelf. Therefore, I had to persuade them to allow me to send them a set of E39 M5 "donor " brake pads so that they can remove the OEM brake pad material and install their own recipe!

Other than the fact that this compound dirties the wheels quickly and has a tendency to squeak more than the OEM brake pads, their astonishing stopping power is more than worth the trade-off!!! These pads simply transform the brakes of the M5, and the entire car itself!

I finished the brakes by having Carbotech source for me a set of stainless steel brake lines (I believe the E39 M5's OEM brake lines are the same as those on the 1996 - 2000 E39 528/540). I think that these brake lines are made by a company called Goodrich.

Finally, I used DOT 3 Ford steet brake fluid. This is an old racer's trick. When looking at the can, you won't believe what the wet boiling point of this stuff is (it's on par with that of racing brake fluid!). It's only about $3-4 per can, and doesn't have the adverse side effect of quickly absorbing moisture like racing brake fluid (something about the hydroscopic effect, etc.). That's why racers are constantly bleeding their brakes.

Sorry for the long explanation, but I thought that everybody on the board would like to know the results of my expensive experiment/science project.

I can't wait to see how the 4,000 lbs copes on the track. Last time I was at the track, it was with the OEM brake system, and I was not terribly impressed. Hopefully, the stopping distances and proclivity to fade will both be reduced.

If anyone needs the part nos. for the European rotors, please let me know.

[HadE55NowM5]

A couple points of clarification:

1) The brake lines are made by Goodridge (not Goddrich). (310) 533-1924.

2) The company that makes the brake pad material is CARBOTECH ENGINEERING (954) 493-9669.

3) The European floating two-piece rotors have aluminum hats (vs. steel hats on U.S.-spec. rotors which slightly reduces unsprung weight and aids with heat disipation). The theory behind these two-piece floating rotors is that they provide for better braking (especially under extreme braking) since they have a little bit of "give" to them. In other words, the brakes can find their own arc as more and more friction is being applied, resulting in truer, better braking.

[HadE55NowM5]

Spelling error! Should be "Goodrich," not "Goddrich."

Sorry, but I don't know how to use the edit feature!

[tomaselli]

Perhaps we should consider fitting these beauties!!!!!

www.movit.de/htm/m58.htm

[GradX]

Tomaselli, you've got it all wrong.

Here's what I am really going for--Big Yellow!
http://www.donrosencomp.com/porsche/...mic_brakes.htm

I can't wait for Movit to start selling these.