Upgrade your brake pads! As both David Hendy and I can attest, after 30 minutes of hot-lapping Lime Rock, both of our cars experienced dramatic, completely unsettling brake failure. David actually went off track; I got lucky and stayed on.

Both David and I run OE pads; he runs stock front rotors, and I run Ate PowerDisks. Made no difference, and our brakes left us almost at the exact same time. Strangely enough, they came back at the same time too! However, my brakes are not nearly the same as they were, they're still pretty squishy.

I'm going to bleed my brakes tonight, and will post my results. I'm inclined to think that nothing will change, as the Ate Super Blue fluid is only a week old.

Just a word to the wise...

__________________
"If God had meant for us to walk, why did he give us feet that fit car pedals?" Sir Sterling Moss

Michael
2014 E63S Estate
2006 SLK55
1995 E500
1986 Porsche 944 turbo

Hello Michael,

Thanks for the insight. What pads are you going to try next timeout?

Can you give us an idea of when the brakes started to go and when they came back? Any warping of the rotors?

I think I'm going to pick up a set of Mintex C-tech pads, but I plan to call a guy at CarboTech before I pull the trigger.

As to when they went away, it was after 28-30 minutes of nutso driving on a road course not known for its kindness to braking systems. The brakes stayed very spongy for about 1/2 an hour; tried driving around at low speed to cool them down, but that had little or no effect. The brakes then came back all of a sudden, but the pedal still feels spongy.

I think I may have slightly warped one rotor-I feel a small pulsation going on. I'm planning to have the front rotors cut, then go from there.

Hope this helps.

__________________
"If God had meant for us to walk, why did he give us feet that fit car pedals?" Sir Sterling Moss

Michael
2014 E63S Estate
2006 SLK55
1995 E500
1986 Porsche 944 turbo

I wouldn't bother "cutting" the warped rotors........
consider them,gone. Turning them will only make them thinner which is NOT what you want to do.

The less material you have, the less they can dissipate heat.

I have a few customers that like to run their "street" cars at PCA/etc types of events,(a97 500sl, & a couple of 911s) and have helped them get their brake systems working better.
Here are some of the things I have done for them.

Call Larry at carbotech and get some "REAL" brake pads,,,, my #1 choice is the HAWK BLUE compound
some MBZ pieces are not available "off the shelf" so you may have to send cores in to be made into comp pads.
(I have to do this with the pads for my 16v SCCA car)

Use a dedicated set of rotors for your comp pads!
Don't just swap your street pads for the comp ones because the comp pads will wear out real fast. The street pads leave a sort of residue "imbedded" in the rotors and it will chew up a set of comp pads in no time.
(note- I have been using the ATE powerslot fronts for two seasons and they wear much more "evenly" than stock ones)

Before every track weekend put your "track pads AND ROTORS on", fresh fluid (I use ATE superblue with no problems)
and most importantly GET SOME COOL AIR DIRECTED TOWARDS 'DEM BRAKES!!!!
Use cheap aluminum "slinky hose" dryer ducting, fancy scoops, whatever your heart desires, but you must have a way to get cool air to the CALIPERS/PADS.

Alot of guys make the mistake of ducting air to the rotors alone,,,,,,,,You need to keep the calipers cool- THAT is where the fluid & pads are!


Also your driving style will have alot to do with how good your brakes perform.
On the track, that brake pedal is like an on/off switch. Don't brake too lightly for too long.(this just heats up the brakes)
When you get to your brake point for a corner, get on 'em hard enough to slow the car down & set the nose down, then get your foot right back on the gas!


All of these things should help your pedal.

Are you using a set of comp tires on the track?
Using DOT stickies like Hoosiers/ TOYO Proxes RA1s etc will greatly improve your ability to corner, accellerate, AND BRAKE. The better the tire you use, the better your braking performance will be.
I hope this helps,,,,, sorry for the long post.

__________________
Alain
independant MBZ tech since 1981
http://www.motorsportlegendsks.com/

Is anyone aware of a good brake ducting kit for the 500E/E500?

It looks as if brake fluid temps where hovering near boil point for much of your 30 minute blast, maybe ducting could help?

On the bottom of the front end of 500e's there is an "access" door in each corner that hinges down.
These little plastic "doors" are there so you can easily get to the back of your foglamps in order to change bulbs.

You can remove the little doors and replace them with a 3 inch NACA duct that has a hose connected to it. You route the hose throught the inner fender panel, between the front spring & the chassis, over the tie rod assembly, and it will end right at the caliper.

If you look under your car, you will see this is a fairly easy project. The NACA ducts fit real nicely in the holes & need only to be held in place with a couple of screws.
Once you have the door removed the hose routing will be pretty straight forward. Just tie wrap the hose so it doesnt get smushed by anything, and tie wrap it on the tie rod assembly so it will "turn" along with the wheels.
The hose will last along time, but you should check it for holes/ damage when doing routine service.

I have tried to take pics of this in the past, but they are too dark.You should be able to get the ducts from Racerwholesale,Pegasus, etc and do the whole thing for around or less than a hundred bucks.

__________________
Alain
independant MBZ tech since 1981
http://www.motorsportlegendsks.com/

Alain-

Can you try taking a few shots? See if your camera has a "slow" setting, and hold real steady!

Thanks in advance

__________________
"If God had meant for us to walk, why did he give us feet that fit car pedals?" Sir Sterling Moss

Michael
2014 E63S Estate
2006 SLK55
1995 E500
1986 Porsche 944 turbo

Michael,
I lost my brakes on my Carrera track car last year. That WILL wake you up. My car is cursed with brakes that are too small for the car (just like my 500E). Cooling, pads & fluid type are critical (nothing new there). Try Performance Friction 93 or if you want unreal stopping power Pagid Orange (my favorite) You will hate them on the street unless you are fond of screeching metal sounds but boy will you stop at the track. With track tires & either of these pads, you are going to generate some serious heat and boil your fluid which is what happend to me & probably to you too. ATE blue is good fluid but on underbraked cars like ours, you need to bleed it the night before the event. The blue absorbs moisture too quick & it's wet boiling point is too low. It works fine on cars with big brakes as they don't generate the heat that we do. The big boys run Castrol SRF. I have gone to this & it is great stuff. It also has a great price ($ 70 a liter) but the wet boiling point is WAY up there & it basically doesn't absorb much moisture. In the long run, if your time is worth anything, you will save money running the SRF as you can easily go 6 months plus on a brake flush (they say 1 year plus but I think that's a bit much). Cooling air will help all this big time. Make sure to put the air either in the center of the rotor through the "eye" so the vanes in the rotor will carry the air from the middle out or as Alain said, on the calipers themselves. I am working on this now on the Porsche. Pulling the backing plates off helped some but you really need directed air.

Bottom line: My C2 widebody weighs 3014 Lbs. and has calipers on all four wheels the same as the fronts on our 500Es & it ain't enough. If you keep this up, you are going to want bigger brakes but the fixes will help. Since I started runnung the SRF, I haven't lost the brakes again. They will get a little mushy 15 min into a session but they hold up. Good Luck & keep the shiny side up!
Jay

Jay,

Since this thread started, I've decided to make some changes to my brakes, specificaly by upgrading to '94 E500 specs. I've purchased new front calipers & directional 320mm rotors, had the rotors slotted & cryotreated, and will run EBC Red Stuff front pads and Porterfield rear pads on the track. And Yes, I usually install new brake fluid within a day or two of tracking the car

__________________
"If God had meant for us to walk, why did he give us feet that fit car pedals?" Sir Sterling Moss

Michael
2014 E63S Estate
2006 SLK55
1995 E500
1986 Porsche 944 turbo

Michael,
Sounds like you have got it covered. I have been tempted to take the 500E to an event instead of the Porsche just to see how it does. Judging from your experience, it sounds like with fresh fluid & my stock brakes I could get 15 min. or so per run group of good track time before I started having issues. I might give it a shot this season just for grins. I would loved to see the look on some of my Porsche buddy's faces when my big 'ol Benz smokes a few of their butts.
Jay

If you can be easy on your brakes (for track conditions), a 500E does really well IMHO-well balanced, powerful, and with great brakes. However, clearly it's one heckuva heavy ride, and while the brakes are more than adequate for the street they have a tough time hauling down a 2-ton projectile repeatedly.

I've done 30 minute sessions, and when braking conservatively they held up fine.

So get out there!

__________________
"If God had meant for us to walk, why did he give us feet that fit car pedals?" Sir Sterling Moss

Michael
2014 E63S Estate
2006 SLK55
1995 E500
1986 Porsche 944 turbo

Our 93 500E has been to Buttonwillow and Willowsprings.

Stock brakes & pads did fine at Willowsprings (very little braking needed), however, at ButtonWillow definitely need more cooling (either ducts, or bigger discs, and better pads).

:-) neil
1988 360TE AMG
1993 500E

I took my E420 to the BMWCCA driving school last year and flogged car/brakes fairly hard - 1.7 mile track with ten turns. I have stainless brakelines, ATE Superblue fluid, stock rotors, and Mintex pads. It worked really well despite frying the brake pad wear sensors.

__________________
Charles Cleaver
1975 350SE + 1992 300CE-24 SportLine 5-speed + 2002 SLK320 6-speed + 1974 W114 280
1986 190E 2.3-16 (Decomm rear self-leveling suspension; Euro-code headlamps) sold
2004 Audi S4 6-spd - sold
1969 (2) and 1980 Porsche 911T, S, and SC - alas gone
1987 300SDL - Graf Spee; Euro-code headlamps; 16-inch 8-hole wheels - sold
1994 E420+(E500 suspension/E-code headlamps/PAD chip) sold
1968 250SE 4-speed (NICE car) - long gone
1962 220S 4-speed/column mount - long gone