Alex-r-1

Hi guys. I'll soon be installed Goodridge stainless steel brake lines on my 507. Tell please, what brake fluid you use?

BLKROKT

Castrol SRF

Clark Kent

- is some great stuff. Motul 600 if you want to come down a notch.

Jasonoff

Keep in mind the DOT 4+ fluid MB uses is low viscosity used for the SBC system.

RBF600, Castrol SRF etc are quit a bit higher viscosity.

Curious if there's any adverse affects. I've been using Motul 5.1 since it's close to the DOT4+ viscosity.

Diabolis

The MB 331.0 DOT 4+ brake fluid is among the best on the market (the dry and wet boiling points are about the same as DOT 5) but it's nowhere near as hygrosocopic as other DOT 4+ glycol-based fluids so you can change it every two years instead of every six months.

As Jasonoff pointed out, the biggest issue here is the fluid viscosity. All DOT 4+ aftermerket fluids are about twice as thick as the MB stuff. I think the conventional SBC system was dropped in the late 2000s as MB now accomplishes the advantages of the SBC system using some clever programming in the ESP, but for proper operation of those you need the thinner fluid.

Yes, Castrol SRF is about as good as brake fluids get FOR TRACK USE ONLY, but unless you flush it every three months and never drive your car in the winter, I wouldn't use it in a daily driver car.

Silicone-based DOT 5 fluid is a big no-no in systems not designed for it as it will destroy pretty m,uch everythign, so if you're absolutely determiend to use something aftermarket, do what Jasonoff did and use the DOT 5.1 fluid... except that there's really no reason to use it over the OEM MB DOT 4+ fluid as their characteristics are the same and the OEM fluid won't bugger up your ABS pump, harden your seals or make the hard brake lines corrode from the inside.

If it ain't broke - or doesn't need upgrading as is clearly the case here - don't fix it.

AMG3.2

What are y'alls thoughts on ATE Type 200?

Diabolis

^ I used it interhchangeably with ATE SuperBlue (which BTW is now illegal for street use in the US because some idiot at the DOT decided that it can't be blue) - it's the same fluid and the Typ 200 and SuperBlue made for easy brake flushes as you knew you had the fresh fluid to each caliper when the color in the speedbleeder bottle changed... but as far as characteristics go, it's actually worse than the MB stuff. I now use the MB fluid in my street Porsche cars - the track beast gets SRF.

Alex-r-1

Diabolis, You recommend to use only the original brake fluid MB? Right! I drive my car only summer. The original brake fluid MB does not overheat?

Diabolis

Nope - I haven't managed to boil it yet under heavy track use (continuous ~1.5 hour sessions - basically a full tank of gas), at a fast track with heavy braking zones where you repeatedly hit 230+ km/h before you have to slam on the brakes to slow down to 80 km/h to make the next corner. I cooked my OEM brake pads, but the fluid was not an issue at all. The brake pedal didn't get even slightly spongy with fresh OEM MB fluid.

You do need to completely flush the brake fluid every two years even for street use (and at least once or twice a year if you're going to track it, and for good measure I always bleed a few CCs - an ounce or two - from each caliper after every track day in case there's any burnt or boiled fluid, but the last two times I went out the with the C63 I didn't see a single bubble, it was perfectly clear and didn't smell burnt at all, so even the little bit of fluid that was in the caliper itself took the heat with no ill effects).

As far as braking goes, IMHO the weakest link for track use are the OEM brake pads. They actually perform more than adequately even on the track, and I got only a *slight* amount of fade (maybe 5-10% at the most) after about ~15 laps or so (again, not fluid-related - the brake pedal feel was constant), but you will cook the pads and they will stink afterwards and have that 5-10% less bite for the rest of their life.

All of this assumes that you have the retrofit track cooling package installed of course, as your car will go into limp mode because of overheated oil *way* before you manage to get anywhere near the limit of the OEM brakes.

Jasonoff

How do you bleed? I've always pressure bled all my track and street vehicles.

I've heard you need to actuate the ABS module via star/xentury or something similar to get a proper bleed.

My pedal has always felt slightly spongy when the car is on and the brake booster is pressurized. I've also heard slowly pumping the pedal while pressure bleeding works as well.

AMG3.2

Interested in these questions as well^

BLKROKT

Don't need to activate the ABS. Use a pressure bleeder. Super easy. Most use the Motive Black Label (has the adapter to fit our reservoir):

Jasonoff

I use a motive. Have bled a few times now. Soft-ish pedal when it's running. Hard as f__k if it's not.

EDIT: I also modified mine to take in an air line.

Diabolis

Motive like the one above (mine has the black label though), and a Turner bottle with a check valve for the caliper end.

I also have one of these http://www.princessauto.com/en/detai...it/A-p8050832e which I use for my old P-cars, but you don't need one for the C63 (you're pushing the new fluid in with the Motive, not sucking it out with the vacuum pump).

Whatever you do, just make sure you use fresh brake fluid every time - that stuff is only good for a week or two at the most once you open the bottle or can.

P.S. Link to the Turner bottle: http://www.turnermotorsport.com/p-17...ple-bleed.aspx

Jasonoff - yes, when the engine is running and you press on the brake pedal hard, it will SLOWLY sink all the way down. Perfectly normal.

Jasonoff

What pressure do you bleed at?

EDIT: I'm not talking about the pedal sinking. My pedal is just softer than a friends. That initial squeeze has slightly more squish. I've bled brakes 8 million times without an issue. Maybe it's just a characteristic of my booster.

Diabolis

10 to 12 psi. Anything higher than that is too much for the ABS pump and won't bleed properly.

As for your soft pedal issue - that's your brake fluid viscosity at work. Fresh brake fluid in my C63 also results in a slightly softer brake pedal feel afterwards. The first time it happened, I went through an extra 2L of brake fluid bleeding all the calipers looking for that tiny pesky air bubble... but there wasn't one. Talked to the shop foreman at the dealership and he said it was expected - because of the freakin' low viscosity of the MB brake fluid, which increases over time as the fluid ages and absorbs moisture. I can still feel it after the winter fluid change before the first track day of the season (the ABS engaging over the winter months in the snow somehow accelerates moisture absorption). When I bleed it in the summer (like once a month, after every two track days) it isn't nearly as noticeable as the fluid doesn't absorb nearly as much moisture.

Jasonoff

Yeah I guess that would make sense.

looney100

So, does this use positive pressure to push the old fluid out when the bleeder valves are opened?

Diabolis

Correct.

svtkid

Do you absolutely have to use a pressure bleeder with our systems? If you actually use the two person method and depress the brake pedal while cracking a bleeder will it cause issues with the abs pump? Might be a dumb question, Im just new to over complicated vehicles.

Wobble64

Pressure bleeding is better. See this video for a detailed description on how it works and why it is better than the traditional 2 person method.
https://www.ecstuning.com/Mercedes_B...1/Video247-HD/

zcct04

Very good video - much more professional content than most of the DIY stuff out there.

AMG3.2

Hmm. This doesn't make MB fluid appealing at all to me. I'd rather not have to wait for the brake pedal feel to come back after some use...

Is there any other fluid I can use right off the bat that's equal to or better than OE fluid and will give me a firm pedal feel that I wouldn't have to wait for? Motul? Castrol?

Also, when you mention that right after the pedal feels soft, but gets better with time -- how much time are we talking? A month? A couple of days?

Alex-r-1

Please tell me, what sequence of pumping the brakes on my C63 507?

AMG3.2

Always the farthest wheel from the reservoir first. From there, work closer and closer.