UPDATE on MOTUL brake fluids...

[Jet Jockey]

I just called Motul France again and spoke to the tech rep. This write up is based on my talks with him. I am still waiting to hear from the Canadian rep.

This time I went further with him in the details and I we also talked about the 5.1 fluid.

OK I told him to pull out everything technical on their brake fluids and he got his book with what fluids are approved with which car manufacturers. I asked him to look up Audi then the A4 model.

I will include all the brake fluids made by Motul and all the norms and standards under which each and everyone of their fluids are certified. So read on.

First of all he tells me that when a norm is met, like the DOT 4 norm, corrosion testing is part of that norm.

Obviously since I'm in London, I don't have my owner's manual with me but IIRC, in our manual it says we can use DOT 3 and DOT 4 fluids, correct me if I'm wrong.

In any case his book and documentation say that Audi recommends up to DOT 4 and that their "regular" DOT 4 fluid meets those norms.
See the DOT 4 certification below.

Additionally since the RBF 600 falls under the DOT 4 certification or norm it is also approved. See the RBF 600 certification below.

Now when it comes to the 5.1 fluid it gets a bit more confusing. Now Audi does not recommend 5.1 brake fluid specifically in our manuals IIRC. Perhaps this is where the confusion comes from. Maybe the little robots at the dealers and the bigger ones at AOA don't realize this too, thus the "no the 5.1 is not acceptable" answer. Someone should call or e mail AOA and get their version on the Motul 5.1 brake fluid or any other brand of 5.1 brake fluid. In any case I believe the reason the 5.1 is not on Audi's list is simply because Audi did not test it yet or had not tested it when they wrote up the manuals.

Here is the kicker on the 5.1 fluid, it meets DOT 3 and DOT 4 norms so technically it too should be OK to use in our cars. See the 5.1 certification below.

To sum it all up, unless I get something in writing from Motul France or Motul Canada, you can safely use DOT 4, including the RBF 600 fluid in our cars. Technically the 5.1 meets DOT 3 and DOT 4 norms and should also be safe for use in our cars. It was specially designed for cars with ABS systems.

No where is there a written warning about magnesium being a problem with Motul brand brake fluids and this was collaborated in my talks with Motul France.

I hope this settles the issues but if someone knows something different,please let us know.

MOTUL brake fluids certification an norms:

RBF 600

100% synthetic fluid for hydraulic-actuated brake and clutch systems. Specifically designed to resist the high temperatures of actuated (steel or carbon) racing brakes and clutch systems.

EXTREME THERMAL RESISTANCE AND STABILITY: the elevated boiling point of RBF 600 FACTORY LINE (312°c / 593°F) enables effective braking even under the extreme conditions of competition.

VERY EFFICIENT WHEN RAINY: the very high wet boiling point (216°c / 420°F), is superior to conventional brake fluids provides a particularly efficient braking system in rain and put back the apparition of vapor lock.

NORMS : FMVSS 116 DOT 4 / SAE J 1703 / ISO 4925


DOT 5.1 brake fluid

LONG LIFE 100% synthetic fluid for hydraulic actuated-brake and clutch systems.
DOT 5.1 NON-SILICONE BASE.
Fluidity specially designed for anti-locking brake systems.

LONG LIFE FORMULA : the high wet boiling point (185°c/365°F), superior to DOT 4 and DOT 3 fluids enables to use this product longer.
SPECIALLY DESIGNED TO ANTI-LOCKING BRAKE SYSTEM (ABS) : its viscosity (820 centipoises at -40°c / -40°F) lower than DOT 4 and DOT 3 brake fluids, allows MOTUL BRAKE FLUID DOT 5.1 an easier fluid circulation in micro-valves of anti-locking systems.
PERFECTLY NEUTRAL WITH SEALS USED IN BRAKING SYSTEMS. ANTI-CORROSION.

STANDARDS : FMVSS 116 DOT 5.1 NON SILICONE BASE & DOT 4 & DOT 3
SAE J 1703


Dot 4 brake fluid

100% synthetic fluid for all types of hydraulic actuated-brake and clutch systems.
DOT 4.

HIGH THERMAL RESISTANCE AND STABILITY: the high boiling point (245°c / 473°F), superior to DOT 3 conventional fluids enables an effective brake even under extreme conditions.
SECURITY: the high wet boiling point (158°c / 316°F) superior to DOT 3 conventional fluids enables longer product use.
PERFECTLY NEUTRAL WITH SEALS USED IN BRAKING SYSTEMS. ANTI-CORROSIVE.

STANDARDS : FMVSS 116 DOT 4 & DOT 3 SAE J 1703

[cj-S4]

Personaly I like ATE Super Blue Dot4. Here's a good brake site,, on the fluids page they go into alot more discription of the fluids than most places. Just FYI,,

http://www.bestbrakes.com/brake_fluid.shtml

[Jet Jockey]

Thanks.

[CyberPMG]

Originally posted by cj-S4
Personaly I like ATE Super Blue Dot4. Here's a good brake site,, on the fluids page they go into alot more discription of the fluids than most places. Just FYI,,

http://www.bestbrakes.com/brake_fluid.shtml

I've heard from some other threads that people (Ikon Motorsport) have had failures and squeaky clutches when using SuperBlue.

With all the research done with Motul, I'm sticking with my RBF600.

[cj-S4]

Originally posted by CyberPMG
I've heard from some other threads that people (Ikon Motorsport) have had failures and squeaky clutches when using SuperBlue.

That could be attributed to alot of things other than type of fluid used. I like it because of the color, you always know when it is bled through. Not to mention the specs are quite good.

[neoprufrok]

Thanks Jet. Great information as always. I'm glad that I'll be using Motul 5.1 once my rear pads/rotors and SS lines are installed.

[A4NCAR]

Originally posted by cj-S4
Personaly I like ATE Super Blue Dot4. Here's a good brake site,, on the fluids page they go into alot more discription of the fluids than most places. Just FYI,,

http://www.bestbrakes.com/brake_fluid.shtml

From the number of people who have said to avoid ATE BF, I have followed their advice. I'd get Motul, or another brand. Here's my list;

Motul DOT 5.1
Motul RBF 600

Pentosin Super DOT4
Pentosin Racing

AP Racing 551 Brake Fluid

Castrol SRF

[A4NCAR]

Tell me something I don't know... Thanks for looking into it though.

This all started because of the DOT5.1 and a dealer saying it was not compatible. Then someone mentioned Magnesium in the brake system (which Audi supposedly confirmed). And there was also someone at Motul who informed someone here, that the RBF600 was incompatible with Mg., but the DOT5.1 was fine. So it's understandable how all this confusion came about. Obviously, the DOT5.1 is going to cause problems with a dealer/tech because it's not DOT3/DOT4 BF (although you only have to read the label to find out it is). But we know it is spec'd to work as those, as well as in a ABS brake system. I've never been worried about the DOT5.1 being incompatible. The only issues looming over this matter was the point of Magnesium being in the brake system and the RBF600 being incompatible because of that. The DOT5.1 was never really an issue except for it's name, "DOT5.1", which throws people off. And it is also not a DOT5 "silicone" BF, like many had thought.


I use, and will continue to use, Motul DOT5.1 BF.