Mike@Ikon Motorsport

I'll start out by saying if StopTech has already posted this information, I am sorry for the repost.

As many of you will remember, last month an AW member was notified by his dealer that the RBF600 Brake Fluid is incompatible with the master cylinder. I immediately notified StopTech and after they researched the issue and contacted Audi, they have decided not to use RBF600 Brake Fluid in the A4 and S4. Audi would not confirm the location of the magnesium, only that it is in the hydraulic path. This is not entirely convincing to me, however I will discontinue the sales of RBF600.

Many have used the RBF600 and at length. If you are currently running this fluid, I would not be alarmed as there have been no reports of failure that I am aware of. However, I would still recommend switching to Motul 5.1 or another brand.

<b>My customers will be receiving replacement Motul 5.1 fluid, and I will be emailing you shortly.</b>

If any of you have any questions feel free to email me. I will be looking into offering another brand of performance brake fluid such as Castrol SRF.

Tsle

Damn! First I have to stop using Superblue, then this... Argh! Thanks for the info.

A4NCAR

and that is what started all of this. But we soon found out from Motul that the DOT5.1 was fine and that their RBF600 was in fact not compatible with Mg.

Audi RSF1

I remember this discussion from earlier but want to clarify something. Is there something specific to Motul 5.1 that makes it acceptable for our systems although every other DOT 5.1 is unacceptable? I do seem to recall that the characteristics of the Motul 5.1 allowed it's for use in DOT 4 situations, but if anyone has the actual specifics, it would be greatly appreciated. Before I began using the RBF (no problems at all), I did some research with my service tech and the Performance forum, and the universal response I received was that you must not use 5.1, and that RBF was fine due to its DOT 4 specification (that and not to use Superblue). I do not plan on switching away from Motul, I just want to clarify that their 5.1 is acceptable for our braking systems (compared to other 5.1). Thanks for any insight.

A4NCAR

Motul DOT5.1 DOES NOT have silicone and is perfectly suited for our brake system.



<i>
<b>Motul DOT5.1</b>
Non-silicone based, long life and 100% synthetic, DOT 5.1 BRAKE FLUID conforms to the highest standards in brake fluid performance. DOT 5.1 is specially designed for Anti-Locking Brake Systems (ABS). With a high dry boiling point of
270°C and a high wet boiling point of 185°C,
DOT 5.1 delivers the best brake performance.


SPECIFICATIONS

Product DOT 5.1 BRAKE FLUID

Feature 100% synthetic, polyglycol-based. Specially designed for anti-locking brake system (ABS).

SAE/DOT Standard FMVSS 116, DOT 5.1, DOT 4, DOT 3 &amp;
SAE J1703

Specification --

Maker's Approval --

Compatibility All types of hydraulic actuated brakes and clutch systems (not to be used with silicon and mineral-based brake fluids).

</i>

Audi RSF1

my post I realized that I did refer to the "others" as 5.1 instead of 5. The silicone is def. a no-no. This is good info to know. Now it's time to go get the 5.1. Thanks again!

bhvrdr

RBF 600 does not have silicone either.

bhvrdr

with regards to our cars. I have problems understanding why a DOT 4 fluid that has always been fully compatible with our cars is all of the sudden harmful to magnesium. Do you have any more information on this? Motul 600 is a DOT 4 fluid that has better wet and dry boiling points than the DOT 5.1. I can't figure out what would make it harmful as it contains no silicone. Any ideas please? Thanks, Mike

Audi RSF1

From what I gather, this seems related to the B6 platform, yet has anyone confirmed (from Audi) that this magnesium issue is only related to the B6 as a major design change from the B5? In my research, I could not find any issues or discussion re: this with the B5. Please let me say that I do understand that several knowledgeable sources have given input on this, however it almost sounds as if the lack of confirmed info on this topic specifically re: the possible changes to our systems and what part of the makeup of the RBF causes this incompatablity has led to some confusion that may be causing the distress of those using a product that has worked flawlessly in the Audi community for many years. With that said, thanks to all of those who have researched this topic. Now if we could just make sense of it all......

Mike@Ikon Motorsport

IMO, the dealership that originally raised the flag to AoA saw the warning on the back of the RBF600 bottle and used it as an excuse for incompatibility.

Motul hasn't specifically stated what the incompatibility is. I think Darryl got in contact with Herve Blancourt and checked on their position. He was unable to give him any info on the incompatibility but did verify it.

I completely agree with you regarding the RBF600. It is a better performing fluid than the 5.1, and with the price point and boiling points it is a great product. The main advantage to the 5.1 is it's less hygroscopic properties.

Like I said, I have never seen a report of RBF600 causing failure.