Brake Fluid Change ND2 Motul RBF 660

Technical Area Wheels, Tyres & Brakes
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  1. My model of MX-5 is: 21’ ND2 2.0
  2. I’m based near: Shropshire
  3. I’m looking for technical help or recommendations on:

About to perform brake fluid change and plan to use Motul RBF 660 - After some research on the best approach to take, I came across the FlyinMiata guide from which I learnt the brake and clutch reservoir is shared - Will the car be OK with this fluid (still DOT 4) and is the general consensus to bleed the clutch using the gravity method for these cars to bleed the slave cylinder, is it enough when replacing the fluid?

Thanks!

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As long as you do not let the fluid level fall too far in the reservoir you do not need to worry about the clutch. Do the brakes first and get them OK. Then you can think about the clutch. The bleed system at the slave cylinder is not the normal bleed nipple as on the brakes so have a look here CLUTCH FLUID REPLACEMENT/AIR BLEEDING | 2016 ND Shop Manual before you start…
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Just as an added note, you are aware that the service interval for RBF 660 is 12 months so it will need to be replaced every year.
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Unless you have a track monster consider ATE Typ200, Dot4 high dry boiling point of 536 ⁰F.

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Ah the workshop manual really helps here, thanks!

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Not a track monster - More a weekend car and occasional track - The boiling points don’t look too dissimilar to the Motul RBF 660. Guessing under this use changing the fluid every two years is alright?

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I think that these high boiling point fluids take on water much quicker than the usual ‘road’ fluids so they need changing because of this and not ‘use’, so every year is ‘safer’.

Just out of interest why do you feel the need to go to one of these extreme fluids in a standard car?
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Based on recommendations essentially on the basis I plan to do the occasional track day - Brake pad and fluid upgrade has been the suggestions - Based on this EBC Yellow Stuff and Motul RBF 660 was top of the list as I didnt want to risk ruining the day with poor braking.

Still learning and would like to do more maintenance myself. Any recommendations?

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Yes with this fluid its change every 2 years

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In my Caterham days I used DOT5.1 as I did sprints and hill climbs where time was always an important consideration.

For ‘normal’ track day and road use the standard fluids should be adequate. It depends how committed you are to lap times and how much you want to ‘abuse’ your car. If you spend money on high end fluids (or high end anything for that matter) then you need to allocate the extra funds to maintain them.
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