Brake fluid

As those of you at rockingham know l had a problem with boiling my brake fluid.

Motal 5.1 is whats in the cars now and its only 9 months old so never thought id have a problem.

Looking on opie oils the motal 5.1 fluid has a:

Dry boiling point 270 °C / 518 °F

Wet boiling point 185 °C / 365 °F


So was thinking about trying this stuff (Motal RBF600)

Motul RBF600 Factory Line brake fluid is a 100% synthetic brake fluid particularly suitable for the demands of racing and for those requiring a high performance brake fluid.


This high performance DOT 4 brake fluid is particularly suitable for race applications and exceeds the DOT 5.1 and DOT 3 standards, except for viscosity at - 40°C (-40°F).


RBF 600 has extreme thermal resistance and stability. The very high boiling point (312°C / 593°F) of this brake fluid is better than conventional DOT 5.1 brake fluids and enables effective braking even under extreme conditions.


With its very high wet boiling point (216°C / 420°F), RBF 600 is also great in the rain. RBF600 is superior to conventional DOT 5.1 brake fluid (180°C / 356°F min) and DOT 4 (155°C / 311°F min) brake fluid.


RBF 600 brake fluid is suitable for all types of hydraulic actuated-brake and clutch systems requiring a non-silicone synthetic fluid. RBF600 is specially designed to resist the high temperature of racing brake (steel or carbon) and clutch systems


RBF 600 Factoryline brake fluid meets standards:



•FMVSS 116
•DOT 4
•SAE J 1703

100% synthetic brake fluid from polyglycol bases.


Very high dry boiling point of 312 °C / 593 °F
Very high wet boiling point 216 °C / 420 °F


I know certain types of fluid cant be used in road cars but im guessing that stuff will be ok? My car has no ABS btw.

Yeah the rbf600 will be fine mate. I thought about getting it but not cheap. I have castrol super dot 4 and specs aren't a lot higher than your motul 5.1...somehow though I didn't have any boiling fluid at the whole day at llandow?!

Two of the corners in particular were extremely heavily braked.

I remember reading somewhere that the theory behind dry and wet points was flawed... can't remember where though!

TBH Ad i'm not 100% that it was boiled fluid due to the lack of bubbles in the bottle... i genuinly think you had fade down to the overheated rears!

Seriously look into removing the stone guards and some air ducting... iirc (going back to my scrapyard days) the Peugeot Boxer / Citroen Dispatch had an air intake under the bumper tha you could use just infront of the rear arch to push some more air into it!

hard btaking from at least 120 mate, it was fade. I had no fluid issues. Are the discs man enough for the pads you're using?

I would be looking at pads tbh as said above. Discs are normally ok on most public trackdays but pad choice will make a big difference. A lot of the guys with preludes just use blueprint discs but go for decent pads and don't have problems!? What pads are you running front and rear?

Adam, I was using Motul RBF660 and didn't have any issues. Granted it's a completely different vehicle. Before the hairpin at the end of the oval I was at about 110mph.

He's running Carbotech pads front and rear - frankly there is no better pad!

I've put the fade down to the standard discs just getting too hot!

Yeh as stu said the pads wont be the weak point. Also in the mr2 champ cars they use carbotech pads with standard discs.

Thanks for the advise guys ill order some of that fluid anyway knowing its ok and look at removing the rear stone guards. Front guards have fins on them ducting cold air onto the discs so ill leave them on.

Also that fluid is currently on offer at opi oils lol

Could well be the discs then. What can you do about that though, as drilled discs are prone to cracking and a lot of debate on how much more effective grooved discs are.

I bet the designs of the vents between the layers vary... cheap discs are probably the same vents on a 320mm disc and a 220mm disc!

Adam, the front's weren't as hot as the rears... i could hold the nuts on the front!

bigger discs, bigger callipers, bigger pads. Rendering the debate redundant :p

I would have thought though if it was disc related my pedal would go hard. But my pedal went soft and to the floor but the brakes still worked?

I'm certain it's something to do with the CV grease going onto that disc, surely that being burnt off would have created some extra heat somewhere?

you might want to consider getting some brembo max rather than OEM. I got a pair of blanks for the front of mine for £57 delivered direct from Brembo.

http://www.dba.com.au/

We fit Dba's as an upgrade from standard discs, but without going for a big brake convertion. Great discs to be honest and what i have going on my car without a doubt!

Oh, and usually the street spec slotted ones. They are designed for towing generally, basically where extreme heat is produced so work well with hard driving!

At £330 a pair plus shipping and import tax they can GTF!

We dont buy them from that website buy them from a uk dealer, just sent that link for reference of what im talking about!

Brakes - You get what you pay for!

So what makes them different to a Mintex Disc @ £42

I can only talk about cars i know inside out... and i know what works on some cars (ie gto's, skylines etc). Minitex discs may stop some cars fine, but i know the minitex discs on a heavy performance car dont last like they should.

You got braided brake lines? Might have it written somewhere but tired and didnt see

Nah ive not mate think l should get some?

Without a doubt. Your changing the fluid anyway so stick them on then. Will prevent the spongy feel when they get hot. The reason behind that is because the standard rubber flexi's expand more as they get hotter.

Many options out there... ie exact engineering (i had custom ones made for the xsara), goodridge, hel (Sam has these on the prelude), black diamond use to make them - not sure if they still do?

Go for ones with stainless fittings if possible tho as much nicer if you ever need to undo them again!

As said if you're doing fluid anyway get some braided lines as makes a hell of a difference!

You lot are exspensive lol

Haha well if i was you i would first change my brake lines for braided and change the fluid. This will help your braking no end. Give it a hard drive on the road and you'll know how we mean.

If you still have massive problems with your brakes i would suggest looking into upgraded discs, or if gt4 brakes or alike are bigger and if they will fit?

Get those sh**ty old rubber things off tho!

lol ill be ordering these

http://www.roguesystems.co.uk/forms/Product.aspx?ID=495

Along with these tomorrow

http://www.roguesystems.co.uk/forms/Product.aspx?ID=426

Motal RBF660 is already on order.

Expensive few days this lol

Hold your horses. You thought about hel brake lines? Camskill do them for the mr2 with stainless fittings for 51 squiddies. This is where i got mine from!

LINKY

I thought those HEL ones had got a rep for splitting and seeping from the point where the hose meets the union, there's a big thread about them on one of the ITR forums. Certainly the ones on my 106 have barely been used and they already look knackered. Wouldn't buy them again.

The finding was of a few people that had split hoses at the unions was due to bad fitting. The hoses were left to tight by people and that put strain on them and subsequently split. Was a massive scare mongering tactic imo as I have heard of lots of peoples goodrich's splitting in the same way from bad fitting! Also got to remember with braided lines about being very careful with fitting and hose length as braided lines are made for standard height, not lowered cars unless custom made!

nellers2001 wrote:

Hold your horses. You thought about hel brake lines? Camskill do them for the mr2 with stainless fittings for 51 squiddies. This is where i got mine from!

LINKY

Yeh had a search on the mr2 forums the reason ive gone with the above is they have the bracket that bolts to the chassis as part of the hose. I could probably try and make something but id rather spend that bit extra knowing its done properly tbh.

Thanks for looking though mate

Fair point mate!! No probs!

+ you can get them in "sexy blue" lol

Worth every penny

Keep us all updated with differences with regard to how the car feels once fitted