Brake fluid

[Bounce]

Im due a brake fluid change,so thought id get some good stuff put in before the ring and spa,do you guys use castrol SRF which is on offer at the moment from Opie,athough still a lot more expensive than other race fluid,or is there another you use.;)

[shimmy]

AP do not recommned any silicon based fluid with AP kits (see AP details below)

SILICONE BRAKE FLUIDS – A WORD OF CAUTION
AP RACING NEITHER MARKETS SUCH FLUIDS NOR RECOMMENDS THEIR USE WITH OUR OWN OR ANY OTHER BRAKING SYSTEM
Virtually all of the problems with Silicone Brake Fluids relate to:-
Long/spongy pedal
Sudden loss of brakes
Hanging on of brakes
They reflect certain properties of silicone fluids identified by us over many years and recently ratified in SAE publications, namely:-
High ambient viscosity
High air absorption
High compressibility
Low lubricity
Immiscibility with water
Research has shown that the relationships between problems reported and properties identified may be expressed as follows:-
Long /Spongy Pedal
a) Compressibility, up to three times that of glycol based fluids
b) High viscosity, twice that of glycol based fluids, leading to slow rates of fill and retention of free air entrapped during filling, and hence bleeding difficulties.
Sudden loss of brakes
a) Air absorption. Gasification of absorbed air at relatively low temperature produces vapour lock effect.
b) Immiscibility (failure to mix) with water. Whilst the presence of dissolved water will reduce the boiling point of glycol based fluids any free water entrapped in silicone-filled systems will boil and produce vapour lock at much lower temperatures (100°C or thereabouts)
Hanging on of brakes
a) Low lubricity. In disc brake systems the sole mechanism for normalisation of system pressure upon release of pedal pressure is a designed-in tendency of seals to recover to their ‘at rest’ attitude. Low lubricity works against this tendency.
b) High viscosity exacerbates the effect of (a) above.
It should not be assumed, therefore, that the high price of silicone fluids implies higher performance in hard driving or even normal road use.
AP Racing glycol based fluids do not contain the adverse properties described above. The recently introduced Formula DOT 5.1 (http://www.apracing.com/info/info.asp?section=Fluid+Details_48) which exceeds the performance criteria of DOT 5 (Silicone), is suitable for all conditions likely to be encountered in modern driving conditions.

[Bounce]

What fluid do you recomend for OEM Shim,fast road and the odd track day.Apart from AP 5.1,im gonna get it from opie as there just up the road and they dont stock this.

[shimmy]

ive stuck in a couple of fluids and so have Simpsons but i guess something like the DOT5.1 from AP would be fine,


dot 5 (not 5.1) normally refers to Silicon Based fluid

[mattCSLnut]

Im due a brake fluid change,so thought id get some good stuff put in before the ring and spa,do you guys use castrol SRF which is on offer at the moment from Opie,athough still a lot more expensive than other race fluid,or is there another you use.;)
ATE Racing Blue seems to work well :thumbs: and readily available from ECP :beer:

[northernjim]

it seems AP do a few types of fluid now, I use motul rbf 660 myself

http://www.apracing.com/info/info.asp?section=Brake+Fluid+Details_94 (http://www.apracing.com/info/info.asp?section=Brake+Fluid+Details_94)

[Thorney]

We use AP for all the kits including the Alcon CSL Cup kits and on the race cars.

[Mark CSL]

I like Castrol SRF Castrol SRF is an ultra high performance brake fluid specifically formulated for competitive motorsport.
Exceptionally high dry boiling point and superb anti-vapour lock properties

[shimmy]

I like Castrol SRF Castrol SRF is an ultra high performance brake fluid specifically formulated for competitive motorsport.
Exceptionally high dry boiling point and superb anti-vapour lock properties

yep but your AP calliper seals dont:whistle:

[Mark CSL]

yep but your AP calliper seals dont:whistle:


:hahaha::hahaha::hahaha: I did not have AP Brakes i had HiSpec 6pot with 380mm Floating Performance Friction Discs :thumbs:

[shimmy]

feck me , Fuchs would have a heart attack :thumbs:

[mattCSLnut]

:hahaha::hahaha::hahaha: I did not have AP Brakes i had HiSpec 6pot with 380mm Floating Performance Friction Discs :thumbs:

Good God :smt107 I bet they worked well

[Dan]

:hahaha::hahaha::hahaha: I did not have AP Brakes i had HiSpec 6pot with 380mm Floating Performance Friction Discs :thumbs:

Fook me Mark they are awesome! :smokin: How much did they set you back?

I wonder if you can run the 6 pot Black & Yellow AP calliper with a larger than 355mm disc (bell & rotor), I know they do a 378mm kit for other applications but what about CSL's?

[david]

the M3 E92 AP kit in 378x36 AP 6P fits the hub and Csl rotor, you just have to modifie the braker between king pin and caliper

I have pics somewhere, let me check that, I'll comeback to it during weekend :smokin:

[DuncanR]

:hahaha::hahaha::hahaha: I did not have AP Brakes i had HiSpec 6pot with 380mm Floating Performance Friction Discs :thumbs:
Fook me Mark, you dont need any wheels size of them just run on the rotors mate !

[DuncanR]

I wonder if you can run the 6 pot Black & Yellow AP calliper with a larger than 355mm disc (bell & rotor), I know they do a 378mm kit for other applications but what about CSL's?

As a mere novice at this, would it be fair to say that the ONLY point of having bigger/better brakes is so that you can get on them much later in the corner, thus making your laptime quicker ? And if you are racing outbrake another competitor ... assuming that you do indeed get round the corner !!

Would it also be fair to say that if the above rings true, it requires much more skill and judgement in doing the above as timing is more critical, the braking zone is possibly smaller, and the margin for error much less?

If both of the above have any truth about them, would it be fair to say that at 52 years old, 53 in April, my PF's and AP's are more than adequate for what my brain could cope with? :hahaha:

[karbonkid]

How many Ltrs is needed to do a full Fluid replacement?

[mattCSLnut]

We'll find out on Monday @ Bedford TD :hahaha: ;)


As a mere novice at this, would it be fair to say that the ONLY point of having bigger/better brakes is so that you can get on them much later in the corner, thus making your laptime quicker ? And if you are racing outbrake another competitor ... assuming that you do indeed get round the corner !!

Would it also be fair to say that if the above rings true, it requires much more skill and judgement in doing the above as timing is more critical, the braking zone is possibly smaller, and the margin for error much less?

If both of the above have any truth about them, would it be fair to say that at 52 years old, 53 in April, my PF's and AP's are more than adequate for what my brain could cope with? :hahaha:

[alexk]

yep but your AP calliper seals dont:whistle:

Shimmy....
What do you mean ?
I have 4 litres of SRF waiting.
Thank you please

[northernjim]

As a mere novice at this, would it be fair to say that the ONLY point of having bigger/better brakes is so that you can get on them much later in the corner, thus making your laptime quicker ? And if you are racing outbrake another competitor ... assuming that you do indeed get round the corner !!

Would it also be fair to say that if the above rings true, it requires much more skill and judgement in doing the above as timing is more critical, the braking zone is possibly smaller, and the margin for error much less?


alternatively, having larger discs, but driving the same as with smaller, will mean less heat build up in the disc, and less chance of boiling your fluids:beer:

[DuncanR]

We'll find out on Monday @ Bedford TD :hahaha: ;)

Maybe so young Jedi !;)

[david]

How many Ltrs is needed to do a full Fluid replacement?

1.5 l for a turnaround with 6p front and 4p rear on my Csl to get a perfect and clear fluid change

[karbonkid]

1.5 l for a turnaround with 6p front and 4p rear on my Csl to get a perfect and clear fluid change
Yep F/R APs. Cheers :thumbs:

[s.mac]

1.5 l for a turnaround with 6p front and 4p rear on my Csl to get a perfect and clear fluid change

Thats seems a lot ?

Is ATE blue silicon based ??

[M5 Powered]

As a mere novice at this, would it be fair to say that the ONLY point of having bigger/better brakes is so that you can get on them much later in the corner, thus making your laptime quicker ? And if you are racing outbrake another competitor ... assuming that you do indeed get round the corner !!

Yes, it is all basically to do with heat. The bigger the disc, the more heat it can handle and dissipate when your constantly slamming on the anchors (unless you go the ceramic route).

Also it means the further you can go on the track / race without the feel changing.

From reading round, Thorney supply Alcons (badged CSL CUP) as the preference for racing use mainly because of the sustained sessions and mono-bloc calliper design which is stiffer. But for normal CSL trackday use, AP's are more than good enough and you can use the OEM BMW rear disc.

Best

Jonathan

[david]

Thats seems a lot ?

Is ATE blue silicon based ??


Yep, sorry, it's 0.75 l for turn around, AP bottles are 500 ml and not liter

ATE I don't know, I use only RBF600 or AP600 fluid for my car

[Dan]

As a mere novice at this, would it be fair to say that the ONLY point of having bigger/better brakes is so that you can get on them much later in the corner, thus making your laptime quicker ? And if you are racing outbrake another competitor ... assuming that you do indeed get round the corner !!

Would it also be fair to say that if the above rings true, it requires much more skill and judgement in doing the above as timing is more critical, the braking zone is possibly smaller, and the margin for error much less?

If both of the above have any truth about them, would it be fair to say that at 52 years old, 53 in April, my PF's and AP's are more than adequate for what my brain could cope with? :hahaha:

As has been said the larger rotor's will help with the dissipation of heat plus you get the added benefit of a little more stopping power:thumbs:

As a mere whippersnapper to your 52 Dunc I am 26 but I bet I can't hustle a car around any quicker than you can! :bigcry: :hahaha: ;)

Good thread this, nice to see what's available and what actually works and what doesn't :)

[TANKSLAPPER]

feck me , Fuchs would have a heart attack :thumbs:


ere Shimmy, this looks like it could develop into to one of those Fuchs BBK threads !

lol

[DuncanR]

Yes, it is all basically to do with heat. The bigger the disc, the more heat it can handle and dissipate when your constantly slamming on the anchors (unless you go the ceramic route).

Also it means the further you can go on the track / race without the feel changing.

From reading round, Thorney supply Alcons (badged CSL CUP) as the preference for racing use mainly because of the sustained sessions and mono-bloc calliper design which is stiffer. But for normal CSL trackday use, AP's are more than good enough and you can use the OEM BMW rear disc.

Best

Jonathan

Cheers Jonathan, im aware that heat is the big killer, but given that some say that OEM 's are fine, and that by going the AP/PF route your are even ...finer !!:hahaha:..thats how Beckham would have put it !
And all things being equal heat wise, the only advantage that a bigger brake setup has is shorter stopping distance surely? What im saying is that eventually if say a bunch of cars are all running various forms of BBK without heat problems, or any other brake related problems, then is the only advantage of say the biggest of the big... later braking? If so, my take on it is that if my bollocks, or anyone elses for that matter ! are bigger than the next guys rotors ... it soon becomes a moot point... doesnt it ??:smt102

[The Gorilla]

Hi,

I expect if you did a Brake test between Std CSL Brakes
and a 355mm BBK Kit then then the stopping distance
between the two would be very similar.

If you then continually repeated the Brake test, over a
period the BBK would still repeat its stopping distances
more or less, whereas the Std Brakes would start to fade somewhat.

Meaning if you are a 'Light' user of the Brakes, which
usually equates to a fast driver then for light Track use,
good Pads, S/S Hoses and some ATF Blue will be
fine.

If on the other hand you ride the Brakes hard, then the
Std Brakes, even with upgrades will be showing signs
of fade in two or three laps of any Track with spirited driving.

On the question of Brake Fluid, for Track Days, ATE Blue
is as good as it gets for the money.

Reason being, that if you require the extra 60 + degrees
dry and 100 odd + degrees in the wet that
Castrol SRF offers, then there is either something wrong
with your Brakes or your Driving.

Regards,

The Gorilla.

[3wheels3]

yep but your AP calliper seals dont:whistle:

How do you know this? I've heard others say it does but when asked they just say they heard it. I would like a definitive answer as am planning on using it.

Performance Friction clearly disagree with the statement.

...to maintain excellent vapour lock and corrosion protection, we strongly recommend that Castrol SRF be drained and refilled every eighteen months...

http://www.performancefrictionbrakes.com.au/techtips.php?pageId=47

Race Proven: Widely used in racing, from Formula One World sports cars to Group A and 500cc Grand Prix motorcycles;
High Boiling Point: The exceptionally high dry boiling point (higher than 300°C) makes Castrol SRF ideal for use under arduous braking conditions such as rallying or racing. Castrol SRF exceeds the boiling point requirements of DOT 5 brake fluids;
High Vapour Lock Point: Castrol SRF has a very high vapour lock point (the more important measure of high temperatures performance under actual braking conditions) and has the additional advantage of sustaining high vapour lock point characteristics during its service life;
Compressibility: The compressibility of Castrol SRF is very similar to that of current DOT 3 and DOT 4 fluids. It can therefore be filled into any braking system used in motorsport with the exception of those for which a mineral oil is prescribed;
Miscibility: Castrol SRF is miscible with all conventional fluids meeting the US Federal Standards FMVSS 116 DOT 3 and DOT 4, ISO 4925 and current SAE J1703. The miscibility of Castrol SRF with conventional brake fluids means changing the brake system to Castrol SRF is easy. Drain and flush out the conventional brake fluid with Castrol SRF then top up the system with Castrol SRF. Although Castrol SRF is miscible with conventional brake fluids, topping up Castrol SRF with conventional brake fluids will reduce the benefits of the product;
Compatibility: Castrol SRF is compatible with seal rubber and metal materials used in braking systems using conventional polyglycol brake fluids;
Bleeding: Castrol SRF is easy to bleed like conventional brake fluids.

[shimmy]

Pete Collen at AP told me and they have itvon their website as posted above. It says do not use Silcon based with A. Are you waitimg for a memo from the queen or something??


PHow do you know this? I've heard others say it does but when asked they just say they heard it. I would like a definitive answer as am planning on using it.

Performance Friction clearly disagree with the statement.

...to maintain excellent vapour lock and corrosion protection, we strongly recommend that Castrol SRF be drained and refilled every eighteen months...

http://www.performancefrictionbrakes.com.au/techtips.php?pageId=47

Race Proven: Widely used in racing, from Formula One World sports cars to Group A and 500cc Grand Prix motorcycles;
High Boiling Point: The exceptionally high dry boiling point (higher than 300°C) makes Castrol SRF ideal for use under arduous braking conditions such as rallying or racing. Castrol SRF exceeds the boiling point requirements of DOT 5 brake fluids;
High Vapour Lock Point: Castrol SRF has a very high vapour lock point (the more important measure of high temperatures performance under actual braking conditions) and has the additional advantage of sustaining high vapour lock point characteristics during its service life;
Compressibility: The compressibility of Castrol SRF is very similar to that of current DOT 3 and DOT 4 fluids. It can therefore be filled into any braking system used in motorsport with the exception of those for which a mineral oil is prescribed;
Miscibility: Castrol SRF is miscible with all conventional fluids meeting the US Federal Standards FMVSS 116 DOT 3 and DOT 4, ISO 4925 and current SAE J1703. The miscibility of Castrol SRF with conventional brake fluids means changing the brake system to Castrol SRF is easy. Drain and flush out the conventional brake fluid with Castrol SRF then top up the system with Castrol SRF. Although Castrol SRF is miscible with conventional brake fluids, topping up Castrol SRF with conventional brake fluids will reduce the benefits of the product;
Compatibility: Castrol SRF is compatible with seal rubber and metal materials used in braking systems using conventional polyglycol brake fluids;
Bleeding: Castrol SRF is easy to bleed like conventional brake fluids.

[mattCSLnut]

Hi,

I expect if you did a Brake test between Std CSL Brakes
and a 355mm BBK Kit then then the stopping distance
between the two would be very similar.

If you then continually repeated the Brake test, over a
period the BBK would still repeat its stopping distances
more or less, whereas the Std Brakes would start to fade somewhat.

Meaning if you are a 'Light' user of the Brakes, which
usually equates to a fast driver then for light Track use,
good Pads, S/S Hoses and some ATF Blue will be
fine.

If on the other hand you ride the Brakes hard, then the
Std Brakes, even with upgrades will be showing signs
of fade in two or three laps of any Track with spirited driving.

On the question of Brake Fluid, for Track Days, ATE Blue
is as good as it gets for the money.

Reason being, that if you require the extra 60 + degrees
dry and 100 odd + degrees in the wet that
Castrol SRF offers, then there is either something wrong
with your Brakes or your Driving.

Regards,

The Gorilla.
You're good value as always Gorilla :thumbs: Makes perfect sense to me :beer:

[DuncanR]

You're good value as always Gorilla :thumbs: Makes perfect sense to me :beer:
+ 1 ... but the question still remains ....do I use my brakes ?






























or my bollocks ? !!!!:hahaha:

[mattCSLnut]

+ 1 ... but the question still remains ....do I use my brakes ?



or my bollocks ? !!!!:hahaha:


Bollox first, then if U absolutely, positively, necessarily have to... brakes :hahaha:

[3wheels3]

Pete Collen at AP told me and they have itvon their website as posted above. It says do not use Silcon based with A. Are you waitimg for a memo from the queen or something??


P

That'll do for me, thanks.

[TANKSLAPPER]

+ 1 ... but the question still remains ....do I use my brakes ?

or my bollocks ? !!!!:hahaha:

You mite as well carry on using your bollocks Duncan. while they still work! :hahaha:

[alexk]

As suggested by Shimmy, I dropped an email to Mr. Pete Collen

alexk >

Dear Mr Collen,

I have a set of AP racing brakes (front and rear) for my BMW M3 CSL.
I would like to ask whether it is ok to use Castrol SRF brake fluid.
I heard from a friend that there is a problem with the seals and this brake fluid.


Can you please advise ?


Pete Collen >

Dear Sir

We have had similar reports back from the market that SRF can be aggressive to APR hydraulic seals. It should be compatible but if in doubt use APR fluid.

http://www.apracing.com/info/index.asp?section=Brake+Fluid_978

AP Racing Distributors are also listed.

Regards

Peter Collen

[_Nathan_]

Shimmey - SRF is DOT 4 not DOT 5, whilst it is based on a silicone ester it isn't in the class of DOT5 classified silicone fluids which is what I believe that note to refer to and indeed, it can be mixed with 5.1 fluid with no issues. No idea on issues with calliper seals though, I've used it on several cars in the past, one of which was running APs all round and no issues on that front.

I am of the school of thought that a decent fluid changed regularly is better than the ultimate fluid left in for 18 months so use the AP PFR660 DOT 4 stuff or similar.

[M5 Powered]

I spoke with Alcon technical HQ today.

They said Castrol SRF is fine to use on any of their callipers, and indeed on any competitors that they know of. They have never heard or seen seal failure owing to SRF brake fluid.

They were professional enough not to say it outright, but I personally suspect 'seal damage' is more about niche players protecting their own brake fluid sales, especially when you need 1.5 litres of the stuff for a CSL.

Alex, I'd stick with your bargain SRF if I were you mate :-) Just make sure you flush the old stuff through properly.

Best

Jonathan

[shimmy]

Shimmey - SRF is DOT 4 not DOT 5, whilst it is based on a silicone ester it isn't in the class of DOT5 classified silicone fluids which is what I believe that note to refer to and indeed, it can be mixed with 5.1 fluid with no issues. No idea on issues with calliper seals though, I've used it on several cars in the past, one of which was running APs all round and no issues on that front.

I am of the school of thought that a decent fluid changed regularly is better than the ultimate fluid left in for 18 months so use the AP PFR660 DOT 4 stuff or similar.


:thumbs:


tbh i hardly use my brakes so it is all a little irrelevant to me! :whistle:

[alexk]

:thumbs:


tbh i hardly use my brakes so it is all a little irrelevant to me! :whistle:

Sh1t, fuchsrohre is BACK !!!

[glendog74]

Fooking Hobbyist drivers - the lot of you! :clown:

[Bounce]

Fooking Hobbyist drivers - the lot of you! :clown:Thats me.;)

[3wheels3]

Think I'll probably go the ap600/660 type stuff. Although more expensive £10 or £20 more is insignificant in terms of expense of trackdays or even to get fluid change.

Further to the SRF debate. Castrol's own info spec sheet states unequivocally on page two:
Compatibility: Castrol SRF is compatible with seal rubber and
metal materials used in brake systems using conventional
polyglycol brake fluids.

If seals were to go because of SRF and something bad happened, would they be in trouble legally even if the Queen had sent me a memo?

http://www.castrol.com/liveassets/bp_internet/castrol/castrol_australia/STAGING/local_assets/downloads/s/SRF_B768.pdf

[shimmy]

Hi,

I expect if you did a Brake test between Std CSL Brakes
and a 355mm BBK Kit then then the stopping distance
between the two would be very similar.

If you then continually repeated the Brake test, over a
period the BBK would still repeat its stopping distances
more or less, whereas the Std Brakes would start to fade somewhat.

Meaning if you are a 'Light' user of the Brakes, which
usually equates to a fast driver then for light Track use,
good Pads, S/S Hoses and some ATF Blue will be
fine.

If on the other hand you ride the Brakes hard, then the
Std Brakes, even with upgrades will be showing signs
of fade in two or three laps of any Track with spirited driving.

On the question of Brake Fluid, for Track Days, ATE Blue
is as good as it gets for the money.

Reason being, that if you require the extra 60 + degrees
dry and 100 odd + degrees in the wet that
Castrol SRF offers, then there is either something wrong
with your Brakes or your Driving.

Regards,

The Gorilla.


:thumbs: i agree

[shimmy]

at the end of the day AP specifically say DONT USE Silicone based fluids.

IF BMW say dont use anything but Castrol Edge in the engines i listen, so im sticking to non silicone based fluids as well in my AP callipers :blalalala:

[glendog74]

This is what gets put into my APs when the car is at Simpson Motorsport. they claim it is as good as the AP branded fluid for a fraction of the cost. Has worked well for me so far :thumbs:

[_Nathan_]

That is what I use, cheap and it works just fine, no boiling of fluid ever.

[shimmy]

They sell something very similar in Aldi ;)

[_Nathan_]

I got mine from lidl :D

[DuncanR]

I got mine from lidl :D

I guess its the old story, just 1 or 2 refiners making the fluid, and a plethora of people getting the same fluids packaged in their own bottles !!:banghead:..... bit like Lager really ... real men drink Ale !!:thumbs:

[_Nathan_]

real old men drink Ale !!:thumbs:

:gayfight:

[DuncanR]

:gayfight:

Stella... invented for Lager louts who havent got the bollox to give the missus a smack when they are sober !!!! :hahaha:
Not that anyone should be doing that anyway, they are to be loved and cherished, and adored ... and shagged silly now and again !!

[mattCSLnut]

Stella... invented for Lager louts who havent got the bollox to give the missus a smack when they are sober !!!! :hahaha:
Not that anyone should be doing that anyway, they are to be loved and cherished, and adored ... and shagged silly now and again !!

:smt036 Spoken like a true gentlemen :hahaha: :beer: