Ian - I guess as soon as Sean confirms what he has in stock and how much we need I will get one of my guys in UK to pick it up …
Pesky - No worries - will do
Sean - Looks like at least 6 litres so far so let us know what you have - I assume �20 is including VAT ??
Rox
Found an interesting article that talks in depth about brake fluids. Will post a link to the complete article this evening when I get home and can load it to my site. Seems to make sense but then I’m no expert on these things. Here’s a taster which may help answer your questions. Don’t shoot the messanger anyone who disputes it, just thought it may help
FROM THE ARTICLE
Now we have to talk about the incompatibilities of the old (DOT3/4)and two other newer types of fluids- the silicones, most of which are labelled as DOT5, and the silicon esters (which are altogether different than the silicones). These fluids, whether they’re called DOT5 or gorilla snot, aren’t miscible in the glycol or borate ester fluids. They separate when mixed, leaving you little pockets of wet hygroscopic old fluid, slowly corroding your system. Bad news. If you want to use the silicone stuff, be my guest- but I doubt that you’ll ever get a good pedal feel. Flushing with denatured alcohol, followed by a thorough compressed air drying is a minimum requirement, followed by flushing a lot of the silicone stuff through. Silicone fluid has no place in my cars, but you may have different experiences.
I’ve been doing a great deal of research into braking systems lately (for a couple of race/track cars I’m working on) and along the way. I’ve picked up the catalogs from JFZ, Wilwood, Alcon, and Tilton- all manufacturers of braking components of the highest quality, used in many forms of racing. Here are some quotes from their technical literature having to do with silicone fluids.
From the Tilton Engineering Brake and Hydraulic catalog: “WARNING: Despite advertising claims, silicone brake fluid is unsuitable for racing at high temperature because of its compressibility. This is why many people who have tried silicone fluids have complained about the brakes going away after 10 or 15 laps. Currently, no major team that taxes its braking system to the limit is using silicone brake fluid.”
From the JFZ Engineering Braking Products catalog: “Note: We strongly recommend that you do not use silicone brake fluid with any of our products. We have tested extensively and found that silicone fluid has properties that may cause seal swelling and may not be appropriate for racing use.”
From the Wilwood catalog: “We do not recommend the use of silicone fluids. Silicone fluid is also a highly compressible fluid and will cause your pedal to feel spongy, and get progressively worse as it heats up.”
All these companies recommend the use of DOT3/DOT4 fluids- and periodic flushing of the system.
I am not sure on the statistics but, I believe that more racing teams in all the various types of racing prefer DOT 4 instead of DOT 5 for the consistant brake pedal feel. Maybe someone else has facts.
AND A BIT MORE FROM FURTHER DOWN THE PAGE
I know that the Castrol SRF fluid in Europe is, as Castrol holds the patent. Apparently, the room-temp viscosity is low enough that it avoids the bubble entrainment problem and bleeds well - but it will not mix with ANY other fluid, DOT3, 4, 5, or whatnot. So you’re down to flushing with alcohol to clean out the system again.
John
No problem then John.
DOT 5.1 is of the DOT 3 & 4 family.
The only odd one out here is the DOT 5.
I wonder why the jump, some marketing b.s. I suppose.
I am assuming SRF is DOT 5.1
SRF is a Silicon Ester fluid so gets mixed up with pure Silicone fluid ( DOT 5 ) and its absolutely not DOT 5 !!
Its actually Dot 3/4 compatible but with much higher boiling pints wet and dry so mixing it is not a great plan as you get no benefit - so best to purge the old with new SRF and no problem - unless of course you have been using pure Silicone fluid and then you have a problem
Also it comes in a plastic bottle now with no seal, so go figure how hydroscopic it is …
Also it comes in a plastic bottle now with no seal, so go figure how hydroscopic it is …
Does this mean that I didn’t need to throw away the quarter bottle I had left when I last changed my SRF ?? (Booga !!)
Andy - any chance of getting a bottle for me as well ???
Brake fluid ‘What’s in a number’. It’s a fairly old article but I found it interesting.
John
I know that the Castrol SRF fluid in Europe is, as Castrol holds the patent. Apparently, the room-temp viscosity is low enough that it avoids the bubble entrainment problem and bleeds well - but it will not mix with ANY other fluid, DOT3, 4, 5, or whatnot. So you’re down to flushing with alcohol to clean out the system again.
jaycee
excellent read and just what i was wondering about… very many thanx
so if i want to use SRF now, i’ll have to purge my system with alchohol… i was hoping not but always thought it was likely.
How did you guys who have already moved to SRF do this ? wheredya get the stuff to flush ? or did you take the easy way… and not bother ?
Rox
I think I first used SRF in the latter part of 2001, if not, it was definately in the first quarter of 2002.
I’ve just checked my tin of the stuff, & it is DOT 4.
In order to get a hard pedal, the system has effectively always been flushed with SRF, as we usually go round the car bleeding each caliper at least twice. Hence, out of a 1 litre tin, we tend to end up with about 150-200ml remaining.
PS Going out to buy a brake parachute tomorrow, just in case
PS Going out to buy a brake parachute tomorrow, just in case
LOvL
The DOT4 bit doesn’t really mean that it will mix with other DOT4’s - the DOT rating has more to do with its characteristics (boiling points and the like), not the chemical composition.
From reading the article, Silicon Ester (SRF) and borate ester/glycol (my Castrol RS) aren’t capable of being mixed, even tho’ both are DOT4, so they seperate and leave pockets of water - which will both rust the system and boil leaving your brakes with the problem that we are trying to solve in the first place.
Don’t forget to pack your rip-cord …
Mike
OK - no problem
Rox - I’ve always used SRF in any track, sprint, rally car i’ve owned and TBH have always just flushed out what was in with new SRF - usually leaving very little, if any from 1 litre …
There is stacks of info on the web, much of it conflicting - I’m quite happy to purge normal dot 4 with SRF though TBH - see last but one paragraph …
Lifted from 0800 brakes web site in NZ:
Which brings us to the next weakest link in the chain. The Brake Fluid.
There is no point having materials sitting in the wheels able to handle 700+ degrees C if your brake fluid is going to boil as soon as you put them to the test. First let us dispel a few common misconceptions. You do NOT want to use a DOT 5 brake fluid. DOT 5 is the rating given to silicone brake fluid (more correctly called Silicone Basal Brake Fluids or SBBF�s) We must also not confuse �silicone� fluids with �synthetic� fluids. Silicone fluids are not miscible (mixable) with conventional fluids however synthetic race fluids can be mixed with conventional road fluids. Very handy if you have rolled the car in the back of beyond, tipped all your race fluid out of the reservoir, but the car will still be driveable if only you can top up your master cylinder. Remember, mixing standard brake fluid with your race fluid will proportionally dilute the properties of your race fluid.
Now back to the DOT rating. All brake fluid, apart from silicone fluids, are hydroscopic which means that they will absorb moisture. The higher the DOT rating, the less hydroscopic they are. In other words, the less moisture they will absorb over a given period. Over time this will contribute to a brake fluids �wet boiling point�. Using a high DOT rating in a road car theoretically means that you will not have to change your fluid as often as you would if you were using a lower DOT rated fluid. This however does not apply to a race car as a race cars brake system produces so much moisture and debris that the laws of longevity are not really relevant.
Silicone fluids are NOT hydroscopic, meaning that they will not absorb moisture. This however is their downfall. All brake systems produce moisture. Particularly race brake systems as it is the extreme temperature changes that cause excessive moisture build up. As the brake system produces moisture, a conventional brake fluid will absorb it but a silicone fluid won�t. The moisture is still in the system but instead of absorbing into the brake fluid (admittedly reducing its boiling point), it just sits there in little water pockets waiting for the brake system to get hot so that it can vaporise. Even a well soaked brake fluid will have a higher boiling point than water.
RACEBRAKES 0800BRAKES handy hint: Avoid the risk of vaporizing your brake fluid at all costs. The results of a brake pedal going to the floor can be extremely hazardous to your health. Replace your silicone fluid with a proper race fluid. We have found ELF�s XT3167 to be very good value for money. We know that silicone fluid is kind to your paintwork if you spill it, but what are your priorities?
Keeping in mind that a DOT 5 is a silicone fluid, the highest DOT rating generally available for a conventional or synthetic fluid is a DOT 5.1 (notice the point one and we also note that there are DOT 6 fluids out there) So while a DOT rating has its place, what we are really looking for in a race fluid is a high dry boiling point. Interestingly, two of the best race fluids on the planet today, Brembo�s LCF600 Plus (this is the stuff that they tip into the Ferrari F1 cars and is available from RACEBRAKES 0800BRAKES in 500ml bottles) and Castrol�s SRF are both rated as DOT4+.
Incidentally, the minimum dry boiling point requirements of a DOT 4 fluid is 230 degrees C, DOT 5 (silicone) is 250 degrees C and DOT 5.1 has a minimum dry boiling point requirement of 260 degrees C. Admittedly, most off the shelf DOT4 road fluids will exceed the minimum requirements. In comparison, Brembo�s LCF600 Plus has a dry boiling point of 316 degrees C and Castrol�s SRF has a dry boiling point of 310 degrees C.
The other (and some would argue most important) advantage of a proper race fluid is that it is a lot less compressible than standard road fluids. In other words, they are less squashy. The less compressible race fluids help eliminate a lot of your spongy pedal and long pedal travel problems. It really is a shame when people spend hundreds of dollars outfitting their vehicles with braided hoses to firm up the pedal, then go and put a road fluid (or even worse, a silicone fluid which is highly compressible) into their car to save themselves a few dollars??
And just in case - Castrol Technical information
Castrol SRF Brake Fluid
Technical Information
Castrol SRF Racing Brake Fluid is an ultra high performance product formulated specifically to satisfy the ever increasing stresses placed upon the braking systems used in international motorsport. The exceptional performance of Castrol SRF is due to a novel silicon ester technology pioneered by Castrol and unique to the extent that it has been granted patent-protection in numerous countries throughout the world.
Castrol SRF evolved as a direct result of Castrol’s ongoing Research and Development program for brake fluids which identified this silicon ester technology as providing considerable performance benefits when compared with conventional glycol ether borate ester fluids.
Following exhaustive laboratory tests at Castrol’s International Technology Centre in the UK, the final formulation for Castrol SRF was subjected to an extensive road-test programme on the Gross Glockner and Stelvio passes high in the Austrian and Italian Alps. It then underwent an independent track test program conducted by a famous Formula One racing team. Their assessment was that “Castrol SRF is the best racing brake fluid we have ever used.”
Subsequently, Castrol SRF was offered to top flight racing and rally teams throughout the world including most of the Formula One teams, the all-conquering Jaguar and Mercedes -Benz sports car teams and the Audi, Nissan and Toyota rally teams. Enthusiastic recommendation by these experts soon created an immense interest in Castrol SRF throughout the whole spectrum of national and international motorsport. Today, Castrol SRF is regarded by the international motorsport community as being without equal and it is chosen not only by factory-supported teams but by private competitors throughout the world.
All conventional brake fluids used in cars and motor cycles are hygroscopic, that is, they absorb water from their surroundings. Strange though it may seem, the flexible hoses incorporated in braking systems are permeable to water and in time enough, water can find its way into the system via the hoses, and seriously affect the brake fluid’s performance. This water reduces the boiling point of the fluid (ie, it lowers the temperature at which gas bubbles begin to form). When these bubbles form, they turn a virtually incompressible liquid into a mixture of gas and liquid which can be compressed quite considerably, thus severely reducing the efficiency of the brakes. In this situation, a driver finds that the brakes feel spongy. Brake-pedal travel will increase and it may be necessary to ‘pump’ the pedal to get the brakes to function effectively. However, when the brake fluid reaches a temperature at which the water in the fluid causes gas to be produced, which is equal to the volume swept by the piston in the rake master-cylinder, vapor-lock occurs and the brakes become inoperative. When this happens, the first indication the driver has that something is wrong is when he applies the brakes. The pedal goes down to the floor and the car carries on at undiminished - and possibly fatal speed.
The silicon ester technology in Castrol SRF addresses this problem in two ways. Firstly, Castrol SRF is less hygroscopic than conventional brake fluids - it absorbs less water in a given time. Secondly, unlike conventional glycol ether fluids, Castrol SRF reacts chemically with the absorbed water to reduce its adverse effects, thus preventing the fluid’s high temperature performance and safety margins from deteriorating as rapidly as they would otherwise do.
Castrol SRF exceeds the US Federal Standards FMVSS 116 DOT 3 and DOT 4, ISO 4925, JIS K2233 and current SAE J1703 and is miscible with all conventional brake fluids conforming to these standards. However, mixing Castrol SRF and conventional brake fluids will reduce the benefits of Castrol SRF. It is strongly recommended that conventional brake fluid be drained from the system before flushing and re-filling with Castrol SRF.
The wet boiling point of Castrol SRF, 270 C, is vastly superior to the minimum requirement of 155 C demanded by the current US DOT 4 specification. The product’s typical dry boiling point of 310 C is likewise outstanding. This ability to withstand temperatures in excess of 300 C, and its superior resistance to the effects of absorbed water, have established Castrol SRF as the world’s premier fluid for the hydraulic brakes used in all forms of motorsport.
Back To Castrol SRF
Err - that’s that then !!!
Thanks Andy - I’ll read it later though
Sean
Looks like we need 10 litres - so can you confirm please
Thanks
Andy
Thanks for that…
It says that SRF is miscible with conventional barate ester/glycol fluids… contradicting the other article a little, however it does say (as mentioned previously by your good self) that mixing them reduces the advantage. Mind you i guess once youve replaced your original change to SRF a few times it’ll get better and better… But it’ll only be recognisable if you get anywhere near 300C brake temps… I would reckon you need a good bit more than a litre the first time you fill up with SRF tho’ if you want to get close to purging your old stuff properly. You should really get yourself some alchohol
Any chemists out there who can tell us if silicon ester will mix with borate ester/glycol
just picked up my 2 litres of SRF for the great price of �40. Thanks alot Sean that will be in the car shortly.
No worries Chris nice to meet you.
10 litres shouldn’t be a problem. I have ordered some more. When do you need it for???
Sean…
OK - Sean’s out of stock but its on order.
As soon as I have it I will let you know and we can work out money and transport logistics.
Yeah Sorry Andy, Brom (the big lad) said that someone popped down for some. We only have about 6 litres in stock and selfishly we don’t want to leave ourselves with none (Sorry)
I have ordered a rack load of the stuff and a load of castrol RS (�20 for 4 litres).
I will post on here as soon as I have it in stock.
Sean…
Sean - yeah no worries - So you know its a guy called Ian ( Stan ) - who is picking it all up for me - tall Ginger hair …
The RS - motorsport I guess ?
Sean - yeah no worries - So you know its a guy called Ian ( Stan ) - who is picking it all up for me - tall Ginger hair …
Yeah, right!
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