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The mkiv Supra Owners Club

Brake fluid


Guest Mycroft

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The little piece of paper that comes with Castrol SRF says to change it every 18 months.

 

I presume that is for racing conditions only, as it designed for racing conditions so it should last a fair bit longer as a road use fluid. Unless it is dramatically hydrophilic.

 

I put it in last Autumn so its too early to tell yet.

 

What you need is someone like Chris Wilson to tell you.

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Guest Martin F

 

I think it is the hygroscopic properties of SRF which dictate the maximum time before replacement, not so much the type of use.

 

 

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Guest Mycroft

The reason for asking is that in my car I have had both the SRF and the Motul, both have shown 3+% water after less than a year (I am fortunate in having testing facilities available) this drops the BP down by about 40% in both cases.

 

At the same time as I did the first of these changes (to SRF) my near neighbour with a 996 Porsche had his brake fluid changed to ATE Blue Racing, my car is for the most part garaged, his is not, I tested the Motul last week and at the same time tested his, I have 3.88%, he has 0.64% so next week I'm changing to the ATE, it says on the can that it is good for 3 years, well almost 2 years in the Porsche, outside in the rain and snow seems a good test to me.

 

Whaddya think?

 

The old 'rule of thumb' says 1.25% is the threshold for the old heave-ho, that means  (working backwards) I should have ditched the SRF and Motul after just 3-4 months max!!!

 

(Edited by Mycroft at 9:36 am on Mar. 18, 2002)

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In a true race car I change fluid between every race, SRF or Motul should last a year, but maybe change it every 6 months if doing track days and you need all the wet boiling temp available. SRF is the best, Motul 600 is a close second. I stock both, and am now a Motul distributor, so will beat any genuine price on the fluids and oils they do. they do some superb race and hi perf road car oils BTW, see http://www.motul.com

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Guest Mycroft

Don't suppose you can get me any ATE Racing Blue?

 

The suppliers name given to me didn't 'check out' today.

 

I rather like the idea of having a fluid that will last 2 years without degrading!

 

If you can't supply do you know of a supplier, it seems to be readily available in Holland, and if you can't help I'll ask Flavio for a contact!

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Quote: from Mycroft on 7:27 pm on Mar. 18, 2002[br]Don't suppose you can get me any ATE Racing Blue?

 

The suppliers name given to me didn't 'check out' today.

 

I rather like the idea of having a fluid that will last 2 years without degrading!

 

If you can't supply do you know of a supplier, it seems to be readily available in Holland, and if you can't help I'll ask Flavio for a contact!

 

No sorry, never seen a UK supplier, nor have I found a true hi perf fluid that ISN'T hygroscopic! Given the running costs of these cars I feel an annual fluid change, or even bi-annual is small beer.

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Guest Mycroft

I know what you're saying...but...I think it is a fag to do... and I keep thinking of that Porsche sat there with none of this 'hassle'.

 

Expense is not an issue really, just at the weekend, I like to drive, my maintainance routines are already very crowded, just think, 3 years, no change, 500+deg fluid all that time, and (seemingly) £10 for a ltr.

 

Alfred Teves boys, I think, may be the smarter ones in the end.

 

I'll keep looking, thanks anyway.

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Quote: from Rob on 11:00 pm on Mar. 18, 2002[br]One other thing, is it possible to change/bleed the brakes without removing the wheels?

i.e. has anyone done it or is it a right pig?

 

It may be possible with open spoke type rims. I think i did Christians at Bentwaters with the wheels on, but he has AP six pots on it, so the nipples may have been easier to get at.

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Guest Mycroft

Have at last sourced the Racing Blue Fluid and it is available here 0208 956 5050.

 

One other thing is that it goes 'grey' when the water content goes above that 1.25% threshold...it actually tells you when it should be changed!!

 

500+BP dry, and who cares about the wet, unless you are a very rare type of colour blind the wet is a non-issue.

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I know I'm a little late coming in on this one and I assume I'm the only one that doesn't know but;

What's scary about dot 5.1? - A friend of mine at a local Ferrari dealership did a service on my car recently and I'm sure he put Dot 5.1 in when he replaced the fluid.

 

In the next couple of days I'm hoping to change my front brakes. So, if I have this 5.1 in my braking system, this would be a good time to remove it.

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I think 5.1 is a bit in tolerant to contamination if I remember correctly so you've got it great if not you got to majorly overflush the system to make sure its not got any other oil types in there....

 

I think that's right but I shall await correction... :)

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Guest Mycroft

The 'cracked' Glycol base for DOT 5.1 is more prone to water absorption and more importantly steam release than the simple glycol in DOT 4.0, this means that although it may only contain (say) 1% of water it will feel to the pedal like 3 or 4%.

 

I am now certain that the ATE stuff is good gear, my neighbour (who returned from work just now) assures me that his brakes feel more 'sensitive' and there is no difference in the pedal movement when he does the odd trackday with the POC. He cooked the last stuff (hence the change), but he cant remember what the old stuff was. He knows that the Porsche spec in his 'folder' (?) is 5.1! so it was a 5.1 that much is fairly certain.

 

 

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Guest Mycroft

My Super blue Brake fluid arrived today, just 24hrs after ordering!

 

I call that good service.

 

The grey starts to happen only when the fluid has absorbed sufficient water to reduce the BP to 500F. and is grey at 470F.

 

The fluid in the Porsche over the road is still BRIGHT BLUE, 2 years on!

 

All change on Tueday, I won't keep you posted as it seems likely that a Yearly 'All OK' will be the only word after Tuesday!

 

Reason for Edit,

The Stuff is also available in bright Yellow, same trick, different colour, now ain't that cool!

 

(Edited by Mycroft at 6:46 pm on Mar. 22, 2002)

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