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Hispec Big Brake Kit....... But Which One?


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Well just when you think you have it all sorted and your about to hit the buy it now and............You spot something else. Demon Tweaks. Bloody Demon Tweeks, they sell a brake fluid that needs changing every 18 months. Its boiling point is 270-300 deg C instead of the dot four normal of 155deg C required for dot 4 status. So with my current issue just being heat. I should be able to swap the fluid for this other Castrol srf dot 4 race fluid and I shouldn't get any issues. So were is the catch.......Well its £50 PER LITRE!!!!!

Yes £50 PER LITRE!!!!! Anyone tried it???

 

Maybe thats how the racers have got round the solid discs boiling their fluid???

 

I have a similar problem with my Motorcycle. It has one front disc which when ridden hard heats up and eventually the lever goes soft and needs a couple pumps and it comes back with numbness and eventually cools after couple seconds not being used and brake bite is back.

 

I bought Castrol React brake fluid for the bike but have not tested it yet. This has a 210deg C boiling point and is only £12 per litre. So maybe I should keep the current setup and change the fluids to the React Performance and then if it doesn't solve the problem then try the React Racing SRFfluid which was clearly made from unobtainium as its so expensive.

 

Whats the thoughts on this??? I'll try the React Performance stuff first but has anyone used the Castrol SRF race fluid??? Or would you get the Caterham Setup as I was considering???

Chris.

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Hi Chris

 

The only issues I ever knew about with race brake fluid was that it absorbed moisture and was not for long term road use. If the fluid you are talking about lasts 18 months I can't see any problems other than the price. But if the brakes are getting hot enough on the road to cause the fluid to over heat I think I would change the brake set up rather than the fluid. Creating that much heat constantly over time could effect other components. I think vented discs with cooling ducts directed on them decent pads should be enough for road use. Even a track car can still have issues with overheating brakes depending on the track etc.   

 

Mark

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The critical thing with all high spec fluids is regular changes - no point having top spec Dot 5.1 full of moisture and some false sense of security. Also always use small new containers rather than having a large container with its seal broken - half full - collecting moisture in a damp shed.

So bulk buying is really a false economy unless you use it all quickly - ie trade type use

If you have a friendly decent garage they can test fluid for moisture content .

If in doubt bleed it out - 15 min job and keeps the nipples freed off.

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Hi Chris

 

The only issues I ever knew about with race brake fluid was that it absorbed moisture and was not for long term road use. If the fluid you are talking about lasts 18 months I can't see any problems other than the price. But if the brakes are getting hot enough on the road to cause the fluid to over heat I think I would change the brake set up rather than the fluid. Creating that much heat constantly over time could effect other components. I think vented discs with cooling ducts directed on them decent pads should be enough for road use. Even a track car can still have issues with overheating brakes depending on the track etc.   

 

Mark

 

Hi Mark,

             Under normal road use the brakes are fine. Going for a wee quick drive they are fine. Hill climbs they are fine as they are short. However big speeds long braking down hill repeatedly over and over at race pace chasing bigger more powerful cars is what gets them hot. I know they are hot as they loose their bite. I've never had them over heat to the point they have stopped working but I don't think I'm too far off that. Its a prolonged heavy use heat thing. I think the better fluid is the ticket. As Andy said, regular fluid change ever two years should be fine. The stuff i'm gonna try first is the react Performance. The £12 a bottle stuff as I've already bought some for my motorbike. We will see how that performs first.

 

I currently have 1144 mintex pads but have been told to switch to Ferodo 2500 or 3000 any thoughts or experiences???

 

Chris.

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Two forms of "fade" - which do you feel you are having on the Spitty Chris?

 

Fluid fade is squashier than normal pedal or complete loss of pedal caused by the fluid boiling in the calipers or slave cylinders.  This is what you're getting on your bike The boiling point of the fluid will fall as it absorbs water.  When changing fluid it is well worth pushing the caliper pistons right back in (same for slave cylinders too) as otherwise it is most unlikely you'll be able to flush all the old fluid out.  As noted above special racing fluids have higher boiling points, at a price, and will need changing more often to retain their full benefits.

 

Pad fad is when you have a hard pedal (harder/higher than usual sometimes) but reduced or severely reduced stopping effect.  This is caused by the discs /pads overheating leading to the pad material gassing.  Apart from bigger or vented brakes, different pad materials and/or slotted/grooved/drilled discs can help.

 

I've never experienced fluid fade with the Vitesse, but I did on my 1500 Herald (and right scary it was too).  That had type 14 calipers fitted at the time, which where just too small for the abuse I was giving them.  Fitting Vitesse 2L brakes fixed that problem permanently.  Back then I knew nothing about alternative pads so didn't try that option.

 

I have had pad fade with the Vitesse - even with Mintex 1144, but that was after some fairly extreme treatment involving very big Alps.  I now run Ferodo DS2500, which we have been unable to fade though they do have slightly less cold bite than the 1144. They were expensive but have performed and lasted really well and not chewed the discs up either.  John D recommends Mintex M1155, which is pretty similar spec to to the DS 2500 I think.  You might find the Ferodo DS3000 a bit lacking in cold bite.  I had several people suggest Hawk pads to me but I've not tried them.

 

Had you thought of changing to Vitesse/GT6 front end or does the extra weight put you off?

 

Nick

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If you're just losing bite it's the pads overheating, upgrading fluid isn't going to help that.

 

If the fluid overheats it boils and the pedal will go to the floor. Not nice. It's highly unlikely to do this unless the fluid is old and impregnated with water, having said that, normal, high quality fluid changed every 2 years should be fine.

Given the weight of your car I'd be inclined to try some DS2500 pads, they're as good as it gets for a road usable pad, if a bit hard on discs. I ran them on a Cerbera and was very pleased with the improvement they gave.

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Had you thought of changing to Vitesse/GT6 front end or does the extra weight put you off?

 

Nick

 

Hi Nick,

           I think I was on the verge of the fluid going as I could feel it in the pedal. Initial bite on the pads had also gone but they were still slowing perfectly well. I looked at changing to GT6 front ends but the cost is too much. By the time you take into account the new uprights(canleys) or brackets and calipers etc I might as well get the Caterham kit.  Which I will if this fluid and pad swap doesnt work but to be honest I'm very optimistic.

 

I've just picked up these Ferodo old stock DS2500 for £42 delivered.

 

http://www.ebay.co.uk/itm/301746291146?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

 

Some things are meant to be. 

 

Chris.

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My experience of DS3000 is amazing bite from cold and completely consistent brake force even when toasty - this is on a PI saloon running Volvo calipers and vented discs - the pads were re drilled ones for a Ferrari 328 or Aston DBSV8 - they are very aggressive on discs - change the pads , change the discs

DS2500 are very good for the track and road but you need to follow the instruction to bed them in - they are good on discs unlike mintex 1144's which are far more aggressive . No experience of 1155, 1166 or Hawk

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Itiejim,

          DS 2500 just bought. I'll change the fluid too. How much do the spitfire calipers weigh???

 

Sorry, I don't know. I run GT6 brakes front and rear.

 

That's a good buy on the 2500s, I'm sure they'll do the trick.

 

Chris.

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