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Discussion Starter #1
A few people have said I can use DOT 5.1 instead of DOT 4 for my brakes. Is this true?

The reason being, I need to fully flush my brakes because I boiled the fluid and I have a funny feeling its really old and full of water. They fade very quickly! Too quickly.
If I start braking from 70 on a slip road, before I've hit the roundabout I have very little braking power!

They aren't anywhere near as sharp as my sisters 1.6 SXi's brakes either, really spongy and awful.

So I'm changing the lot! Getting new pads and discs all round (all Pagid stuff) and fresh brake fluid.

Just wondering if I should spend the extra and get the 5.1?
 

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Discussion Starter #6
I can get DOT5.1 dirt cheap from work. So not too bothered about price. Just wondered if I could use it!

I bet you can't tell the difference during road use. Its the boiling point that is different right?
 

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I can get DOT5.1 dirt cheap from work. So not too bothered about price. Just wondered if I could use it!

I bet you can't tell the difference during road use. Its the boiling point that is different right?
Yes, the boiling points of DOT 5.1 are higher than DOT4.

Dry: 5.1 = 270 deg.C, 4 = 230 deg.C
Wet: 5.1 = 190 deg.C, 4 = 155 deg.C
 

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If your running standard hoses??? you'll get a little benefit. For full benefit you need braided hose's, and brake cooling helps too!!.
 

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Dot 4 Hight temp fluid is about £13. It's far superior to 5.1. Completely different chemical compound.

As packa says, get braided hoses. Doesn't matter what temp the fluid can operate at, the rubber hoses will deform long before the fluid boils.
 

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Discussion Starter #11
I'm thinking...

VXR brakes, braided hoses and brake ducts.
Surely my brakes wont boil after all that!

Just hope the brake ducts wont make my braking **** during rain.
 

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Drilled and grooved brakes on the front aswell. Put tights over your cooling ducts. Will catch big drops of water.... In my mind any way ;)
 

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Uprated brakes, hoses and fluids are all good additions to a car, but arent needed to resolve your issue. A simple service of your brakes and replacement with standard fluid will cure the issues. Standard brakes are more than up to the the job on the 1.9. I had a 1.9 that was running the same power as yours for over 40k miles on all standard brake parts and I never had an issue.
 

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Drilled and grooved brakes on the front aswell. Put tights over your cooling ducts. Will catch big drops of water.... In my mind any way ;)
I worry why you have tights ;)
 

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I'm using ATE super blue racing dot 4 fluid

280deg dry boiling point
198deg wet boiling point
 

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Dot 4 Hight temp fluid is about £13. It's far superior to 5.1. Completely different chemical compound.
Nope, DOT 4 and 5.1 are compatible. You may be confusing this with DOT 5 which is a silicone fluid and not compatible with DOT 3, 4 and 5.1.

As for the original question DOT 4 is perfectly adequate, especially the newer low viscosity versions designed for ESP.

MM
 
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