I'm changing the brake fluid next weekend and had planned to use Castrol Super DOT 4 as I have done previously. However Halfords no longer stock it as they now have their own range of performance brake fluid. The types they stock are DOT 4 ESP and DOT 5.1. Should I go for one of these or something else?

I thought the 5.1 would be better suited. Wait for a second opinion...

On performance cars, I've always been told Super DOT 4 is a better bet than 5.1 so I'd find a different supplier and stick with it

Chris

On performance cars, I've always been told Super DOT 4 is a better bet than 5.1 so I'd find a different supplier and stick with it

Chris

On the bottle for the halfords own 5.1 it states it meets or exceeds the standards for among other things super DOT 4, I have to say though I'd be more comfortable with what I already know works well.

From my experience, also having been told super dot 4 is "better" than 5.1, I have actually found 5.1 to be much better. I was advised for dot 4 super in the octavia, and noticed no change over the normal 4 that was already in. In the Fabia, i have 5.1, the change was very noticable indeed. I'd use 5.1, and change it every 6 months.

I use ATe Super Blue Racing

Dry boiling point 50 deg C above DOT 4

Wet boiling point 45 deg C above DOT4

Way better than others and worth a search to find.

be carefull!!! make sure the fluid you buy is NOT silicon based otherwise you could end up damaging the seals on the calipers and or servo/master cylinder... i allways use the mintex dot 5.1 and iirc you can buy a 5 litre bottle for about £25 from any decent motor factors

iirc super blue is a Dot5 and not a dot5.1 and therfore wont be suitable.... i could be wrong tho.... sombody will correct me i'm sure.

Silkolene Pro Race 2000

In 40k track miles I have never ever boiled it

The reasons for the super 4 over the 5.1 is:

It is less hydroscopic so you can keep the standard change intervals

The dry boiling point is only slightly less

The wet boiling point is usually better

be carefull!!! make sure the fluid you buy is NOT silicon based otherwise you could end up damaging the seals on the calipers and or servo/master cylinder...

Given the amount of warnings on most bottles of this stuff I would hope nobody would make this mistake but good advice none the less.

Silkolene Pro Race 2000

In 40k track miles I have never ever boiled it

The reasons for the super 4 over the 5.1 is:

It is less hydroscopic so you can keep the standard change intervals

The dry boiling point is only slightly less

The wet boiling point is usually better

Any tips on where I could buy a litre?

I've just changed mine for the Halfords Dot4 - I saw the note on the bottle stating that is exceeds DOT4 standards and wondered if it is actually Super DOT4 in disguise.

I've just changed mine for the Halfords Dot4 - I saw the note on the bottle stating that is exceeds DOT4 standards and wondered if it is actually Super DOT4 in disguise.

I would have expected it to state it meets or exceeds super DOT 4 in that case though as it does on the back of the 5.1 bottle.

Demon Tweeks and you get a 10% Briskoda discount.

DOT 3 401ºF 284º F

DOT 4 446º F 311º F

DOT 5 500º F 356º F

DOT 5.1 518º F 375º F

The Silkolene figures are 572ºF and 383º F dry and wet respectively Boil that and you have got serious problems!

Isn't dot 5.1 the same as super Dot 4.

IIRC they called it super dot4 as too many people were getting confused that dot 5.1 was silicon based, when infact it isn't?

Isn't dot 5.1 the same as super Dot 4.

IIRC they called it super dot4 as too many people were getting confused that dot 5.1 was silicon based, when infact it isn't?

Noooo!

IIRC, DOT4 and Super DOT4 are "compatible" in that you can mix the two different types if you have to.

5.1 is different enough to require a complete purge of any existing DOT4 fluid to replace with 5.1

I think mine's running on 5.1 at the moment, but I ought to change it as it's been in there for a couple of years and as it's more hydroscopic as Jon said, any serious braking may get the fluid boiling :eek:

Mine needs a service, oil change, brake fluid change and remap at the same time, so starting to enquire for a packaged price

I thought DOT 5 was silicon based and 5.1 was not?

Some site

Ferodo UK

EDIT yep Dot 5.1 is NOT silicon based, only DOT 5 is:

Brake fluid - Wikipedia, the free encyclopedia

I thought DOT 5 was silicon based and 5.1 was not?

Some site

Ferodo UK

yes true!

also all dot 5 & dot 5.1 is normally a red colour too to avoid confusion with dot 4 stuff

so why is dot 5.1 incompatible with 4 when a lot of places seem to say it isn't?

EDIT : See links i just editing into previous post

In so many words, DOT 5.1 fluids are simply DOT 4-type fluids which meet DOT 5 performance requirements. Because of this, they typically can be mixed with DOT 3 or DOT 4 fluids without concern. In some circles, they are even referred to as

I take back what I said about DOT 4, Super DOT4 and DOT5.1

That StopTech doc makes for some interesting reading

Bloody confusing about the dot naming still, which I guess is why it's called Super 4 as well as dot 5.1

Finding Super DOT 4 locally is proving more difficult than expected. :(

I found that too, Eddy - hence I used the Halfords DOT4

You did see the link above from the stoptech page which states that dot 5.1 is sometimes called super dot 4, eg that they are the same thing?

I went and looked at the DOT site.

- DOT 5.0 IS silicone based

- DOT 5.1 IS NOT silcon based

AP Racing, Castrol SRF, ATE Superblue / TYPE 200 and Wilwood 570 Brake Fluid - RaceShopper.com

Brake Fluid Comparison

http://www.motorspot.com/itm_img/DOT_5%5B1%5D.1_Brake_Fluid_8070_(GB).pdf