whats the difference. Brake fluids

[Gareth_C]

Between DOT 4 and DOT 5.1 brake fluid. Im not going to put the average local motor factors stuff in just encase so and suggestions as what to use.
Cheers Gareth

[Stuart]

Most lairy DOT4's are better than DOT5.1's BUT 5.1 absorbs less water than any DOT4.

I run cheapy motorfactor Mintex 5.1 in all cars and never had an issue with it (even with carbon metallic pads which dump heat into the calipers/fluid like there is no tomorrow). £3/Litre FTW

[jeremy fisher]

As I understood it, DOT5.1 is silicone based and hydrophobic, as in it will not absorb water whereas DOT4 is hydroscopic and will absorb moisture, DOT 5 is like DOT4 but with higher wet and dry boiling points. DOT5.1 sounds good but if any water gets into the braking system rather than being absorbed and dispersed within the brake fluid it will 'pool' in certain areas and possibly cause corrosion and could boil giving a squishy pedal.
I did some research when looking into getting a performance fluid, and keeping the system regularly bled with fresh fluid is very important if you don't want your fluid to boil under heavy use, no matter what the fluid.

Hope this helps... and hopefully its fact too!

[jeremy fisher]

I think I got DOT5 and DOT5.1 mixed up! Whoops!

[Gareth_C]

Sounds like some good advice cheers I believe you get what you pay for and my local motor factors sells carplan crap I'll try the mintex and see what it's like

[Graeme]

I use Ate super blue from Euro only so I could tell when the fresh fluid was coming through, seems ok so far?

[Stuart]

I use Ate super blue from Euro only so I could tell when the fresh fluid was coming through, seems ok so far?

It will stain the lines and make bleeding with the amber fluid a nightmare.... I loved the performance of sper blue but hated the stained lines. Mintex 5.1 was as good IMHO