Brake Fluid

[XK140]

Simple question,the answer to which I can't find either in the Heath book or via a search on here...
How much do I need for a complete fluid change?

[phillpot]

Depends how much you want to pump through to be sure all old stuff is out? Actual volume of the system is probably no more than perhaps 250ml/300ml (inc. reservoir) but it's not expensive stuff, I'd get at least a litre.


Might be less waste and "mixing" going on if you could syphon the majority of fluid out of the reservoir first?

[Alan461]

Half a litre should do it, pays to buy more than you need though

[phillpot]

Buy 2 x 500ml, then if you don't need second one it will keep better than a half empty (half full?) container.

[XK140]

2x500ml it is then, £2.27 x 2 from Euro Car Parts.
Same thing,1x 1 litre is £4.92...what?!!!

....and ,not unexpectedly, 500ml is £7.99 from Halfrauds!

Edited by XK140 on Monday 18th May 20:28

[magpies]

If you are changing then maybe best to use Dot 5.1 - higher boiling point and not much more expensive

[mk1fan]

There is a debate over whether DOT 4 or 5.1 is the best to use. I'm not going to enter into that debate or start it again here.

It comes down to cost and availability.

Like for like (ie basic Comma branded stuff) the 5.1 is better. I use the smae (basic) 5.1 on all my cars and bikes.

[Griffinr]

mk1fan said:

There is a debate over whether DOT 4 or 5.1 is the best to use. I'm not going to enter into that debate or start it again here.

A quick note of caution!

Since DOT 4 and 5.1 are both glycol-based brake fluids they are compatible with each other, which means they can be readily mixed without harming your brake system. It is important never to mistake DOT 5.1 (glycol-based) with DOT 5 which is silicone-based and should never be mixed with any other DOT fluid.

[XK140]

Since the car is road use only I've got the normal DOT4 stuff.

[Brummmie]

More dots does not mean better, boiling point is a good indication, the best race fluids are dot4.

[phillpot]

This DOT 4 / 5 thing seems a bit of a "minefield" ?

It appears many DOT 4's way exceed the minimum requirements.


While I reckon "any old DOT 4" would be more than adequate for my tootling around I might splash out on a bottle of this stuff next time round


Any one else old enough to remember the Crimson stuff, for drum brakes and clutches only, before these new fangled disc brakes came along?

[AutoAndy]

phillpot said:

Any one else old enough to remember the Crimson stuff, for drum brakes and clutches only, before these new fangled disc brakes came along? [/i]

.....no....I am old, but don't remember that...or dinosaurs ...

Sticking to 5.1.... More dots must be better as they are.....more...

[glenrobbo]

phillpot said:

Any one else old enough to remember the Crimson stuff, for drum brakes and clutches only, before these new fangled disc brakes came along?

I remember what happened if you topped up a Girling crimson system with Lockheed amber fluid:

All the seals turned to mush & generously lubricated all the brake shoes. Not good
The man with the red flag walking in front almost got run over!

No such worries with the good old rod-operated drum brakes on one of my previous runabouts.

Edited by glenrobbo on Tuesday 19th May 22:14