Brake Fluid Change

Post by **Dubstar** » 02 Oct 2008, 22:06

I'm thinking of dropping all the old brake fluid 'cos it must me 20 years and the pedal's not quite firm. I can bleed brakes no probs, but what's the technique for emptying the lot out and putting in fresh? Just open all the bleed nipples and pump away, then titghten them back up and bleed like normal? Any top tips welcome, even Viz ones!

Post by **rugchucker** » 02 Oct 2008, 22:28

I use one of those pressure ones that you connect to a spare tyre, then just crack open the bleed valve until clean fresh fluid appears. You can do the clutch at the same time.

Post by **Red Westie** » 03 Oct 2008, 14:03

Don't empty the system first, you will be making a simple job hard work!
Just Bleed from the furthest away first, then make you way to the closest, one at a time until each one bleeds clean fluid.
I think it helps to put just under half a litre through the first wheel cylinder (furthest away) and then as the main line will be filled with clean fluid you will only need a small amount bleeding from the remaining three (wheel cylinder and two calipers).
Also bleed from the clutch slave cylinder on the gearbox.
Will take from 1200-1500ml in total if you include the clutch.
Martin

Post by **Dubstar** » 03 Oct 2008, 22:00

Thanks for that guys. I've even got an Easi-bleed kit lying around somewhere so may give it a whirl. Amongst the many other chores I have this weekend! Dot 4 fluid?

Post by **Mark Foss** » 03 Oct 2008, 22:56

Yup Dot 4 Matey

Post by **dugcati** » 05 Oct 2008, 09:15

I use one of those pressure ones that you connect to a spare tyre, then just crack open the bleed valve until clean fresh fluid appears. You can do the clutch at the same tim.

I can totally reccomend the easibleed kits - after I re-did EVERY bit of brake line on my van I bled out the system (clutch lines too) by myself in around 15 minutes!

Post by **Rozzo** » 05 Oct 2008, 09:32

its easy to see when the new stuff gets through as the old fluid will be quite dark in comparison but as said before dont empty the system, keep it topped up all the time

Post by **Red Westie** » 06 Oct 2008, 10:25

Rozzo quote;
'Its easy to see when the new stuff gets through as the old fluid will be quite dark in comparison'
A common misconception.......and not always true.
The reason we change brake fluid is NOT because it is dirty but because it attracts and gets contaminated with water.
This means that the fluid can appear completely clean BUT still needs changing because of age/amount of water contamination.
For example; a vehicle that doesn't do many miles but hasn't had the brake fluid changed in 3-4 years (typical T25 in fact) where owners often don't use them every day.
This unusual property is call Hygroscopic (water contamination leads to a lower fluid boiling point and possible brake failure when the fluid starts boiling) this condition is called vapour lock.
Martin