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How much brake fluid to flush system?
johnH20 - 1/11/13 at 10:20 PM

I need to replace my brake fluid. How much do I need to flush the system and replace?
Supplies seem to come in 500 ml bottles, is this the right amount? TIA

Slimy38 - 1/11/13 at 10:29 PM

It's going to be entirely dependent on your car, as well as how much fluid you use up during bleeding? Personally I'd aim for between 1 and 2 litres, if you don't use all the fluid you can keep the bottles sealed.

You might already know this, but it is much harder to bleed a drained system than simply to run clean stuff through. I know several friends who regret their decision to empty their brakes and the subsequent hours/days of trying to get the new stuff in. Just wanted to mention it...

coyoteboy - 2/11/13 at 12:34 AM

Just shy of a litre to bleed my mid sized tin top with ABS. Halfords 1 litre bottles of 5.1 work a treat.

snapper - 2/11/13 at 08:53 AM

Yep, I'll go with a Litre, tried with a 500ml bottle and had to go out for more
As always start with closest run from master cylinder and work further away.
I found getting the fluid to run clear can take a few goes.

Slimy38 - 2/11/13 at 09:51 AM

quote:
Originally posted by coyoteboy
Just shy of a litre to bleed my mid sized tin top with ABS. Halfords 1 litre bottles of 5.1 work a treat.


Mmm, I wonder if I needed more because it has a hydraulic clutch off the same reservoir? Or I'm just really bad at bleeding brakes!

britishtrident - 2/11/13 at 10:07 AM

(1) Push the calliper pistons back.
(2) Empty the reservoir with a Turkey baster.
(3) Fill reservoir with fresh fluid.
(4) Bleed fresh fluid through to the caliper.
(5) Top up and before driving pump the pedal hard to push the pads in contact with the disc.

500 ml of fluid should be enough.

coyoteboy - 2/11/13 at 11:36 AM

quote:
Originally posted by snapper
Yep, I'll go with a Litre, tried with a 500ml bottle and had to go out for more
As always start with closest run from master cylinder and work further away.
I found getting the fluid to run clear can take a few goes.


Accepted wisdom is to bleed furthest first unless instructed otherwise by the manufacturer.

adithorp - 2/11/13 at 11:49 AM

quote:
Originally posted by britishtrident
(1) Push the calliper pistons back.
(2) Empty the reservoir with a Turkey baster.
(3) Fill reservoir with fresh fluid.
(4) Bleed fresh fluid through to the caliper.
(5) Top up and before driving pump the pedal hard to push the pads in contact with the disc.

500 ml of fluid should be enough.


I'd add when doing "1" either empty the res (2) first or it'll overflow. Alternativly open the caliper bleeder before pushing back to empty the fluid through the bleed nipple instead of pushing it back to the master/res.

General rule is to start with the furthest and work back. You should be able to see the change in colour when the fresh fluid comes through. If you can't it didn't need changing.

coyoteboy - 2/11/13 at 01:36 PM

Shouldn't need to do 2 first unless you strangely top up to account for pad wear?! The res should hold enough to take Max wear on all pads before passing the min mark.