Bleeding The Brakes
If you do any work on the brakes you should consider bleeding them.
Mod difficulty:
Mod Credit: Matt

Thanks to Matt from the Evilution forum for the info on the DIY bleeding.

Warning
Brake fluid is dangerous, acidic, poisonous and potentially lethal. Be careful.
Bleeding The Brakes The DIY Way
 2 Man Job

Firstly, remove the brake fluid container cap. This allows air to be drawn into the top of the tank otherwise a vacuum can forum causing air to be drawn into the bleed nipples.
Connect the bleed pipe to the nipple on the caliper/drum cylinder.


 Any 3mm I/D hose should be sufficient but clear tube is best as it
 allows you to see any bubbles being pushed from the system.


Open the nipple a quarter to half a turn.

Have a person in the cabin press down hard and quickly on the brake pedal, all the way to the floor and then hold it there. Doing it quickly pushes out the air bubbles and stops air pockets remaining while reducing the possibilty of air re-entering the system.

When fluid stops coming out from the first push of the brake pedal, retighten the bleed nipple. Have the person in the cabin slowly raise the brake pedal.

Doing it slowly prevents air bubbles being drawn into the system.

Re-open the bleed nipple so the brake pedal can be pressed again.
 Continue until a clear and bubble free stream of brake fluid is ejected from the bleed pipe.

Check the level of brake fluid in the brake fluid reservoir every 2 pumps or so,
 to ensure that it doesn't empty - if it does air will be drawn into the system
 and you'll have to start all over again.

Repeat with all four brakes, Ideally the system should be bled from the
 furthest point to the nearest so follow this pattern:

offside rear
nearside rear
offside front
nearside front

The Easy Bleed Way
1 Man Job

An Easy Bleed pump is attached to the brake fluid tank and pumped to apply a pressure.
The pump contains brake fluid so as the brake bleed nipples are opened,
the pressure helps push the fluid through slowly but at the same time
refils the expansion tank so it doesn't run low. The system should be
bled from the furthest point to the nearest so follow this pattern:

offside rear
nearside rear
offside front
nearside front

According to Matt this isn't as effective at flushing air bubbles through the system.
I can understand why as the process was very slow so may not push the air out.

The Check Valve Way
1 Man Job

These fluid check valve bleeders are usually used on motorbikes and can be bought from
Halfords and eBay. The kit consists of 2 clear pipes and the valve. The valve has an arrow
that shows the flow of the fluid. The arrow should face away from the bleed nipple.



Put the hose over the nipple, put the tube clamp on and put the other end into an empty bottle.



Open the bleed nipple 1/4 turn and start pumping the brakes.
Keep an eye on the brake fluid level, don't let it get too low.
10 or so pumps should be enough, tighten the nipple back up again.

Check Valve Bleed Nipples
1 Man Job

These are common upgrades on motorbikes. It's a similar setup to the check valve method shown
above but the valve is inside the bleed nipple so you just need to fit these and use a plain hose.



Here is a CVBN fitted to a standard smart caliper.



Fit a clear hose onto the nipple and place the other end into an empty bottle.



Open the bleed nipple 1/4 turn and start pumping the brakes.
Keep an eye on the brake fluid level, don't let it get too low.
10 or so pumps should be enough, tighten the nipple back up again.



Check Valve Bleed Nipples (CVBN) can be bought from SmartMods.co.uk
They aren't on the site, you'll have to contact them directly.

All Done?

If you are sure the lines are tight and not leaking, the brake fluid isn't low and the bleed
nipples are tight. It is time to refit the tank cap, reassemble the car and try them out.
Before you move off, pump the brake a few times to make sure it builds up pressure.
If it feels spongy it will be trapped air in one of the brake lines.

If the pedal feels firm after a few presses go for a slow drive and test them out.

Additional Info

Thanks to Paul about the info on DOT 5.

This process won't change the fluid in the ABS pump - a dealer needs to connect the car up to their system to do this, which will open the valves in the controller to allow fluid to be flushed through.

DOT 3, DOT 4, DOT 5, DOT 5.1?

The brake fluid DOT (Department Of Transportation) is a set of specifications that brake fluids have to adhere by to get a particular number. It tells you its composition and what temperatures it can deal with.

DOT 3

Oil and glycol based.
DOT 3 can handle Dry boiling point 205°C, Wet boiling point 140°C.

DOT 4 (smart standard)

Oil and glycol based. Compatable with DOT 3 and DOT 5.1
DOT 4 can handle Dry boiling point 230°C, Wet boiling point 155°C.

DOT 5

Silicone based. NOT compatable with any other types of brake fluid.
DOT 5 can handle Dry boiling point 260°C, Wet boiling point 180°C.
Silicone fluids do not absord water from the air like the others.

Some people talk about upgrading to DOT 5 brake fluid when fitting braided hoses.
This silicon based fluid is incompatible with the smart braking system, it has a tendancy
of breaking down the caliper seals causing leaks and brake problems.

DOT 5.1

Oil and glycol based. Compatable with DOT 3 and DOT 4
DOT 5.1 can handle Dry boiling point 270°C, Wet boiling point 191°C.

Er, Good, So Which One Do I Get?

Smart recommend  MB 331.0 brake fluid which is part number  000 989 08 07
although almost any DOT 4 will work perfectly in all smarts.
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