Brake Fluid Level

Mod Description
Brakes are pretty damn important and you tend to use them heavily in dangerous situations so it's nice to know they work.
Mod Details
PremiumNo Difficulty Mod ID163 CreditEvilution Cost££0 For450 Fortwo451 Fortwo452 Roadster Linkhttps://dev.evilution.co.uk/mod/brake-fluid-level.htm Copy to Clipboard
450 Fortwo

Stand facing the front of the car and to the left you will see the service screen.
Circled in red is the latch.

Twist it ¼ turn clockwise with a screwdriver and pull the plastic screen away from the car.

Looking down the hole you will see the brake fluid container (circled yellow).

This has the min/max markings on the side nearest the front so levels can be seen easily.

If the fluid is below minimum you should top the level up to mid way . The smart manual doesn’t specify a type as they want to charge you so they can do it.

What ever you do don’t get any on yourself, the Tridion or the panels of your car, it’s really nasty stuff and highly corrosive.

Total Brake Fluid Capacity – 0.5L


451 Fortwo

First thing to do is access the fluids of the new smart by opening the bonnet.

Look over to the left and you will see the brake fluid container.

Open the container by unscrewing the cap, you will see the min/max mark inside. If the fluid is below the minimum mark, top it up to mid way.

If you are topping up the brake fluid, don’t get any on yourself, the tridion or the panels of your car, it’s really nasty stuff and highly corrosive.

Total Brake Fluid Capacity – 0.5L


452 Roadster

Thanks to Gavin of www.onsmart.co.uk for the use of his Roadster.Open the bonnet and remove the liner by following this information. Look to the back of the bulkhead and you will see the brake fluid tank. Twist the top off to view the contents and the level of the fluid can be seen on the side.

Top the fluid up if it is looking low, again, be careful as brake fluid is nasty stuff.

Total Brake Fluid Capacity – 0.5L


453 Fortwo & 453 Forfour

Open the bonnet and look for the black cap with DOT 4 written on it, that’s the brake fluid reservoir.

The minimum and maximum is marked on the side.


Additional Information

Edited and added to information sent by Keith.

Although brake fluid is not consumed during normal driving, the level will reduce.
This is because the brake pads and shoes wear causing the caliper pistons to move further out, therefore taking up extra brake fluid. If your brake fluid is below the minimum mark you should check the thickness of the pads and shoes to ensure they aren’t worn excessively.

The smart does not have visual brake wear sensors, it will not tell you when the pads need changing.
The front brake pads have audible sensors that make a screech noise when they are low and you brake.

If your brake pads and shoes are ok but the fluid is low, top it up to the mid way point between min and max to make sure that no air can get into the system. Have the brake system checked for leaks.

If you do any work on your brakes and you have to bleed the system, keep the tank topped up.

If you have a Refractometer, check the water content of the brake fluid and change accordingly.
This of course is very unlikely, there are cheaper fluid testers but a good garage will perform a reliable test for you for very little money. The recommended change duration for brake fluid is 2 years but it is an extra charge from smart, they will not perform this unless you instruct them to.

Why Change Brake Fluid?

Standard brake fluid is hydroscopic, this means it actively absorbs water from anything it can.Water will reduce the boiling point of the brake fluid to the point where the heat from the calipers will boil the fluid in the pipes. When the fluid boils, the water creates
gas. Gasses can be compressed unlike fluid.

As gas forms in the brake system the brakes become less effective and the pedal can feel spongey.
Eventually the pedal will travel all the way to the floor and very little braking will occur.

This is the point where you crash. Remember, the brakes are the most important thing on your car.

Recommended Brake Fluid

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