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Servicing guides and mods

Windscreen Wiper Replacement

Wipers should be replaced every year but it's amazing how many people don't and also don't know how. This will take you through a few options.

Modification Details

600cc And 700cc Smart Wipers

Windscreen wipers haven't changed much since they were first made,
they are still a length of rubber that is dragged across the windscreen.

What has changed is the rubber, the shape and the construction.

Here I will tell you about 5 options.

Standard Bosch replacements
Larger replacements with spoilers
Bosch Aerotwin
PIAA silicone

450 & Roadster Wiper Removal

Here are the standard wipers found on the smart, they are 21' long.

All that holds them in place is a metal hook and a plastic insert.

Fold the wiper arms away from the windscreen,
Turn the wiper 90 degrees from the wiper arm.

Squeeze the back of the plastic clip...

and pull the wiper towards the base of the wiper to free it from the hook.

If you are replacing your wipers with anything that Halford's sells, follow this part.

With both of the wipers off of the car...

Remove the plastic insert by spreading it apart...

and sliding it off of the spindle on the old wiper. Replace the clip onto the new wiper blade
and refit to the car in the reverse order of what's shown above.

451 Wiper Removal

Fold the wiper arm away from the windscreen and look at the fitting.
On the wiper you will see two clips, one on each side. Press these both in.

With them pressed in the wiper frame can be tilted away from the arm slightly.

Once the clips are free, the wiper can be slid off the end of the arm.


As usual, fitting is the reverse of above but be careful not to clip the wiper over the arm.
As it slides in place it can latch over the end of the arm causing it not to slide.
Just pull the wiper off again and try once more.

Larger Replacements With Spoilers

If however, you purchase a set of 22' wipers with a spoiler they
come with a dual way adapter to aid fitment to many cars.
If you look at the adapter you will see each end marked either 9x4 or 8x3.
The smart fitment is the 9x4 side of the adapter so make sure the is the side you use.

Clip the 9x4 side into the new wiper blade...

and slide it around and into the wiper arm hook...

until it is fully seated in the hook.

Repeat with the other side and fold the arms back onto the windscreen.

Even though the replacement blades are 22' instead of 21', there is still
plenty of room between the 2 as they move meaning they won't clash.
But they will sweep more of the screen which means a better view.

These Motoy wipers also come with attached spoilers, they aren't there for decoration.
The spoiler keeps the wiper on the screen at high speed as the smart wipers are prone to
lifting causing a judder or catching on the screen, this limits the effectiveness of the wiper.

Bosch Aerotwin Wipers

These are the new wave of aerodynamic wipers fom Bosch. They have become common
fitment on many new cars and look better than the original frame design of old.

Up until recently there was no way to retrofit these wipers as the wiper arms
have a special attachment as opposed to the hook on standard wiper arms.
Bosch have invented a system that allows the fixing to most other cars.

Here are the wipers as I bought them from my local motor factors for £17,
they are Bosch Aerotwin AR 530 S which contain a pair of 21' blades.

Instead of having a metal frame they are constructed over a pre-bent flexible metal strip.
The rubber blade, spoiler and clip are attached to surround the metal.

This close up shows the new design clip. Pressing the tabs either side allows the
top part of the clip to swing up allowing access to the insert.

You can see the familiar looking insert inside.

With the flap up, it is ready to be fitted to the car.

Remove your old wipers and push one arm through the hole in the clip.

Rest the arm on top of the insert and pull.

The hook will grab the insert like a normal wiper.

Fold the clip back down to secure.

Repeat with the other wiper arm.

This shows the cross section of the Aerotwin wipers, you can clearly see the built in spoiler
that increases down force onto the screen. There is one issue with the AR 530 S.

This particular set is designed for a some Audi, Renault, VW and Volvo cars.
These have 2 arms that pivot from the offside of the car, the smart has a pivot on both sides.
The problem is that the Aerotwin wipers are 'handed' meaning that in this particular application,
the upper wiper is positioned with the spoiler facing backwards instead of forwards.
The nearside wiper will not benefit from the down force because of this.

Bosch eventually started selling universal flat blade wipers in different lengths that had a multi clip
design that could fit onto almost any car. This means you can mix and match to suit your car.

Aerotwin Codes

Smart Fortwo 450 - A992S
Roadster RHD - AR502S
Roadster LHD - A502S


Go to eBay and type in the following details.
Wiper lengths (21 22 etc)
Wiper fitment (hook or multi)
Bosch flat.

For example, for the 451

21 22 multi bosch flat

and and example for the Roadster

18 20 hook bosch flat

Hook Or Multi Fitment?

Fortwo 450, Roadster and Forfour require hook fitments.
Fortwo 451 requires multi fitment.


fortwo 451

AM21U - 21" with multi clip fitment
AM22U - 22" with multi clip fitment

Michelak Frameless Wipers

Years before Bosch created the fitment shown above, Michelak devised
a way to modify the original Bosch frameless wipers to fit the smart.

A metal bar was attached into the side of the wipers which clipped into the J hook inserts.

The confusing part is that although the Bosch blades shown above are
very good and the fitment of the Michelak conversion was very clever,
their ability to wipe the screen was total rubbish.

They retailed for nearly twice the price of the Aerotwin blades and so many people tried them and were disappointed that they quickly fell out of favour with the smart crowd.

PIAA Silicone Wipers

Back to the old tried and tested frame design of wipers but with an update on the blade.
Instead of using rubber, PIAA have opted for silicone. A few companies boast silicone blades but all of them are just silicone coated rubber.

Silicone has many key properties that make an excellent wiper.

will not perish or degrade
resistant to chemicals
resistant to hot and cold
treats the windscreen on each pass

The chemical composition of the silicone wiper blade applies a fine layer of silicone to the screen.
This causes beading of the water much like the effect when you use Rain-X.

The wipers are far more expensive but they do an excellent job of clearing the screen.
Over certain speeds, there are times you don't even need the wipers going as
the water beads and runs off the screen with the flow of the air across the car.

Visually the PIAA wipers look the same as standard wipers and fit the same way too.

What Length Wipers Do I Need?

That info is covered here.

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