Retrofit Retrofit
Car: Mercedes-Benz | CLK | W209 | Avantgarde | Coupe
Engine: CDi | 0 | Inline 5 | (170 BHP) | Turbocharged | Diesel

C/CLK Sport/AMG Brake Retrofit


The majority of non-V8 W209 CLK's and W203 C Class cars come with 288mm or 300mm front discs and cast iron single piston sliding calipers (right), which in my opinion are marginal for the weight of these vehicles, especially the larger diesel and 6 cylinder petrol models. A simple upgrade is to move to the W203/W209 Sport Package brakes, or even AMG versions.

Upgrade options

This article concerns the front brakes as the CLK comes with at least 290mm rear discs which provide adequate balance for even the 350mm front package. C Class often has 278mm which is an adequate match for the 330mm front upgrade.

Front: 2 piston, 330mm | Rear: 2 piston, 290mm

w209sportbrakes w209sportbrakes

2 opposed piston calipers constructed of Aluminium. These are typically grey with 'Mercedes-Benz' lettering on the outside face between two large external Torx bolt heads. Discs are 330mm and perforated.

This package is fitted to Sport Package vehicles. 17" wheels required.

Front: 4 piston, 345mm | Rear: 2 piston, 300mm

w209sportbrakes w209sportbrakes

4 opposed piston calipers constructed of Aluminium. Silver in colour with black '/////AMG' lettering (CLK55), or plain grey. Four external type Torx bolt heads on front face. Discs are 345mm and perforated.

These are fitted to 2002-2004 CLK55 and large capacity models (350, 320 CDi). 17" wheels required.

Front: 4 piston, 350mm | Rear: 2 Piston, 300mm

w209sportbrakes w209sportbrakes

4 opposed piston calipers constructed of Aluminium. Grey in colour, outside face has two external Torx bolt heads with a raised ridge running beween them. Discs are 350mm and perforated. Identify these by their shape, which suggests 2 pistons per side.

Thiese are fitted to late, large-capacity CLK models. 18" wheels required.

Front: 6 piston, 360mm | Rear: 4 piston


Late CLK55 AMG calipers moved up to 6 pistons front and 4 pistons rear and are again of 'Monobloc' Aluminium construction. The cost of these is way in excess of the two options mentioned above, and retrofitting of these generally requires a change of mater cylinder to support the additional fluid volume in the calipers. Discs are composite 360mm (front) and require 18" wheels.

Braking Bias

Mercedes fit a different brake balance valve A 005 430 99 01 to Sport Package vehicles. The valve allows slightly more brake pressure to the rear in order to provide better braking feel, but is entirely optional when retrofitting 330mm or 345mm front brakes with 290mm rears (or 330mm front and 278mm rear).

Please always use common sense when choosing brake upgrades and keep front/rear disc sizes proportional.

Retrofit Sport Package or 4 piston AMG brakes


My CLK is the 270CDi model and therefore I did not need not out-and-out braking performance, just a useful increase in power. With this in mind I chose to fit the Sport package brakes, but note the procedure for fitting any of the other options would be identical.

I used eBay to find a set of brakes (right); the calipers came from the US and the discs in the UK.

Mercedes are often keen to recommend early disc replacements and due to this second-hand sets with good life remaining do appear on eBay, I paid £30 including delivery for my discs and a further £30 to have them resurfaced. The resurface or 'skim' left 1.5mm thicnkness remaining before the wear limit which equates to approximately 15k miles of braking life.


I chose to paint the calipers Silver and add AMG decals (left). This is of course a matter of taste; I was adding the whole sport package at the same time.

Fitting is easy! Remove the wheels, 2 * 18mm bolts holding the caliper, the fluid hose, a T30 Torx screw holding the disc, and the disc itself. Reverse to fit using the new parts. Time required is approximately 1 hour for both sides, plus time to bleed once finished.

© Mark Stewart, Sunday 28th September 2008
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