Footwell Corrosion

Issue

Footwell corrosion is an issue which can affect S1 and early S2 Elises fitted with the bonded down rubber floor mats.

Rubber floor mat fitted on the drivers side of an S1 Elise, note the footwell centre divider has been removed for ease of access.

The non-breathable rubber floor mats can cause moisture and salts to become trapped against the floor which can then react with and corrode the aluminium floor.

The severity of this reaction can vary, from minor cosmetic marking of the floor to pitting, or at worse corroding through the floor panel.

Although this may sound bad, and while the floor panel is bonded in as part of the aluminium chassis around which the Elise is based, the floor panel itself is not a load bearing panel and even heavy corrosion can be repaired without necessitating a replacement chassis.

Mat Removal

If your car is fitted with the rubber footwell mats it is strongly recommended to remove them immediately so that the floor condition can be assessed.

The mat is attached with adhesive around the outside edge. If possible find a loose edge and use this to pull the floor mat up, or use a Stanley knife to cut the mat in the centre - although if doing this be careful not to score the floor underneath. Do not try and lever the mat up against the kick plate at the front edge as a screwdriver or similar will mark the soft aluminium of the kick plate.

Rubber floor mat fitted on the drivers side of an S1 Elise, note the footwell centre divider has been removed for ease of access.

With the mats removed peel up any remaining rubber still attached to the floor and hoover out any dirt, debris and surface corrosion.

Treatment

The action to take will depend on the severity of the corrosion to the floor. If the floor has corroded to the point where holes have appeared in the surface then the best course of action is to fit secondary floor panels (Part No. A117A0235S).

If corrosion is minimal then apply a coating of ACF50 to inhibit corrosion and fit breathable fabric floor mats. Be sure to lift the floor mats regularly to clean and wipe up any moisture and reapply the ACF50 every 12 to 18 months.

You may wish to rub down the floor with Scotch Brite Pads to remove any sharp edges and to reduce the visible surface corrosion. If doing this be sure to wear a face mask as a considerable amount of dust will be created. After sanding and cleaning the floor either spray it with ACF50 to inhibit corrosion or paint using silver POR15 to match the aluminium chassis.

Links

http://forums.seloc.org/viewthread.php?tid=318085 http://hazelnet.org/corrosion/index.htm