Elise Chassis Corrosion.
We look after many hundreds of Elise's and their derivatives, over the past few years we have noticed a powdery deposit associated with aluminium oxide corrosion around the front upper wishbone mounting point which understandably has given us some cause for concern.
Recently we have had an Elise in for some suspension work which has given us the opportunity to remove the front upper wishbone. Having removed the wishbone we found that the area that had been concerning us had corroded to the point that it was perforated around two thirds of the way round the mounting point.
We
have investigated the cause of the aluminium oxide corrosion and
have come to the conclusion that it is as a result of the chemical
reaction between the chassis bobbins (the thick washers that are bonded to
the chassis), mild steel caster adjustment shims and the aluminium
chassis, this problem is exacerbated with natural build up of road
muck around this area.
At this stage It is likely there are only a few
early high mileage cars that have corroded to a point where the
chassis is perforated. On the rest of them the important thing is to
stem the corrosion. With this mind we are currently having the
caster shims produced in an material that will not rust and so
reduce the chemical reaction between the chassis bobbins and the
aluminium
chassis. We will need to remove the top wish bones, clean and treat
the chassis bobbins and the chassis, paint the affected area and
reassembled with our new caster shims, this will stop the corrosion
in its tracks and greatly reduce the chances of it reoccurring.
For cars where the corrosion has perforated the chassis we are working on a repair panel that we will be able to bond and rivet into place to regain the original strength.(Watch this space) Although we would discourage any owner from this form of repair until the manufacturer has had time to evaluate the problem and perhaps come up with an official repair.
The
same chassis bobbins and caster shims are still being used by Lotus
on the current Elise's and the derivatives, so even the current cars
will in time go the same way unless the chassis bobbins are treated
and the shims car changed.
We are offering a free visual inspection for any owners who may think their vehicle may be affected please ring 01932 340003 to arrange an appointment.