S1 Braking System

Metal Matrix Composite

The MMC brakes work so well because the pad material transfers to the surface of the disc and forms a transition layer which provides the high friction between the pad and the disc. This transition layer is stable and remains at a constant thickness during normal use, as its wear rate is balanced by redeposition from the pads. If the brakes are subjected to extreme use the layer wears faster than it reforms and after a period of time the layer becomes so thin it loses its strength and can be plucked off the disc by the pads. When this happens the discs become scored and too rough to allow a new transition layer to reform properly. The only solution when this happens is to replace the discs and pads. The MMC discs were designed and specified for road use with the standard and VVC engined cars, with standard Pirelli tyres. Track use on stickier track tyres (such as the A038R) can allow the discs to get too hot. Cast iron discs and suitable pads are recommended for hard track use.

The MMC disks can also develop a film of condensation on them resulting in minimal braking effect on first application. The brakes can also get splashed from surface road water. A disk guard was introduced in January 1998 and fitted as standard from VIN 2260. It fits in-board of the disks and can be retro-fitted by a dealer. Earlier cars without a splash cover on the braking system will find that ingrained dirt can cause excessive wear to the disks.

Lotus had a deal with Lanxide to provide the first batch at a reasonable price, but after the first 2000+ cars were produced the real production costs were passed on to Lotus and these became too expensive to continue using them. There are rumours circulating that a licencing deal with Brembo was underway but the Lotus people that I've spoken to have said that it is no longer a possibility.

Cast Iron

Lotus are currently using Brembo brake pads on the Elise and some owners of newer cars have found the brakes to be poor. This is due to the varied compunds used on different cars. Mintex produce reasonably priced replacement pads and the hard road/race compound is recommended. Motobuild sell Mintex 1144 pads and they are £84 + VAT per set for front pads and £76 + VAT per rear set for rear pads. The Mintex part numbers are MDB1890 for the front set and MDB1891 for the rear set.

Iron disks corrode slowly when wet. If you've just driven in the wet then try and park the Elise with the hand brake off. If you've just washed it, then go for a drive to dry the brakes out. As the discs rust and slowly corrode, they will bind to the pads in a matter of hours. This doesn't do any damage but you will hear a clunk as they release, the first time you drive off. All cars do this but because the Elise is light, it's more noticable. It's also a good idea to let the disks cool a little before you park your car up with the handbrake on. As they cool, the disks contract and if you park on a slope with really hot brakes, the car may not be there when you get back. Don't wash the car just after a hard drive. If you put cold water on hot disks, they can crack.

Sprint Racing now sell 12 groove brake disks which are zinc plated and gold passivated to avoid unsightly corrosion on the hub and edge of the disk. They cost about £60 + VAT each.

Useful Information

• How to bleed brakes - A useful guide.