While reading a Land Rover magazine I came across an ad for Defender-fit LED rear lights. Now I know the Cobra brake lamp is the same size, marked Lucas L760/L874. The company is Boltonbits and they trade via an Ebay store. I rang them up and they confirmed it was the same size as the Lucas lamp, and that they could supply a stop/tail lamp (2w/21w) with a clear lens and red LEDs. £21.49 and 2 days later it arrived.
It is a fully sealed unit (IPX rated), CE marked and with a nice neoprene gasket. It has a complex refelector, and 4 LEDs which all light up. The wiring determines the wattage: black = ground, red = tail (1w) and green = stop (4w). The 4w setting was very bright indeed when I tested it on a 12v power supply.
Taking the lens off the Cobra reveals the 21w bulb and bulbholder. This is removed by unscrewing the two screws at 12 and 6 o'clock. Behind are two wires: black (ground) and purple/green (brake). I simply cut these and connected to the LED unit black and green wires. I used the original screws to secure the LED unit, compressing the gasket. It worked immediately.
The whole job took 15 minutes including photos, and I think it looks rather nice - see next post!
I'm very happy with this. It's really bright when lit, and comes on instantly, unlike the ordinary bulb. This has to be a safety advantage. Also I think the clear lens makes the Cobra much less intrusive visually.
The other lights are a completely different Lucas fitting from the Cobra, and have a larger diameter lens. I'm wondering now if I could get the land rover size LED units *inside* the other rear lights...I'll take one apart and measure.
An excellent upgrade, not sure yet, but they look very similar to S1 rear light fittings. Will have a close look next week.
They are smaller than Aero light fittings. The Aero lamps are the same as recent trad front lamps (77mm diam). Boltonbits do have a Wipac LED unit at 75mm that may substitute for those.