brake light switch

[modified_studio2]

after having a motorcyclist warn me yesterday that my brake lights didnt seem to be working i have started to investigate what the problem is and i think Ive figured it out but throught id run it past you lot before purchasing parts.
The car is a 1966 mk1 and the problem is that the brake lights only seem to work when the pedal is pushed hard all the way down, under normal/light braking the lights dont operate at all. Im asuming the cause of this is a faulty brake light switch which is situated in the brake line on the front subframe.
Heres a link to the part http://minispares.com/Product.aspx?pid=36731

So does the problem im experiencing sound like faulty switch? and if so is replacing the switch easy? When i undo the switch will this cause brake fluid to leak out and will i have to bleed the system?
Thanks

[minimaniac]

It does sound like a faulty switch but before you buy one remove the wires from the switch and connect them together. The brake lights should work (with the ignition on). If they do it's the switch. If they don't then it's a wiring / fuse / earth/ bulb etc problem.

You will need to bleed the brakes if you change the switch but if you fill the master cylinder to the top and then put a plastic bag over the filler and screw the cap on (to block the vent in the cap) the amount of fluid lost should be minimal and a quick bleed should be all it needs.

[robileeson]

i had a similar problem on my 1992 city, not sure if its the same type of switch but on mine i loosened off the nut, and adjusted the switch accordingly until the brake lights came on when they were supposed to, and then tightened the nut again.

[Mk1Jim]

yeah not as easy as that on the older cars