rear brake light switch

Bike failed its MOT because the brake light doesn't come on with the rear brake. The switch works, but needs (quite a lot of) adjustment. Unfortunately this has not been done for a while, and the adjuster doesn't move on the switch, turning it just moves the whole switch. cos of where it is placed I cannot get any purchase on it, any tricks of the trade? or do I just keep spraying it with WD40 and hope It loosens eventually.

[Bibio]

there should be a big plastic nut that you turn instead of turning the actual switch body. first check that the spring is not rusted and stretched and if it is replace the spring. while your there grease the linkage (cleat nut and lever pin).

Yeah, the adjuster. But when I turn that, the whole switch body turns with it because the switch body thread is quite grimy. I can't get enough purchase on both at the same time to break the seal.

The spring doesn't look too stretched, which is surprising since its about 15 years old, fairly corroded, but no rust.

[jambo]

Take the peg assembly off using the 2x 6mm hex bolts.

This should give you more access.

Jambo

Yeah I have to do that just to get into the nut in the first place, I can get a hand in, or just about get a normal spanner in, but that's really about it.

[Bibio]

take the spring off and then pop the switch out of its holder, you can then turn the big nut easier. or just spray some chain lube on the big nut and holder then turn.

So the switch and adjust should just come out the holder? Didn't seem to want to budge but will go try it again.

sorted, thanks guys. Gave it another go, and realised that I was just pushing it up into the wire cluster up there. Moved that away and jiggled it about a bit and Robert's your father's brother. Didn't want to push it too hard before in case I was asking it to do something it wasn't supposed to.