Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Changing brake fluid 2010 Roadster

Those switches can be a bit short lived..... The repeated arcing across the contacts degrades the switch. As time goes by you need more and more pressure to operate the switch so the brake lights become less responsive. No I don’t think the relay came as standard and yes adding a relay significantly reduces any contact arcing.

Thanks Rog, mystery solved 😁

Roadsters of that era left the factory with the old style hydraulic pressure switch, these tended to fail because of the crap quality of switches (not MMC's fault almost all the current makes are rubbish) the longest lasting I've found are Intermotor brand.

Lot's of owners added a simple relay to reduce the load the switch contacts take & this generally works well, but worth carrying a spare hydraulic sw if you're doing long tours, as they can be changed roadside without needing to bleed the brakes if you are confident & don't dawdle with the spanner

Mine was replaced a couple of years ago cos the previous owner replaced it with a one that didn't have a tapered thread, and this apparently cracked the union. Guess I'd better get a spare.

Fit a relay and a microswitch on the pedal. It's a simple mod and solves the problem.

For the hydraulic pressure switch I used one of these
https://www.goodridge.co.uk/products/brake-light-switch-metric-single-banjo-bolt
to replace the banjo bolt on the master cylinder. Much neater.
Also used one on the clutch cylinder for the drive safety lockout on startup.

Relays have their place but would favour a quality hydraulic or direct pedal operated switch, underrated current wise for the task. The extra wiring and possibly poor location of relay adds complexity and potential unreliability.

Note also having LED brake lights as well as generally being brighter puts far less current load on switch.

I'm not that confident in wiring in a microswitch. I take it from what you say that there's no reason why I can't just swap my bulbs for led ones?

Just ordered 3 replacement led bulbs from classic car leds. Bet they outlast the car 😂

Yes, I went down that route eventually, if you fit a decent plunger switch rated at least 5 amps you don't even need the complexity of a relay