[T3] DOT5 and Brake Light Switches

[Sean Bartnik]

Hi everybody,
I just wanted to update the group on my ongoing experiment to try to find brake light switches that can hold up to DOT5 for more than a month. 

So far I've been through two new FTE brand switches (the $20 ones) and a NOS Ate switch, all of which failed in the same manner within a couple months. 

Previously while researching online I came across a Porsche 356 forum where a Harley-Davidson rear brake light switch was recommended. Turns out Harleys use the same type of pressure switches for the rear brake and they used DOT5 as factory fill brake fluid for a number of years, so  presumably their switches should be designed to stand up to DOT5.

About three months ago I installed an HD switch and it's been working perfectly ever since. No degradation of function; it still activates the lights with the slightest pedal pressure just as when I installed it. 

The switch is HD part number 72023-51E and costs about $20. The one I got was made in Italy by Bitron. 

The switch body itself is smaller than the VW switches but the threads are the same. 

This switch is a good option for early cars with the 2-prong switch. It would work for later cars too but you'd have to give up the brake warning light functionality because the Harley switch is a simple 2-prong switch. 

I hope I haven't jinxed myself by posting about it but it seems to be holding up well so far. Hope this helps somebody. 


-Sean