[TR] TR3A Brake light switch

Randall TR3driver at ca.rr.com
Sun Sep 26 10:03:29 MDT 2010


> has anyone replaced these switches with a new one and did 
> the new one work
> with minimal pressure on the brake pedal as one would expect. 

It's been a few years now, but I had exactly the same problem.  The
replacement switch worked fine for a few months, then gradually started
taking more and more pressure.  That happened with switches from Moss, TRF,
and FLAPS.

> 2nd approach would be to bypass this switch with a brake 
> pedal mounted one
> like my TR6 brake switch.

That is the way I went.  The one I put on the TR3A worked great for several
years, but oddly enough I'm having trouble with the one on the TR3.

Apparently, silicone brake fluid is the kiss of death for switches.  I use
DOT 5 of course, and had a leak on the TR3 that allowed it to slowly run
down the brake pedal.  When I disassembled the nearly new switch, it was wet
inside with what appeared to be DOT 5, and one of the contacts was covered
with a hard black substance that did not conduct.  Likely it was burnt brake
fluid.

FWIW, here's a shot of the new brake switch & the bracket I fabricated, to
mount it under the dash out of sight.  Just a piece of flat steel bar from
Home Depot, bent at an angle, and ground/drilled to suit.
http://tinyurl.com/2efyus7

No doubt you'll want to do a nicer job, but I was in a hurry.  And since it
is out of sight (unless you have your head in the footwell), it doesn't
bother me <g>  Maybe someday, after I retire and get bored without enough to
do, I'll pull it back apart and powder coat everything.

Randall


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