[TR] DOT5 & brake pressure switch

[aribert neumann]

I don't have any knowledge of a TR3B   (I drove my Spit6 today, 50 mile
round trip, plan to do the same tomorrow).

I converted my '61 Ford Falcon to DOT5 about 25 yrs ago.  I have also
experienced the much shorter (hydraulic) switch life with DOT5.   I tap the
brakes prior to opening the garage door to check for brake light function
on any of my vehicles before departing home.   With the hydraulic brake
switch using DOT5, first the brake pedal displacement and then the braking
effort (to activate the brake lights) will increase as the switch begins to
fail.  I expect to replace the switch up to twice a year - I drive the car
8 months out of the year.   I am willing to replace switches rather than
cut into the harness.   I replace the switch without needing to do any
brake bleeding.

I buy a half dozen switches at a time from RockAuto.   The switch for my
Ford is Standard Parts SLS27, the switch has two round pins to engage the
harness.  In the past decade there is now a slip of paper in the switch box
warning me not to use DOT5.



------- Forwarded message ----------
From: Don Hiscock <don.hiscock at gmail.com>
To: Triumphs list <triumphs at autox.team.net>
Cc:
Bcc:
Date: Sun, 7 Sep 2025 20:08:21 -0600
Subject: [TR] "More reliable" sidescreen brake pressure switch for
DOT5/silicone?
I converted my TR3B to DOT5 three years ago.  I've been waiting for the
silicone oil to get into the pressure switch and cause it to quit working.
That time is here.

Yes, I could convert to a TR6 mechanical switch actuated by the brake pedal
lever.  I may end up there.  But it's fun to keep this car as original as I
can.  Is any one supplier's or source's brake pressure switch any more
reliable than the others around DOT5?

It was a nice day the other day, so the TR3B made the drive to the
village mailboxes now that I"m living in northern New Mexico.  Forty four
years last month that I've owned this thing.

https://photos.smugmug.com/photos/i-QRBNGvw/0/KvPKhzkvQRPj3kgscg4GSP4mLXMMpmfG2cqzZbBW4/X5/i-QRBNGvw-X5.jpg
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