Save that H. fr.brake switch ?

Torontonian · Nov 22, 2013

:idea: Anyone taken it apart to save the front hydraulic switch ? Looks encapsulated. Siezed. Unresponsive. Power good into both leads.

CanukNortonNut · Nov 22, 2013

Do a continuity check on the two terminal blades coming out of the switch. Squeeze the lever. If you get continuity when squeezed, then the switch should be good and now look elsewhere in the loom for your troubles.
CNN

Hobot · Nov 22, 2013

Don't think ya can repair the switch nor would want too if possible. Corrosion-blockage of passages or contacts likely failure mode that eats meat, so best wishes on attempt. BI vendors and Harley [same threads] have em but do note the type of terminals as some were round pegs for bullet connectors others flat blade type. Of course mastercyclinder must make proper pressure to function.

Torontonian · Nov 22, 2013

Not loom or connectors as touching both wires together at the switch produces rear brake light illumination so it is the encapsulated switch. Hydraulic pressure good. Have nothing to lose and 1" wrench in hand. End of season anways and will try wd 40 soak with some heat and rapping on wood. :idea:

Torontonian · Nov 22, 2013

Continuity check with brake lever pressure applied using pencil light at switch blade terminal a success ,so it must be old loom wiring and will work backwards towards tail-light. Thanks ,,now no need to attack switch. :|

Torontonian · Nov 23, 2013

New blade-type connector at switch cured the problem. Intermittent stuff so confusing. Switch functions perfect.

concours · Nov 23, 2013

Torontonian said:
New blade-type connector at switch cured the problem. Intermittent stuff so confusing. Switch functions perfect.

It will be back, they never "heal" themselves. Mine flaked out, I replaced it. For entertainment, I washed the sludge from the inside of the old one, it tested good. Then I binned it. Too much at stake (Buick enema)

jaydee75 · Nov 23, 2013

My bike sat for 25+ years with Dot3 corroding everything inside. During rebuild I removed the pressure switch and the pipe was clogged with crud. I cleaned it out and it started working again. I checked it on my air compressor, light comes on around 50 psi. Fine now.
Jaydee

Torontonian · Nov 23, 2013

Switch sill working well after 45 or so years ! Yay!

Pete_B · Nov 24, 2013

Thanks guys. This thread helped me to diagnose my problem. (No brake light when I apply the front brake on my '74
Commando). I performed the continuity check too. On the front brake switch terminals. However, the pencil light does not light up when I apply the front brake. So the brake switch must be toast. So, a question to you members who've replaced your front brake switches . . . will hydraulic fluid pour out when I unscrew the switch? Do I first need to bleed out the fluid?

toppy · Nov 24, 2013

If you leave the cap on you may not loose much fluid if you are realy lucky.
But YOU MUST BLEED THE SYSTEM AFTER ANYWAY so why bother drain it first an than you can take your time an not rush as you try to stop fluid coming out.

Hobot · Nov 24, 2013

You betcha fluid will go where ya really don't want it unless bled below the switch level. The switches I've dealt with were very tight so needed good space to get big wrench on and vice clamp the mc. This is the place telfon tape is meant for as anti-sezie as much as sealing ease, just don't let any swarf into the fluid section. Short cuts fettering a Commando don't usually work out well for me.

Biscuit · Nov 24, 2013

Oh no, not teflon tape, that's for plumming and pipe fittings. The copper sealing washer alone will do the trick. You can use a bit of anti-seize on the threads only but picture if you will a teeny thread of teflon making it's way through the brake line down to the caliper jamming itself in the equaly teeny caliper passages.

Torontonian · Nov 24, 2013

B-cool looking hippy -man thingy , the 1" wrench unscrewing of this switch will dump brake fluid. Corrosive paint eating stuffage.Teflon tape is for plumbings and pipes, not that application. Ain't the internet grand ? Flush-change brake fluid every 2 yrs.regardless. Hydroscopic. Water absorbtions = water =rust n' cruddy gew or whatevers. :| Get a haircut. Ha. What date photo ?

CanukNortonNut · Nov 24, 2013

Pete_B said:
Thanks guys. This thread helped me to diagnose my problem. (No brake light when I apply the front brake on my '74
Commando). I performed the continuity check too. On the front brake switch terminals. However, the pencil light does not light up when I apply the front brake. So the brake switch must be toast. So, a question to you members who've replaced your front brake switches . . . will hydraulic fluid pour out when I unscrew the switch? Do I first need to bleed out the fluid?

Pete_B
Well looking at where you hail from (frost is definitely on the pumpkin) I would say you have time to deal with the brake and components by changing all fluids and looking at the seals both at the M/C and the caliper. Buy new fluid for the next year riding season. If you still have the old 5/8 bore M/C, there are good improvements going to sleeving the M/C to 13 MM. This is a job for a Machinist if you buy the kit. Old Brits and Others Vendors have trades for the upgrade with no need to find a machinist. I would consider this a good investment to your Norton's braking ability and your well being in today’s traffic. You can purchase your hydraulic switch at the same time. Don't forget the aluminum washer under the switch if yours is pooched.
Cheers,
Thomas
CNN

Pete_B · Nov 25, 2013

Thanks for the great advice. Yep, that's what I'll do. Drain the brake fluid, replace the brake light switch, and send the master cylinder to someone for the for the 13"" re-bore treatment. (The photo is from 1974, on my first Norton. After parting with it -- one of the many dumb things I've done in my life -- I was incomplete until last year when I purchased a black one. I always wanted a black one anyway!)

concours · Nov 25, 2013

toppy said:
If you leave the cap on you may not loose much fluid if you are realy lucky.
But YOU MUST BLEED THE SYSTEM AFTER ANYWAY so why bother drain it first an than you can take your time an not rush as you try to stop fluid coming out.

JFWIW, I changed mine in a hotel parking lot with an 8" adjustable after having Old Britts drop ship to my intended destination. Lost less than a teaspoon of fluid. It's so near the master cyl, it self bled the air bubbles upward to the reservoir in 3 pumps. 5 minutes, no drama.

Save that H. fr.brake switch ?

Similar threads