So my 1963 f100 4x4 has been my work in progress over the last 3 years or so. About 2 years ago I completely rebuilt the brake system, rebuilt wheel and master cylinder as well as replaced the lines and even replaced the brake switch. All was well until about a month ago when my dad called me at college to tell me he took the truck out and the brakes failed.

I figured it was a wheel cylinder that came apart or a loose fitting or something of that nature. When I got home I checked all the wheels and connections and didn't spot any leaks. I pressed the brake and it went strait to the floor and made a slight hissing noise from under the hood. I popped the hood and had my brother press the brake and fluid started squirting out of the brake light switch.

I bought a new brake light switch and bled the lines with some fresh brake fluid and everything works again. My main question is how can i prevent this from happening again. I live on a ranch, so when the brakes failed on my dad there was no real danger, but if I'm cruising at 60 down the freeway and the brakes go moosh, its not a good day.

The switch leaked on the top of the switch between the plastic and the metal.

 

This why its imperitive to have a well adjusted emergency brake...Its not just for parking...
As to the switch...just keep spares around along with tools to swap it out on the road....yes you would have air in the system after a roadside switch swap...but pumping alot would be better then getting no pedal...This is also why its better to have a manual transmission...more control in slowing down if the clutch is used properly.


- cs65

 

^^^^^Good suggestion by cs65. However, most everyone here on FTE that has swapped to dual master cylinder setup has just eliminated that fitting. You can still get rid of it with your single M/C.

Do a 'brake light switch' search and you will find an answer. Then, plug the old hole in the M/C!

 

Do what Greg said and plug the hole where the pressure switch goes. Pull the 2 wires back into the cab and by a switch for a '76. You have to be a little creative, but you can find a way to mount it and make it operate off your brake pedal.

Mark

 

Wow,,,, never heard of that,,, or had it happen,,,, I still run the single on both of my Slicks,,, have never had brake failure,,,, ever,,, that sounds like a fluke,,, or a china made pos,,,?

 

Before i did my disc conversion, i was warned by a few people that the switch can fail exactly in the manner described by the original poster.

 

Do yourself a favor and go to a dual master boosted set-up....it's a pretty cheap solution that adds a huge margin of safety.
Go to a wrecking yard and pull a booster/dual master from a 1968-79 truck...(even a new one is cheap)...if you find a decent one that
was recently on the road, the master may still be good. Remember, you have to bench-bleed it.

Look under the dash where the brake pedal mounts to the truck, behind it is a little button which turns on the brake lights...it
uses the same wiring the old one did....you just have to figure a way to mount the brake light switch button....very easy.
If you're running drums all around, then all that it'll need will be a few new lines....(pull the old ones from the donor).

The whole idea wit a dual master is that if you lose fr. or rear brakes, you still have the rears... there is no way to achieve that with
single masters. Your safety (as well as the rest of us sharing the roads) is worth the price.