35 brake switch help

S

Solo_909

Senior Member
Hey fellas,

So my brake lights stopped working. I’m thinking it a the switch so I thought I’d make sure I get all the right stuff. When searching for brake light switches for a 35 ford coupe two different kinds show up.

This one

33zfl91.jpg


And this one

534w8w.jpg


Photo of my master

15d070i.jpg

2lasbvd.jpg


My brake cylinder uses the second one so has my 35 master been swapped with something else? If so with what?

Do I need to replace anything else besides the switch? What inside makes the switch work?

Thanks!
 
Yes its been swapped. Its hard to tell what MC you have going by the photos ,touch the two wires together that should activate the light
 
"My brake cylinder uses the second one so has my 35 master been swapped with something else? If so with what? "

1935 Fords were mechanical brakes, Ford didn't go to hydraulic brakes until 1939. Your brake system has been converted to a later hydraulic system. Some people like the hydraulic brake switch and some don't. The photos you posted show an original style mechanical brake switch (the repos are considered junk by some!) and a later (post 1939) hydraulic switch.
 
I've got to start digging into the same problem on my 35 PU this week. I have hydraulics, use Type 5 brake fluid and a Harley low pressure switch.


Rotts of Ruck with yours.
 
Solo_909 said:
What is a Harley low pressure switch?
Click to expand...

A Harley Davidson uses a hydraulic brake light switch essentially identical to the one you have pictured, but some say that the Harley switch is a lot better quality than the POS switches they sell at most auto parts stores, especially when using silicone (DOT 5) fluid. It's just a simple ON/OFF switch that closes the contacts when even low pressure is applied. DD
 
V8COOPMAN said:
A Harley Davidson uses a hydraulic brake light switch essentially identical to the one you have pictured, but some say that the Harley switch is a lot better quality than the POS switches they sell at most auto parts stores, especially when using silicone (DOT 5) fluid. It's just a simple ON/OFF switch that closes the contacts when even low pressure is applied. DD
Click to expand...

Thank you! I’ll stop by the Harley shop tomorrow!
 
Test the wiring first, remove both wires and add a jumper wire between both wires, you may have a blown fuse. If you have a multimeter you can also check for voltage going to the switch.
 
Side question,

Because the switch is vertical and not horizontal how do you get the air bubble out? I would assume air would get trapped in the switch when installing.
 
Solo_909 said:
Side question,

Because the switch is vertical and not horizontal how do you get the air bubble out? I would assume air would get trapped in the switch when installing.
Click to expand...


Not enough air to be concerned about.
Just change it out.
Be sure to get the Harley switch. In addition
to being impervious to DOT5 fluid, it takes less
pressure to activate. (at least mine does).
 
KGS said:
Not enough air to be concerned about.
Just change it out.
Be sure to get the Harley switch. In addition
to being impervious to DOT5 fluid, it takes less
pressure to activate. (at least mine does).
Click to expand...


Bought both the Harley and the cheap replacement. I take it the Harley is low pressure due to the smaller hole?

2q80r2h.jpg
 
The hole size has nothing to do with the pressure necessary to actuate. Kind of like 1/4" vs 3 /16" brake line won't show a difference in pressures. PSI is PSI, throughout a container system. That Harley switch is just designed with less pressure being necessary to make it work (,a lighter spring, probably). DD
 
Okay so everything works with the new Harley switch however there’s another issue that I noticed.

When I turn on the lights the tailights are lit up to the same brightness. When I turn them off and step on the pedal the driverside taillight doesn’t light up as bright as the passenger side. It’s really dim.

This also happened when I used the jump wire to test if the switch was bad. Any ideas about that?
 
Tail lights and brake lights are two different filaments in one bulb. Might try swapping the bulbs side to side, but it could more resistance in the brake wire on the one side. Do you have turn signals, if so that could be where the difference is coming from.
 
JSeery said:
Tail lights and brake lights are two different filaments in one bulb. Might try swapping the bulbs side to side, but it could more resistance in the brake wire on the one side. Do you have turn signals, if so that could be where the difference is coming from.
Click to expand...

Okay I’ll swap out the bulbs and go from there. This wasn’t an issue before the switch problem however I was messing around the the DS light a couple of weeks ago.
 
Solo_909 said:
Okay so everything works with the new Harley switch however there’s another issue that I noticed.

When I turn on the lights the tailights are lit up to the same brightness. When I turn them off and step on the pedal the driverside taillight doesn’t light up as bright as the passenger side. It’s really dim.

This also happened when I used the jump wire to test if the switch was bad. Any ideas about that?
Click to expand...

Try this.....since the driver side is the problem side, remove the red lens on the driver side light. Remove the bulb. Turn on the running lights. With a volt meter, determine WHICH of the two bulb contacts is hot. Now, turn the running lights off. Have someone step on the brake pedal. Use your meter to determine WHICH bulb contact is hot now. IF it's the same contact as before with the running lights, at least we know WHY it's messed-up, and we'll find out where the wires are crossed via troubleshooting. First, what are the results of your meter tests? DD
 
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