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Discussion Starter · #1 · (Edited)
Hi folks,

I have a 1966 mustang with front brakes swapped to CSRP kit (manual).

Having a problem with brake lights which began a month ago: brake lights turn on only when the brake pedal is fully pressed -- probably the last 5-10% of the pedal travel. The brakes work just fine, only brake lights are affected.

Details:
  • Replaced the bulbs. Confirmed tail lights work as well as turning signals.
  • Disconnected the connector from the brake switch and confirmed the wiring works fine: when I connect the contacts on the connector the brake lights turn on.
  • Bought two brake switches.
  • Confirmed the brake switches work
    • Multimeter connected to the contacts + push the metal panel == connectivity
    • Connected the brake switch to the wiring, pushed the panel -- lights came on
  • Replaced the brake switch (tried both)
After installing the brake switches back I am seeing the same symptoms: the brake lights come on only when the pedal is almost at the floor. For comparison, if I'll be driving at 50mph and press the pedal this hard, the wheel will lock. I.e. that's not a valid behavior of the switch.

Should I try to bend the switch panel to make it more sensitive?
Could I be missing some bushing required for proper work of the switch (some topics on forum say plastic bushing has to be removed)?
Is that something to do with CSRP's adjustable push rod?
Is there some specific way how the switch needs to be mounted to the push rod (I tried with white silicon bushing going under and over the right "shoulder" of the switch, it made no difference)

PS: brakes were replaced a year ago by reputable mechanic experienced in classic American cars, pedal seems to be properly adjusted (0.5 inch travel in top); the issue started only recently.

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Yes, but I only have one white bushing on the push rod.
Need two. One on the inside, one on the outside. Place black bushing in the hole in the pushrod first, then slide, with switch, onto pin, place other white bushing and then clip.
 

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Won't work well with a dual-circuit system (in case of hydraulic failure in the circuit with the light switch you'll have no lights).... if you DO go that route, stick it in the circuit fed by the rear (primary) m/c port. Of course, you can use TWO switches wired in parallel......
 

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Discussion Starter · #7 ·
Need two. One on the inside, one on the outside. Place black bushing in the hole in the pushrod first, then slide, with switch, onto pin, place other white bushing and then clip.
Woodchuck, any chance you know where can I buy the right set of bushings/washers?
 

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Try putting in the extra bushing first (you can get at NPD, CJPP, Summit, etc.), but if that doesn't work, a thin piece of folded-up aluminum foil (or thin aluminum sheet) folded over the brake switch contact plate can help close the gap, in case the brake pushrod is just not contacting it correctly.
 

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Discussion Starter · #10 ·
I got the bushings/washers from NPD and tried to fix the issue today. After checking the picture shared by Woodchuck above (and several videos) I realized than in my case I only had one bushing installed to the right from the switch (photo below).

I removed it, installed a white washer instead and a black bushing on the brake push rod’s hole. I don’t have room to add one more plastic washer, in fact I can’t even get a pin through both holes.

So far, no luck.

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I got the bushings/washers from NPD and tried to fix the issue today. After checking the picture shared by Woodchuck above (and several videos) I realized than in my case I only had one bushing installed to the right from the switch (photo below).

I removed it, installed a white washer instead and a black bushing on the brake push rod’s hole. I don’t have room to add one more plastic washer, in fact I can’t even get a pin through both holes.

So far, no luck.

View attachment 854232
That does NOT look like the right washer (unless the pedal pushrod bushing is white and not black). The shouldered spacer goes inside the pedal pushrod, from the "outside". One white washer on the inside, install the pedal pushrod and switch as a unit, then the other washer on the outside, and the hairpin.

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Discussion Starter · #14 ·
Going R to L -> skinny washer + brake pedal pushrod + bushing + switch + skinny washer + cotter pin. Correct?
That was the goal, but there’s bout brought room to fit all bushings in my case… unless I didn’t fit right some of them
 

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Discussion Starter · #15 ·
That does NOT look like the right washer (unless the pedal pushrod bushing is white and not black). The shouldered spacer goes inside the pedal pushrod, from the "outside". One white washer on the inside, install the pedal pushrod and switch as a unit, then the other washer on the outside, and the hairpin.

View attachment 854239
Yes, this is what I was trying to achieve, but I don’t have enough space to fit the last one white washer. Here are the pictures of what I have now. Note I can’t get the pin through as the switch partially overlaps with the hole the pin is supposed to come out from — even without the last washer :unsure:

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Yes, this is what I was trying to achieve, but I don’t have enough space to fit the last one white washer. Here are the pictures of what I have now. Note I can’t get the pin through as the switch partially overlaps with the hole the pin is supposed to come out from — even without the last washer :unsure:

View attachment 854249 View attachment 854248
It almost looks like there is another washer or something stuck on the pedal pin....
 

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Discussion Starter · #18 ·
It almost looks like there is another washer or something stuck on the pedal pin....
Thanks, that’s exactly what it was!

Turns out there was not only a shouldered bushing but also an old washer on the male connector of the pedal. It was old and dirty, hence the same color as metal.

After taking it off I was able to reassemble the whole construction with new bushings and washers. Still not perfect — required at least 80% of pedal travel to get the stop lights.

Tried adding a thin piece of metal but it wasn’t thin enough — couldn’t get the switch on the male connector.

So, as a last resort I decided to bend the contact panel of the connector a bit more to make less travel required before the flat surface of the push rod actually pushes the connector. Used two wrenches, bent both sides a little bit, put the connector on, hooked up a multimeter to the switch’s contacts — and voila — we’ve got connectivity exactly where I wanted it! Put on all bushings and washers, got the pin back in — and the brake lights now work exactly as they should!

Thank you all for your help! This was an issue caused by a combination of factors and all your advices helped me to find a solution. This community is awesome!

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