Brake Light Switch

[TodFitch]

Thanks for your input Tod. Question: When the switch is removed does brake fluid pour out...like...Will it empty the master cylinder quickly? Or do you have time to reinstall the new one before a huge mess is made/master cylinder is emptied/making it necessary to rebleed the brakes...Did you put teflon tape or pipe dope on the threads?

Thanks, Bob

On my car the master cylinder is above the other brake components and the brake light switch mounts to a fitting on the outlet of the master. When I removed the old switch a drop or two of fluid overflowed out of the opening. I did not use tape or dope on the threads. A steel pipe thread screwed tightly into a brass fitting should not require the use of sealants...

[41PlySD]

Could you have gotten some dirt in the very small hole on the switch where it detects pressure?

The switches are readily available at any decent auto supply and can be swapped out without re-bleeding the system. At least when I changed mine out this summer I did not need to re-bleed.

Thanks for your input Tod. Question: When the switch is removed does brake fluid pour out...like...Will it empty the master cylinder quickly? Or do you have time to reinstall the new one before a huge mess is made/master cylinder is emptied/making it necessary to rebleed the brakes...Did you put teflon tape or pipe dope on the threads?

Thanks, Bob

[TodFitch]

Could you have gotten some dirt in the very small hole on the switch where it detects pressure?

The switches are readily available at any decent auto supply and can be swapped out without re-bleeding the system. At least when I changed mine out this summer I did not need to re-bleed.

[41PlySD]

Brake Light Switch is not working on my 57 Plymouth...I made sure the wiring and bulbs are ok by shorting the wires on this switch; the rear brake lights do come on. I recently rebuilt the front brakes replacing the wheel cylinders/hoses and brake shoes. I bled the front brakes...pedal is good...car stops straight but it does seem very suspicious that the brake lights and switch was working fine until I did this work. Is it possible I need to bleed the brake light switch too? Could there be air bubbles trapped behind it reducing brake pedal pressure? Anyone ever have this happen to them?

Thanks, Bob