Brake Light Switch Replace, To Bleed Or Not To Bleed

Hi All, So, I did a search for non working brake light. All other lights work. So I jumped the two wires going into the Brake switch at the MC and the tail lights went on. It is a brand new dual master cylinder so I am guessing the hydroponic brake switch crapped out. So...
1. Do I need to bleed the system when replacing (boy would love not too)? Opinions vary wildly on this it seems.
2. If so then, can you send me to a good youtube vid on how to do it. I have never done one.
3. Someone mentioned 'Standard' makes a good BLS. Can anyone recommend a well made (post terminal) switch?
Thanks folks.
Cheers,
D

 

I have changed mine out over the years and never had to bleed brakes

 

Ah great idea filling the switch cavity! Thanks for the feedback guys. Is there a good hydrolic brake switch out there? I read on line NAPA wasn't very good nor the summit racing offerings. Kaiser willys is 16 bucks - which I don't care as long as the quality is up to snuff. Thanks again! Puts my mind at ease...

 

If your rear brakes are spongy it can cause the switch to not to close contacts and not work. You may want to bleed brakes anyway as a precaution. Filling the switch will not be easy. You need to insert a straw or similar to allow the air to come out as you fill it or a syringe or similar to fill it. There are also different pressure switches that use more or less to close contacts.

 

All the drums were serviced when I had the dual MC put in. Springs etc. Serviced or replaced. So they should be fine (I hope). Appreciate the additional info!

 

I bought a low-pressure switch from Ron Francis (.com). Thirty bucks, but the brake lights come on without having to 'stand' on the pedal. Only a gentle push..... Worth it, to me anyway

 

You may be able to get away with not bleeding after replacing the switch but as 47v6 said it would probably be a good idea. Why? Because you may get air in the line when you change the switch. There may be air in there already. It gives you a chance to get some of the old fluid out and get some new fluid in (good maintenance). In this particular case it would give you a bit of practice learning how to bleed brakes (it's not hard to do). Good Luck.

 

I put silicone brake fluid in my system when I first built it didn't want any leaks to take the paint off. Well I had some leaks, had to tighten up some connections. What I didn't know is that you cannot go back to regular brake fluid after you put silicone in your system. I went through a brake light switch every year, I went to Ron Francis and bought a silicone brake light switch, problem solved. I never had to bleed my brakes, I learned this from motorcycles with juice brakes, you are so close to the master cylinder that the bubbles will go back into the master cylinder when you let of the brakes, thus no bleeding. It worked for my anyway, more than once, Best of luck what ever you do.

 

Thanks guys! I finally found a roll bar and am in the process of getting that back plated and ready for install. I did pick up a Painless 15 dollar switch.
I did hear that close to the MC does work to your favor. I am going to pre fill switch and try to swap quickly. I may get the jeep serviced in fall due to the upcoming plow season (and with that a brake fluid service). Appreciate the info, huge help!!! I will report back in case anyone else is interested in the results/experience.
Cheers

 

Flushing the brake fluid is one of those service recommendations that everyone should do, but no one actually does.

When I do it (rarely) it gives me a warm fuzzy feeling of being very virtuous

 

Tell me about it! Hadn't changed it in on of my cars for eons and paid the price. Learned the hard way - gotta keep the water out and brake fluid fresh!

 

I am in need of a new switch for my 55 I may go this route, this looks like the switch

SW-32 LOW PRESSURE HYDRAULIC BRAKE SWITCH-Ron Francis Wiring

 

Indeed, that's the one. But as I see the picture, I'm reminded that no way could I use that wiring connector as substitute for my stock bullet connector brake wire ends. I ended up using rubber protected alligator clips on the switch terminals and female insulated crimp-on to accommodate bullet end of brake wire. (the crimp is for joining to wire with alligator clip)

 

Note that flushing the brake fluid is pretty easy with speed bleeders. https://www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias=aps&field-keywords=speed+bleeders

You may need to remove the bleeder valve to determine your bleeder size. At that point, you are committed to at least bleeding, if not flushing. I would caution that you cannot predict what the bleeder size is if the car does not have the factory original wheel cylinders.

 

I love my speed bleeders. Have them at all 4 corners.