silicone brake fluid proof brake light switch

[Ian NZ]

Originally Posted by JSeery

Bad cups? Have you considered a residual valve to maintain some pressure on the wheel cylinders?

Do you think you really need to run a 2-lb residual valve in the Ford V8 hydraulic brake systems, i thought that was already incorporated in the V8 master cylinder.

[JSeery]

Originally Posted by Ian NZ

Do you think you really need to run a 2-lb residual valve in the Ford V8 hydraulic brake systems, i thought that was already incorporated in the V8 master cylinder.

Depends on the master cylinder, some have them and some do not. Not having them can be a source of wheel cylinder leakage.

[FlatheadTed]

Thanks for the tip ,The duel M cylinder is a modern one so I would think maybe there is a valve in the out let only , ? disk and drum M/C

Originally Posted by JSeery

Bad cups? Have you considered a residual valve to maintain some pressure on the wheel cylinders?

[JSeery]

Maybe, maybe not, depends on how the system was set up. As an example might have had a combination valve that served that function.

[Automotive Stud]

Originally Posted by V8COOPMAN

Suggestion below! DD

Ron Francis sells a silicone compatible switch that has been mentioned here several times.

http://www.ronfrancis.com/prodinfo.asp?number=SW%2D32



Item Number: SW-32Unit Price: $28.95In Stock

I know this is an old thread but I'm running dot 5 and I'm on my second one of these switches in two years. Does anyone really offer a true dot 5 compatible switch?

[JSeery]

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I thought the Harley switches were, but not positive.

Update: Genuine Harley Davidson, part # 72023-51D

OK, second update! This was already covered in detail earlier in the thread!!!!

[38bill]

I was running the Harley switch and it failed too. I ended up switching back to DOT3 when I did a total rebuild of the brake system.

[nelsb01]

So, does anyone have an answer? I was over reading the Harley boys forum and they are not buying HD switches because they are not made by HD and fail. They suggested Accel 181101.
Anyone using that one? I am gettting tired of the 9 month and replace $9.99 ones that I now buy 10 at a time.

[tiger.1000]

I agree with BINX. Don't use silicone fluid. Stay with DOT 3 and perhaps every two years or so bleed the system and renew the fluid. £5 will buy you a brake fluid tester which will determine if there's any water in the system and it's water that's the killer.

[richard crow]

i use the chevy lever switch the reason is they can be adjusted to be more senative the hydl switch requires pressure. the lever switch puts the lights on sooner giving the car behined you more time to know your stopping .plus i use dot five if your car sits it,s the best way to go

[deuce lover]

I'm with Richard.To me the hydraulic ones are a waste of time.The lever switch is the only way to go.Its foolproof. Just touch the pedal slightly and the brake lights come on.Used it on last 5 cars I built.Speedway has them pretty cheap.


Here it is $6.99 at Speedway



https://www.speedwaymotors.com/Speed...itch,1972.html

[TJ]

I've used the lever switches for years. Never had one fail so far. It's a simple solution when using dot 5 fluid. Depending on where you buy the switch they cost between $10-15 and it's a one time purchase.

[Tony, NY]

Yeah. Give up on the hydraulic switch and go to one off of the pedal, as said.
https://www.amazon.com/Allstar-Perfo.../dp/B003C01FFY

[Ronnieroadster]

Years ago when i had the same failure with silicone fluid and the original style brake light switch i spent time trying to figure out why they fail. I found the seal in the brake light switch was the problem its not compatible with silicone. Once the seal fails the two contacts inside the switch are now flooded with the silicone fluid. The fluid now is causing a high resistance to make the contacts work correctly if i pressed really hard on the pedal the brake lights would work. Any heavy duty brake light switch would still have the same problem there called heavy duty to handle more load not a change in brake fluid type. My solution is exactly as others have written a mechanical brake light switch problem solved.
Ronnieroadster

[d.conrad]

HD switch is smaller and cheaper than Ron's ( about half the price).. Works great and I'm told HD uses silicone brake fluid.

[alanwoodieman]

I have a HD switch on my wagon for almost 30 years! bought a ron francis switch for my 41 truck and it lasted about 10 years. silicon molecules are so small they sneak past the disc in the switch effectively neutralizing the switch

[Yoyodyne]

I don't think it's the silicone fluid making them fail. I started having those switches fail 40+ years ago before there was silicone fluid. old ones lasted for years, newer ones failed in a year or so with DOT3. American made, etc.

[vanhammer]

Originally Posted by alanwoodieman

I have had two of Ron Francis's swithes fail, so far none of the HD switches have failed? when they failed the silicon got thru the seperation and hydro locked making the switch not work-how do I know this, I drilled on of the switches and fluid ran out, after letting the fluid out the switch worked

I know this post is old, but I got one of the Ron Francis switches in 2016. Did not install it for a year or two and I have not even put 100 miles on the car. I dont have any brake lights now unless I press very hard on the pedal. I am running less than 3 amps through the switch. Warranty is out of course, but they would not even knock off a small percentage to get another one. I think I will go with the HD one.

[Automotive Stud]

Yeah I've switched to the lever switches on all of my cars after having two Ron Francis switches fail. Never tried the Harley but I was tired of messing with it. I only had one lever style switch eventually wear out and it was 20 years old.