I run DOT 5 brake fluid in my roadster, and the other day a guy told me my brake lights did not work. I noticed Mac's Auto Parts sells a brake light switch (for the back of the MC) that says it is DOT-5 compatible. I have never heard of this, and run just a plain jane 2 prong Ford switch. Did the brake fluid ruin the switch I have?? If they are special, does anyone know of a part number for one that will work from a local parts store?
Get one from the Harley shop. They have used DOT 5 Silicone for years and use the same style screw in switch. Get a genuine Harley one as most of the aftermarket ones aren't worth a crap
Thanks guys, I cannot find any proof that the switch needs to be special for DOT-5, maybe I just have a cheapy that went out. I have yet to test the system, just thinking out loud
I think there are some in line switches that are killed by Dot 5. I had one on my 23 and it stopped working after a short while, same thing happened to my Son on his T bucket. We are both running Dot 5. Not sure what effect is has, but evidently something in it harms them. Don
ive gone thru 2 ''carquest'' brand crap switches---im now using a ''standard'' brand---my bud said my lights are not working again---i will throw in the painless one and go from there--which is the ''better brand'' aka the good stuff?
I buy my switches from Speedway. I havent had one go out, interesting though about DOT-5.... Not to hijack, but why are you guys runnin DOT5?
Just a couple of thoughts. Is it dot 5 or 5.1? Dot 5.1 is more like dot 4 with a higher boiling point and is compatable with 3 and 4. Dot 5 is a full synthetic brake fluid and some of the early blends cause swelling and or leaks in systems. Make sure that you bleed very carefully so there is no air or moisture. The silicone base won't absorb moisture but will contain it in one area. So that area is susceptible to rust or corrosion. It also has a different braking feel, more spongy and soft compared to rock hard as with 3 and 4. It is a thinner more "vitreous" and so it can drain away from your switch. As for the switch try Ron Francis, they have a low pressure brake switch for use with 5 and that might take care of your problem. Or I would install a mechanical one on the pedal. Looks like my slow typing and work delays led to a very slow response time. You have already been informed. Good luck
Thanks, its what I was thinkin, and couldn't figure out why to run dot5 unless you have stainless lines.....
the main reason that I know of that people like DOT 5 is it does not eat paint or powder coat when you spill some or have a leak.
If it messes up the stoplight switches,....add that to the list of reasons to not use DOT 5. If one has a need to run DOT 5, then why not a mechanical switch? 4TTRUK
This Delco is available in left or right. About $7 at swap meets and $20 at auto parts stores The arm can be bent or drilled and tapped so it can fit anything easily
I just installed a Harley switch in my '32 with Dot 5. It works but the lights stay on a few seconds longer after I release the pedal. I have not bled the system, I'm guessing that all the air in the lines is causing it to do that. Anyone else come across that problem?
Wouldn't call that much of a problem. Its never happened to me but staying on a bit longer is much better than a delay in coming on.
DOT 3, 4 and 5.1 are virtually identical. God only knows why they decided 5.0 would be different, and why 5.1 is not like 5.0. I put 5.1 in my Harley, as the guy in the store told me it was virtually identical to 5.0 Dumb-ass me for not checking these things myself, and actually trusting a guy in an auto supply.
My '32 had a hydraulic switch but you had to stand on the pedal before the lights came on. I switched to a Ron Francis low pressure switch and it cured my problem. People said the switch wouldn't last so I bought two. 13 years later, I finally gave my extra switch away.
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