Hemi Joel Posted May 13, 2022 Share Posted May 13, 2022 Hi, On my 1929 Cord L29, the brake light doesn't come on unless I'm really stomping on the brakes. I have a similar situation in my 49 Plymouth, but not quite as bad. Does anybody know of a very sensitive hydraulic brake light switch, something that would activate with just barely a touch of the brakes? Preferably something that could be found locally if a guy had the part number or the application. I have considered installing a mechanical switch on the pedal somehow, but it seems it would be much cleaner and simpler to replace the hydraulic switch with a more sensitive one. Thanks very much, Joel Link to comment Share on other sites More sharing options...
Matt Harwood Posted May 13, 2022 Share Posted May 13, 2022 They seem to vary. I've been through five or six different switches for the same reason you mention--just too much pressure required. The one I have now eventually limbers up and works well but the first few stops I really have to stomp the pedal to get it to wake up and start working. I'd bet they're all made by the same company. I have one more that's from a Harley-Davidson motorcycle sitting on my desk right now that I'm going to try--I figured the hand brake on a bike would have a lot less pressure than the foot brake on a car, right? It's part number 32-0425 from V-Twin Manufacturing, if that's helpful, although, like I said, I haven't tried it yet. I bought it on eBay for like $25. 3 Link to comment Share on other sites More sharing options...
Scott Bonesteel Posted May 13, 2022 Share Posted May 13, 2022 Ron Francis Wiring has what they call a low pressure hydraulic brake light switch, claimed to activate as low as 20# versus the circa 60# of a normal switch. Haven't tried one but their products generally seem to be quite high quality and as represented. I have had one of their full wiring systems in one of my cars for 40+ years without a single problem. They have an on-line catalog, see attached link. Good luck. SMB https://www.ronfrancis.com/product/709 1 Link to comment Share on other sites More sharing options...
29 Chandler Posted May 13, 2022 Share Posted May 13, 2022 2 hours ago, Scott Bonesteel said: Ron Francis Wiring has what they call a low pressure hydraulic brake light switch, claimed to activate as low as 20# versus the circa 60# of a normal switch. Haven't tried one but their products generally seem to be quite high quality and as represented. I have had one of their full wiring systems in one of my cars for 40+ years without a single problem. They have an on-line catalog, see attached link. Good luck. SMB https://www.ronfrancis.com/product/709 Been using one on my MGB for several years now. They work great! 1 Link to comment Share on other sites More sharing options...
Buick35 Posted May 13, 2022 Share Posted May 13, 2022 My 35 Buick was the same way.I don't know how you're is activated but on mine I shortened the rod or linkage that activated the arm on the brake switch.There's also a way to adjust the switch placement on mine by shifting it to the rear.Mine works as it should now. 1 Link to comment Share on other sites More sharing options...
Alex D. Posted May 13, 2022 Share Posted May 13, 2022 Harley Davison switch has worked well for me after so many people were telling me that I had no brake lights. 1 Link to comment Share on other sites More sharing options...
Rusty_OToole Posted May 13, 2022 Share Posted May 13, 2022 These hydraulic switches seem to be failure prone. Yours may be faulty, in which case, a new one will fix it. 1 Link to comment Share on other sites More sharing options...
avgwarhawk Posted May 14, 2022 Share Posted May 14, 2022 As others stated, Harley Davidson switches work well. I have heard their switches do not require much pressure to operate. 1 Link to comment Share on other sites More sharing options...
60FlatTop Posted May 14, 2022 Share Posted May 14, 2022 21 hours ago, Scott Bonesteel said: Ron Francis Wiring has what they call a low pressure hydraulic brake light switch, claimed to activate as low as 20# versus the circa 60# of a normal switch. If a company took the time to write that in their description I sure wouldn't hesitate to buy theirs. Here is a link: https://www.ronfrancis.com/product/709 I have two cars with that switch and will keep them if I need to replace one. When I can I try to pull a vacuum from the bleeders on my systems when I do brake work. It may or may not make a difference but it brings a little more ceremony to my work and I like that. 1 Link to comment Share on other sites More sharing options...
Matt Harwood Posted May 14, 2022 Share Posted May 14, 2022 On 5/13/2022 at 1:27 PM, Hemi Joel said: Hi, On my 1929 Cord L29, the brake light doesn't come on unless I'm really stomping on the brakes. I have a similar situation in my 49 Plymouth, but not quite as bad. Does anybody know of a very sensitive hydraulic brake light switch, something that would activate with just barely a touch of the brakes? Preferably something that could be found locally if a guy had the part number or the application. I have considered installing a mechanical switch on the pedal somehow, but it seems it would be much cleaner and simpler to replace the hydraulic switch with a more sensitive one. Thanks very much, Joel Can confirm that the Harley switch works with very little pressure. I don't know how durable it is, but just a light touch on the brake pedal turns on the lights. Nice! 1 Link to comment Share on other sites More sharing options...
kgreen Posted May 15, 2022 Share Posted May 15, 2022 Is it possible that that there is an air bubble trapped at the switch? The switch is located on top of the manifold that directs fluid to the front two lines and one rear line, and as a high point, I wonder if a bubble could be trapped at the base of the switch. A bubble of air at that location could be a reason for higher peddle pressure to compress the air before switch activation. During the bleed process I would suppose that high pedal pressure or fast pedal movement may move the bubble out while slow and steady peddle movement would allow the bubble to stay in place. 2 Link to comment Share on other sites More sharing options...
Hemi Joel Posted May 15, 2022 Author Share Posted May 15, 2022 Thanks for all the help. I think I'll give that one from Ron Francis a try. Link to comment Share on other sites More sharing options...
Shootey Posted May 26, 2022 Share Posted May 26, 2022 Is it necessary to do a bleed when switching the switch? Link to comment Share on other sites More sharing options...
Joseph P. Indusi Posted May 27, 2022 Share Posted May 27, 2022 Shootey: I have to change the hydraulic brake light switch in my 53 Buick often because I use DOT5 silicone brake fluid. i have never had to bleed the brake system when I install a new one. Joe BCA 33493 Link to comment Share on other sites More sharing options...
Hemi Joel Posted May 27, 2022 Author Share Posted May 27, 2022 So dot 5 causes frequent replacements of your switch? My Ron Francis switch showed up. I haven't installed it yet, but it does say in the instructions that it is compatible with dot 5. Link to comment Share on other sites More sharing options...
WPVT Posted May 31, 2022 Share Posted May 31, 2022 I had a switch fail prematurely a while back, so I cut it open to take a look. Not much to it, just a spring and some contacts. Pressure sensitivity could probably be adjusted by using a weaker spring. The trick would be opening the housing and then resealing it. Another better option comes to mind....Sourcing an hydraulic pressure switch from another industry, i.e.,one where there is less incentive for producing a poorly made product. Link to comment Share on other sites More sharing options...
dodge28 Posted June 5, 2022 Share Posted June 5, 2022 The only substitute is snake oil. Mechanical at the pedal is the way to go. It is safety you are looking for. Link to comment Share on other sites More sharing options...
Shootey Posted June 5, 2022 Share Posted June 5, 2022 Regarding bleeding the 1948-1949 Buick Shop manual on page 10-85 states “When replacing stop light switch have new switch ready to install as soon as the old switch is removed from distributor fitting. Before installing new switch make sure that port in distributor fitting is filled with brake fluid. Have a helper gently depress brake pedal to fill the fitting from master cylinder, if necessary, then immediately install new switch.” 1 Link to comment Share on other sites More sharing options...
EmTee Posted June 8, 2022 Share Posted June 8, 2022 On 6/5/2022 at 4:10 PM, Shootey said: Have a helper gently depress brake pedal to fill the fitting from master cylinder, if necessary, then immediately install new switch.” I would think the procedure would be to "Loosely install the new switch and then have a helper gently depress brake pedal to fill the fitting and switch cavity from master cylinder while tightening the switch.” Some brake fluid should be allowed to escape in order to be sure the air has been displaced. 3 1 Link to comment Share on other sites More sharing options...
Glen Andrews Posted June 9, 2022 Share Posted June 9, 2022 Okay, so 25 years ago I put Silicone Dot 5 brake fluid in my '38 Chevy pickup, I installed a new switch and needed to really press on the brake pedal in order to get the light to come on, so several years ago I installed a mechanical switch which was adjusted to come on with just a little pedal movement, but sometime the pedal would not retract all the way and the light would stay on. About 2 weeks ago after reading the posts in this thread I ordered SW-32 brake light switch from Ron Francis Wiring. I just finished installing it this afternoon and it works with just a little pressure; so thanks for suggestion. I got the new one in maybe a thread or two and waited for some brake fluid to ooze out from the threads, tightened it up, and cleaned up the excess fluid, and the brake pedal is fine, didn't have to bleed out any air. 1 Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now