Brake lights are slow to come on

Hi everyone,
I'm having some trouble with my brake lights. They are very delayed when stopping. I'm practically half way stopped before they come on, and if I'm in stop and go traffic they hardly ever come on. I'm really worried about being rear-ended.

I am running this dual circuit master cylinder from CB performance with cb performance discs up front and stock drums in the rear.

I thought I may just have bad brake light switches, so I ordered two OEM switches from OEveedub. They were out of stock and sent me two generic ones. I called and was told they shipped me Olimpic brand switches, but they don't look like the old Olimpic switches I removed, so I'm really not sure what brand they are. They have no markings. I decided to just try these switches and the results are the same. Delayed brake lights. I re-bled the system after putting the new switches in. Dual circuit so I went LF, RF, LR, RR. Pedal is hard as a rock and brakes are excellent.

What else could be the problem??? A total of 4 switches all produce the same result, so I'm guessing it must be something else. Could a faulty master cylinder cause this? I though there may be air trapped behind the switch, so I tried bleeding the switches by having my wife pump/hold the brakes while I cracked the switch open a tad to let fluid out. That didn't help.

Unfortunately, I have no idea when this issue actually started, just something I noticed a while back. I'm not sure if it was happening when I was running a single circuit MC with front drums cause I didn't have that set-up very long.

Thanks for reading. Any ideas/tips will be greatly appreciated!

Hey Eric....just curious but is it possible to get a couple lengths of wire and an extra light of some sort to wire up just to the switch just to see if it is slow to come on when you hit the brake pedal.And don't the wiring for the brake lights run through the fuse block ?

Well, I'm running snowflake taillights on a car that shouldn't have them, so I have to run my brake lights and turn signals through a trailer converter. I thought that may be the problem, but I'm also running a third brake light (led) and that one does get power straight from the brake light switches, and it's slow to come on as well.

Do you own a multimeter? If not borrow one and crawl under the car and check the switches.

Just checked them with the multimeter. Had the wife slowly pushing the brake pedal and watching for the reflection of the brake lights on the garage door. I watched the multimeter and waited for her to tell me the lights had come on. Multimeter read 0 until right when she said the lights were on, then I got 12.54 volts.

Have you checked your grounds? I had a prob like that a long time ago on my73 beetle and that fixed it. I guess the rust delayed the completion of the circuit. Good luck.

Yep, grounds are all good. Even ran dedicated wires from the bulb housings to the fender bolts.

Check the continuity at the switches. Pull the wires off and use the ohm setting and have someone push the brake pedal. If it does not go to zero immediatly its the swith or m/c. If it locks in as a closed circut off the bat then its elsewhere in the system. My guess is the switches themselves, hard to get that small air pocket out inside of them. You can also short out the switch and see if the come on immediatly, jump the power feed to the output on the switch with the wires attached or pull the wires off and connect them, might be quicker than using a meter.

A few ideas...

- Adjust the rear shoes all the way out and see if that helps the lights engage quicker. If not, start by elimintating each other variable.

- Disconnect the third light and test again.

- It seems that, if it were the converter, the signals would work slow as well. See if the signals in the rear are in sinc with the fronts when you engage the flasher. I have a similar unit on my buggy and read in the buggy forums certain types have a high failure rate. It could be the converter (since it's and electical doodad) is slow to respond in the cold. The digital readout on my radio in my bus is slow to respond when it's below freezing outside. Leave your cell outside for a few hours tonight and you'll see what I mean when you try to use it.

- All that being said, brake switches have a high failure rate (I'm guessing in the 30-40% range) you could easily have one or even two bad switches. It's happened to me before. Take the switches off the MC and flip them around front to rear and rear to front. Then test again.

- Could also be the plunger from the pedal to MC needs to be adjusted as well.

I would be willing to bet five bucks it's the damn switches. I have one extra "nice" switch. Give me a call if you want to try it.

Thanks Glenn, unfortunately I don't think it's related to the cold, they were doing this in the middle of august too! I'll try bypassing the converter and third brake lights to see if either of those help. I've got the pushrod adjusted per the Bentley, but I can fiddle with that and the shoes a little and see if I get better results. Got a paper due tomorrow though, so I'm not sure how much time I'll have to mess with it today.

Just mash the brakes earlier. Lol

camch wrote:Just mash the brakes earlier. Lol

That's what I've been doing already!
Jerome, missed your post earlier, but I have already tested by jumping the terminals on the switch, and they light up instantly when doing that. Probably be a little bit until I get around to messing with them again. Gonna try all this, and someone on the samba mentioned filling the hole in the switches with brake fluid before installing them to help keep that pocket free of air. gonna try that as well.

I've noticed this once when following you. It is slow. I know you don't want to here this but I would say a defective M/C. If the lights come on the moment you touch the wires together then it can't be electrical related. It takes pressure to push on the switch and if the pressure is low then that's why it takes a few seconds for the switch to make. Is it a dual circuit M/C? If it is a dual circuit you could use the other switch? Or have ya tried that?

It all goes back to pressure. The driver behind ya is now under pressure to stop b/c he had less time to react! LOL

Yeah, it's dual circuit, and I have both switches wired in parallel so they are both wired up. Gonna try all the above suggestions soon, and if all else fails, I'll get a contact switch and fab up something behind the pedal itself. My dad has something like that on his 57 panel truck and it works great. I'd rather not do this, but it'll get me by while I keep trying to find the real problem.

I've got another dual circuit master from WW, but it is for stock drums all the way around. The one I am running is from CB and they recommended it for disc brakes due to the larger bore.

I wonder how necessary that larger bore really is???

larger bore is necessary, stick with it. like Bob said,it is about pressure...but if the MC did not produce proper pressure you would feel it in the brakes. check the hole on the switches, i have seen these get clogged or be improperly drilled from the manufacturer. i had a set before that i "cleaned" out with a tiny drill bit by hand and they worked proper afterwards. DO NOT use a power drill and DO NOT drill too deep, you are just cleaning it out! i ran a GM style contact switch on my other Bug and it worked great! good luck

I'm definitely going to clean them out, but I just have a feeling it is something other than the switches. I know aftermarket parts are crap, but between the two I removed, and the two I replaced them with, that is 4 that all acted the same. Surely I'm not that unlucky to get 4 bad ones.

Welcome to my World!

Pulled both switches again today and cleaned them out, filled them with fluid to get all air out, re-installed them and re-bled the system twice. Same results. Disconnected all wires and then tested each switch with a test light. Did this to rule out any problems with the trailer converter or grounds. Test light gave the same results for each switch. Delayed like a mofo!!!

I want to get my car back on the road, so until OEveedub gets the good german switches back in, I'm going to fab a small mount at the base of the pedal and put a momentary switch in. Here's where I need some guidance from the electrical gurus on this site. All the small momentary pushbuttons I could find were AC, not DC. I got one that is rated 5amps @ 125VAC. Will this work ok on a 12VDC system??? I also bought a relay in case I needed to put the lowest possible amperage draw on the momentary switch. I tested it and it worked great, but will it hold up over time on a 12VDC system? I know very little about voltage and the relationship to amps, so I'm hoping this will be do-able. if not, I'm only out a few bucks.

On a switch not running the high voltage you should be alright. A switch is nothing but a dry contact. Getting the push button type to work with your pedal is going to be tricky. I had to do something similar on my 62 and used a cherry switch. Basically a pushbutton but with a metal arm that depresses the button. With this set-up and a fabbed up longer arm could have the switch go instant and the flex of the arm would allow for extra brake pedal travel. You really do not want the switch to be able to hamper any travel, might cause a problem down the road.

Another thought on your switches, you do not have to use them both. You can wire just to one and have the same effect. If need be I might have some older switches if needed to test but its sounding like maybe the switches your getting are the wrong pressure or the mc is clogged up somehow preventing the pressure from hitting immediatly.

If you want can pm you my # and might make more sense over the phone vs playing tag on here.

meinvw wrote: Basically a pushbutton but with a metal arm that depresses the button. With this set-up and a fabbed up longer arm could have the switch go instant and the flex of the arm would allow for extra brake pedal travel. You really do not want the switch to be able to hamper any travel, might cause a problem down the road.

yep, that's the type I got. The arm has a small roller at the end of it. I'm mounting it right at the base (pivot point) of the pedal, so the travel of the pedal there is very minimal. I've already bent the arm a little to get a few extra mm of travel out of the switch. Looks like I'll have plenty of room even after the brakes wear some and the pedal goes down farther.

meinvw wrote:
Another thought on your switches, you do not have to use them both. You can wire just to one and have the same effect. If need be I might have some older switches if needed to test but its sounding like maybe the switches your getting are the wrong pressure or the mc is clogged up somehow preventing the pressure from hitting immediatly.
If you want can pm you my # and might make more sense over the phone vs playing tag on here.

Yeah, I know both aren't needed, but as crappy as these switches are, I'd just prefer have them both hooked up and working. I found some painlesswiring switches that are specifically for "low pressure" applications. I thought about ordering them, but wasn't sure if the thread size/pitch would be the same. I'm hoping OEVeeDub will have the others back in stock soon! But I'm the type of person, who once I get this contact switch in, I'll probably be too damn lazy to change the pressure switches out again.

When your using both switches if one goes out then nothing works. better off using one and if it goes bad just switch them to the other. basically adding another element into the mix that can go bad.
on the cherries use the no and c, nc is not needed. Polarity does not matter you can put a hot to no (normally open) or the common (c). Good luck with it!

meinvw wrote: When your using both switches if one goes out then nothing works.

Whatchoo talkin bout Jerome? I've got them wired in parallel, so both switches have power going into them. And the "outputs" of both switches are pigtailed together and then running to the brake lights. This way if one goes out (failing in the off position), the other still has power in and an output to the lights. Of course if one fails in the "on" position, then I'm screwed with brake lights always on. Drove halfway home from YU Buggin 2.0 in that position!

meinvw wrote:
on the cherries use the no and c, nc is not needed. Polarity does not matter you can put a hot to no (normally open) or the common (c). Good luck with it!

Took me a while to figure out was going on with the switch when I was messing with it earlier. Really cool that it can be operated both ways! I'm gonna rig everything up Friday. I'll post back on how it goes!

fluxcap wrote:

meinvw wrote: When your using both switches if one goes out then nothing works.

Whatchoo talkin bout Jerome? I've got them wired in parallel, so both switches have power going into them. And the "outputs" of both switches are pigtailed together and then running to the brake lights. This way if one goes out (failing in the off position), the other still has power in and an output to the lights. Of course if one fails in the "on" position, then I'm screwed with brake lights always on. Drove halfway home from YU Buggin 2.0 in that position!

Maybe that was worded wrong, I know exactly how your wired, ok, maybe the car at least! But having them set up this way is just adding a back up in case one fails. But its also adding another element to troubleshoot. heres a thought, do you have a spare wheel cylinder? Put a short line into the wc and attach it to the switch port, pump up the brakes and bleed the wc from one of the switch outputs. maybe even do both, but see what kind of pressure you have using this set up. If you do try this put a c-clamp on the wc so it does not blow apart, but leave some room so you can see if its working. probably need to go back and re-read the whole post, but was this an issue before? Just appeared? was the mc was replaced? I think you do not have the pressure from the mc to the switches. Either trash, non existining qc on the mc, or something is keeping the pressure from hitting the switches. Maybe try pulling the mc and pull out the plunger/internals and try drilling out the switch ports. If you do try this be sure and re-hone the main chamber on the mc.

ok, i'm a little confused, do you mean, that after you mash the pedal the brakes take a a few seconds to come on, or do you mean, you have to push the pedal hard for them to come on?

Eric , was thinking also the pressure may be messing with you between the front disc and the rear drum. I would bet the fronts are grabbing before the pressure is high enough to make the switch. Just a thought pull the wheels on one side and see what you have when on the grab for front and back. The switch wont make until pressure fills to make the MC switch as you well know.
Maybe you can do some adjustment on either- then hopefully you wont have to use the cherry switch.