Brake light failure - switch replacement

[curlesw]

My brake lights stopped working and I see the switches on the MC are generally the problem.

Question: does fluid come out when you take the old pressure switch out?

I assume no but just want to verify.

thanks.

Wayne
83 SC

[Por_sha911]

You can keep the fluid loss to a minimum if you put something on the brake pedal to keep it depressed (like a stick at the correct length). There will still be a few drops but it will be minimal. Plan on bleeding the system afterward to be safe. Frankly if it hasn't been done, just do an entire flush of the system. Its a small price to pay for dependable brakes. Do a search, there is a ton of info on this board about it. Don't forget that brake fluid is very nasty stuff so keep your hands clean when touching the paint or interior.

[curlesw]

Thanks Joe, will do.

Wayne

[acapella8]

If you're quick, you will not lose much, I had PB blaster working on mine and had the replacement switches ready, didn't lose more than a few drops. Good luck and post results.

[Por_sha911]

p.s. Don't be tempted to replace only one switch and see if its fixed. Replace both switches at the same time.

[DRACO A5OG]

When you stated Brake Lights Failed, do you mean they were slow or not working at all?

When was it last replaced?

[rnln]

Yes it will come out a little bit. If you swap them straight, I assume you will allow some air into the system. Draco was helpping me by slowly pusshing the brake petal to push as much air out while I am "plugging" in the new switch.

He also helpped me to install the new BLASAS (the new device to protect my new switches. We took some pictures and short movies but I don't have time to load them up yet. The thread below my help you some ideas.

http://forums.pelicanparts.com/showthread.php?t=390422&highlight=brake+light+switch

[curlesw]

Originally Posted by DRACO A5OG

When you stated Brake Lights Failed, do you mean they were slow or not working at all?

When was it last replaced?

DRACO, I meant that they are no longer working. Every electrical component on the car works except the brake lights. I checked the bulbs and they are good.

I did a quick search and found this to be a common problem...hopefully this will fix my issue...I can't think of anything else.

Note: I did remove/replace my engine last week...but can't think why that would cause a problem.

Wayne
83 SC

[rdrr]

As far as I know, the brake light switches don't cause total failure. The brake lights simply come on a little late, i.e. with more pressure on the brake pedal. It may be a good idea for you to change them anyway, but by the sound of it, it might not fix your problem.

And +1 on putting some pressure on your brake pedal when changing the switches. I've done it twice - once with pressure on the pedal and once without. With pressure, there is virtually no loss of fluid.

[curlesw]

Thanks Eckhard.

I'm going to replace them and see if this works...if it doesn't, I'll be stumped.

Wayne C.

[rdrr]

You might as well. Fingers crossed that it does fix your problem!

[rnln]

If you know how to measure ohms using an ohm meter, you can measure across the prongs on the switch while someone pressing on the brake pedal to know if the switch is bad or not.

[curlesw]

Originally Posted by rnln

If you know how to measure ohms using an ohm meter, you can measure across the prongs on the switch while someone pressing on the brake pedal to know if the switch is bad or not.

I hear ya...good idea, should have thought of that myself since I have a EE degree...

Wayne

[VaSteve]

Please tell me how to "be quick". The switches are in a tough place and I have to use all sorts of tricks to get my deep 24mm socket on there and get them removed. They weren't exactly easy to get out. Perhaps I should have taken off more of the HVAC piping...or all of it.

Just flush when you're done. You'll be fine.

[rnln]

I only had a year or so before I changed my major. Look like I was dancing in front of a master
Good luck.

Originally Posted by curlesw

I hear ya...good idea, should have thought of that myself since I have a EE degree...

Wayne

[curlesw]

Just a quick update. I changed both switches and now the brake lights works!

The back switch is a pit of pain to get to, a small 24mm socket works better than the deep socket...I had to move a few items to get to the switch. No big deal, just to a bit extra time.

Thanks for everyone's help.

Wayne C.
83 SC

[rnln]

Then sounds like it is the famous switch problem then, but in this case, Wayne left it long enough that it quit working after a long time (should be) of be slow.

[Al S]

I just replaced mine....

It's very simple, all you have to do is prefill the new switch cavity with an eye dropper. Take your time, and make sure all the bubbles are out. Use a wire, tap the switch, etc..

Remove the old switch, then quickly install the new one. Don't screw the new one in just yet, first tip the body down slightly, so that you "burp" the cavity in the MC. Fluid is cheap, so burp it real good. Screw the new switch in, and you're good to go!

[Texel]

Just changed both switches on a '88 coupe, the front one was easy to find locally, but the rear one was a real drama, it is 2 prong and has reasonably close set prongs, and the female part can't really accept any other type without modification.

I found this one from early VWs (apparently) and it was perfect replacement, so that might be handy to know

[Emission]

Thanks to this thread... I diagnosed, and fixed, my brake light failure!

Ordered two "ATE Brake Light Switch on Master Cylinder (2 Pole)" from our host.

Removed (or pulled out of the way) several HVAC vent pipes. Used a deep socket for the close one, a wrench for the furthest one. Plenty of cursing... but I took my time and everything went well (they really need some muscle to remove)!

Of course, I bled the brakes afterwards... just for peace of mind.

Thanks everyone!

- Mike