'60 Stop Light Problem

[YellowRose]

Mike ~ mpwhd, new to the Forum, has a problem with his stop lights on his '60 Squarebird. Here is what he said.

"I have a 1960 Tbird hardtop and after driving then parking it, about 1/2 hour later the stop lights come on and stay on untill I pull up on the brake pedal !! I have replaced the stop light switch but still have this problem. Can anyone here help ? Thanks in advance !! Mike"

[simplyconnected]

Not much information to go on. Is this manual or power brakes? How long ago were the brakes bled? Were the master cylinder or booster changed recently?

If power brakes, the setup procedures are covered in your Shop Manual on pages 10-12 and 10-15. - Dave

[Nicolas]

Could it be the master cylinder piston not coming back to its original position due to the pedal not coming all the way and after a while, the return springs from the drums applying back pressure to the sensor ?

[simplyconnected]

Nicolas, your thinking is on the right track.
When the M/C piston returns, it opens the ports to all the wheel cylinders. That allows fluid to go back into the reservoir.

If the piston does not return, that port is closed and no more brake fluid can return. Is that such a big problem? There's more...

DOT-3 brake fluid is glycol based like antifreeze. It sucks up water faster than Scotch, which makes it a 'rust inhibitor' until saturation sets in (usually after a few years). Now that the brake fluid has water, the boiling point lowers and the freezing point raises. Water also promotes rust from the INSIDE, causing that redish-brown color. New brake fluid is always water-clear.

Now we have brake shoes that are lightly scraping because fluid cannot return. The friction causes excessive heat which expands the brake fluid even more, causing a lot more heat which causes more brake friction. If the car continues, too much heat will ruin the springs and the shoes will glaze, fail and stink badly. It's a snowball effect.

Notice that much of this depends on the condition of the brake fluid. Your brake system only holds about a cup. Doesn't it make sense to change it every few years?

Folks get all worked up about brake fluid 'eating the paint off their car'. DOT-3 dissolves in plain water. If it gets on anything, rinse it off. There is nothing harmful to the environment in DOT-3 but keep your pets away from any spills until you rinse it off.

Never mix DOT-3 with DOT-5 because it turns to gum inside your brake lines. How can you tell which kind you have? Take a few drops from your reservoir and put it in a dish of plain water. If it dissolves, you have DOT-3. If it stays together in a ball you have DOT-5 which is silicone-based. - Dave

[YellowRose]

'60 Stop Light Problem

I wanna tell you that since I have been on this Forum, I have been (and you have also) getting a Masters Degree in Automotive Repair! From people like Dave ~ simplyconnected, our illustrious webmaster, John Pizzi ~ jopizz, and soooo many more, to numerous to list! What an education one can get by just reading all the posts. As your Administrator, every day I READ every post made on this Forum, in EVERY sub-Forum, from top to bottom. If you are just sticking to reading the sub-Forum for the year of your Tbird, you are missing an education for sure! Read everything posted regardless of the sub-Forum! I never knew how to test to see if you have Dot-3 or Dot-5 brake fluid in your MC. Until Dave just told us how to do a very simple check to find out!

[Tbird1044]

Mike:
We still don't know if you manual or power brakes, and if you do have power brakes, does your car have factory AC? Ford used a different booster on AC cars.
Now, without knowing your brake setup, there is a spring on the brake pedal that is common to power and manual systems. I will attach a picture. The spring reference number is 2472. If this spring is broken or has become disconnected, the brake pedal will NOT return to its full position. On a friends car, this spring had somehow become disconnected, so we just needed to reattach it properly.
More to come when we know what brake setup you have.
Nyles

[simplyconnected]

Nyles, God love you. You are a great help to many on this forum. The picture you posted is a great hellp too. But, until we know what kind of system he has and until he follows the procedure in the Shop Manual we could be guessing until we're blue.

Another 'thing' that happens with (countless) newcomers is, they join, ask a question, then we never hear from them again. Meanwhile, you dig through your references and post great suggestions to help out.

Ray kindly posted for the new man but he may not know how to look up our answers or suggestions. I've found where someone asked the same question on a few sites, which is alright but he may not return here, especially if his problem is solved elsewhere. - Dave

[Dan Leavens]

Ray I agree. The wealth of knowledge that our members continue to share on this site simply amazes me. I too, read all forums and have learned several things about our beloved TBirds and the people that support it. Like I always say, who will listen, this is the best TBird site on the planet

[Tbird1044]

Dave:
No probs as I had the pic saved from a previous post. If he does have p/b, I think you know where I was headed with that one.
Nyles

[Guest]

'60 Stop Light Problem

Sorry for not enough info in my first post !! It's power brakes without A/C. Complete system has all new parts except Power Booster. Car has 55K original miles. Thanks, Mike

[simplyconnected]

...If power brakes, the setup procedures are covered in your Shop Manual on pages 10-12 and 10-15. - Dave

Did you refer to your shop manual as suggested?

[Tbird1044]

Mike:
One thing you might try is disconnecting the vacuum hose at the power brake booster after the car is parked and then see if the brake lights still come on. There is a check valve in the vacuum line from the engine and also a tee that connects the power brake booster to a reserve vacuum tank located in the left front fender. If the brake lights don't come on after doing this, then the p/b booster and adjustments should be checked. If the lights still come on, then it is time to check the hydraulic side of the system and determine why pressure is building in the system. BTW, do you still have the factory single acting master cylinder?
Nyles

[Guest]

'60 Stop Light Problem

Thanks Nyles !! I'll try the things you suggested. Yes it still has the single master which I rebuilt and the inside bore was perfect. Mike

[YellowRose]

'60 Stop Light Problem

Mike, you have not said if you own a Shop Manual for your Tbird. If you do not have one, you need one to help you troubleshoot this. You can get one from any of the many Tbird parts houses. They are all listed in the Advertisements Forum...