How to R&R Brake Light Switch 63 Bird

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ricklove
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Re: How to R&R Brake Light Switch 63 Bird

Post by ricklove »

Brake lights inop again. The 1st replacement switch (ACDelco) didn't work at all, then I used a NAPA Echlin switch and they worked for a couple of drives before stopping again. Replaced with another Echlin switch and they again worked for a couple of drives before stopping again. Is it more likely that there is enough "trash" in the brake fluid reservoir that's causing these issues vs electrical problems? Thanks!
Cliff Rankin
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Re: How to R&R Brake Light Switch 63 Bird

Post by Cliff Rankin »

Can you pull off the switch and take something like a drill
Bit ( back side of bit ) and check it with a meter ? Continuity check. How about getting someone to push down on the pedal without letting up and see what the fluid looks like.
Kind of like bleeding a wheel cylinder.
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RedBird64
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Re: How to R&R Brake Light Switch 63 Bird

Post by RedBird64 »

Given the failure mode, I suspect the current is just too much for the switch. The old ones were almost certainly better made than the new ones and they would last. I also noticed that some new switches have a disclaimer that they are not approved for use with silicone brake fluid so if you use that stuff, it may be your problem.
Otherwise you may be able to get an NOS part* but sans that, you might want to consider adding a small relay to take all the load off the switch.

Good luck!

Scott

*NOS part :shock:
https://www.ebay.com/itm/NOS-OEM-Ford-1 ... Sw9Z1aYQHC
1964 Coupe Wimbledon white/Rangoon Red w/black int. Owned for 42 years. It was my folks car before that (second owners). VTCI # 12013.
Cliff Rankin
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Re: How to R&R Brake Light Switch 63 Bird

Post by Cliff Rankin »

Scott brings up a good point on brake fluid. I just recently replaced mine when I changed to a duel master cylinder.
I purchased Mine at carquest with my master cylinder.
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Karl
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Re: How to R&R Brake Light Switch 63 Bird

Post by Karl »

G'day.

You can have a failure rate with aftermarket parts but you seem to have too many.

Sounds like something else is at fault. As mentioned earlier, the brake fluid may be doing something.
Or have you checked the wire connections where they plug onto the switch. maybe the wire has broken from the metal terminal underneath the rubber insulation. When you wiggle them they may make a connection. Get another piece of wire with the same bullet connections and make a jump wire. There should be a constant source of current even when the ignition switch is off. Plug the jump wire into the female connections and make sure they hold tight, give it a wiggle to see if the connection underneath the rubber insulation is broken. Have somebody else watch your stop lights to see if they flicker on and off.
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ricklove
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Re: How to R&R Brake Light Switch 63 Bird

Post by ricklove »

Using only DOT3 brake fluid. Has anyone out had success using a particular brand (p/n) brake light switch for a 1963 TBird that works all the time? As previously stated, the ACDelco did not work at all, and each of the previous two NAPA Echlin SL134 worked for a few drives and stopped working. The 2nd one did work one time for a second or so last night after I cleaned out the black sediment from the reservoir and replaced the fluid.

For anyone that has replaced the stock brake light switch with something else monunted somewhere else, please provide list of what is needed from 19xx model xx. Thanks!!
MN63Tbird
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Re: How to R&R Brake Light Switch 63 Bird

Post by MN63Tbird »

Rick, I ordered my brake switch from Larry's 5 yrs ago and have had no problem, however, I had changed out the master cylinder also at that time. Based on the comment that you found black crud in the reservoir and that may have plugged the switch, I would highly recommend changing out the master cylinder especially if you have no idea when the last time it was replaced. Typically the crud in the master cylinder is more like rust from moisture interacting with the iron walls of the reservoir. That Black crud can also get into the brake lines and that is not a good thing since they are so small on the Tbird. Also if you dont know how old the master cylinder is, the plunger in the cylinder has a black rubber like seal on the end and has a black rubber cap that provides pressure to the brake lines. That seal will degrade over time and if it does you have no brakes. Not a pretty sight. We hope that is not your source of black crud.

The failure of the two brake light switch is a little baffling. That is why a number of others on this forum have been pointing to other sources. The brake light switch is a pressure switch. When pressure is applied by master cylinder to the the brake fluid , the fluid pushes the bellows forward in the brake switch forcing two contacts to meet. In this case it completes the circuit to allow 12volts to travel to the tail lights. Its sort of like your door bell button. You press the button and it makes a contact that completes the circuit to your door bell. Its a very simple mechanical action that has been used for decades. The switches may have been bad, but it begs to do more trouble shooting and look at the master cylinder or the wiring as a potential source of the failure.

MN63
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Re: How to R&R Brake Light Switch 63 Bird

Post by ricklove »

MN63TBIRD: The master cylinder appears to be "as new". The previous owner had the car for a tad over 5 years, but offered no receipts when I purchased it.
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Re: How to R&R Brake Light Switch 63 Bird

Post by MN63Tbird »

Rick Someone once said the definition of insanity is doing the same thing over and over and expecting a different result. Four switches and none work. Before this drives you insane I would recommend a different approach. ::? work upstream from the brake switch to the brake fluid and power to see if there is an ongoing cause. Again having black crud or any crud in the Master cylinder reservoir is NOT a good thing!

Option 1. Replacing the master cylinder, seal and a new brake switch is about $100. All the Tbird vendors carry them. Takes about a week to have it delivered to your home. Time to do so is an afternoon. Ease- relatively simple to unbolt everything. Mess- medium- need to be careful on spilling brake fluid on painted surfaces. Reinstall- medium difficulty. Need to align up the unit and refill brake fluid hoping not to get air in the brake lines. All this is outlined in the service manual. Its a good learning to understand the brake system and failure modes when you look at the internals of the master cylinder. I never trust the PO on the brake system. It is the first area that I rebuild when I get a car. I then know exactly how old everything is and what condition. You are going to try and stop a 2 ton car all the parts better work every time.

Option 2 . Check out the wiring- Again under $100 for a good continuity meter, wire clips and a wiring diagram. Ease - simple mostly checking continuity or is there a continuous wire or connection between the contacts for your meter. One probe on one end of the wire and one on the other. An audible setting allows you to check without having to look at the meter. The wiring diagram helps you find where the wires go and by the color which is which. Pull the wiring socket off the end of the switch. Connect one probe to one end and the other to the other end. Press the brake and your continuity meter should beep if it is working. You can also check to make sure it is getting the proper voltage with the probes. One to the switch one to ground.

In any case you are going to need the service manual, a good set of wrenches/sockets, wiring diagram and a continuity-volt/ohm meter in the long run. There will be plenty of more challenges with the 56 yr old car but it can be a fun learning experience.

MN63
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Re: How to R&R Brake Light Switch 63 Bird

Post by ricklove »

MN63Tbird: When I purchased the car a month ago, all electrics worked except the clock and the brake lights. When I got it home, I installed an ACDelco U855 switch that did not work - period. Then I installed a NAPA Echlin SL134 switch - it worked for a couple of drives, then stopped. Installed another Echlin switch and it worked for a couple of drives, then stopped. The next day, it worked again; once; then stopped. That's when I discovered the brackish brake fluid; "sucked" it all out, cleaned the blackish film from the master cylinder, and refilled with new DOT 3 fluid. The exterior of the master cylinder looks as new. I'm going to use a multimeter tomorrow and go from there. Thanks
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RedBird64
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Re: How to R&R Brake Light Switch 63 Bird

Post by RedBird64 »

Without actually flushing the MC and bleeding the brakes, some of that nasty fluid is going to remain down in the passage and make it way into any new switch.
It's also good for the entire brake system to get the old fluid out new stuff in.

Scott
1964 Coupe Wimbledon white/Rangoon Red w/black int. Owned for 42 years. It was my folks car before that (second owners). VTCI # 12013.
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Alan H. Tast
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Re: How to R&R Brake Light Switch 63 Bird

Post by Alan H. Tast »

Forgive my bluntness, but I think it's time for you to move on to flushing out the old brake fluid in the system, rebuild the master cylinder and wheel cylinders for good measure, install new fluid and bleed the brakes. You probably have gunk in the brake system if the fluid hasn't been cleaned out recently. If you've ever taken apart an old master cylinder or brake cylinders that have sat with fluid in them for several decades you'll find gunk, rust and a gooey mess. More than likely you're filling the switch with goo, which won't let it operate properly.

Remember Albert Einstein's definition of insanity: repeating the same process again and again expecting a different result.
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Re: How to R&R Brake Light Switch 63 Bird

Post by tbird »

Get your self at least a quart of denatured alcohol, open all the bleeders one at a time with a hose attached to them and a have a container to catch the crud that you are going to get out of each line. Would suggest that you get a helper to pump the brake pedal as each line and wheel cylinder is drained of the old fluid. When there is nothing left in the system fill the master cylinder with the alcohol and pump it out at each bleeder valve until it runs clean and clear when that happens you are now ready to install a new brake light switch and new fluid. At this point the system should have come clean if not Do a complete brake system inspection and replace corroded lines, hoses, wheel and master cylinder. As others have told you here you don't get 4 brake light switch's in a row that are no good.
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ricklove
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Re: How to R&R Brake Light Switch 63 Bird

Post by ricklove »

Thanks to all for the input! I was trying to keep it as simple as possible, but my failed efforts (and your input) has forced me to now "do it correctly". Will probably tackle it within the next few days. A fair amount of documentation came with the car (none from the previous owner of 5 years) that shows this car has only been driven 6,501 miles from 09/23/03 to present. I've driven it over 400 miles in the past month of my ownership. Thanks again for all the input!!!!
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saenzm
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Re: How to R&R Brake Light Switch 63 Bird

Post by saenzm »

ricklove, not sure if it helps in your case but I found that my taillights were unreliable due to a bad ground in one of them. The previous owner had installed the wrong type of socket. There's a lot of great advice in this thread and i can definitely concur about the all-important shop manual.

On a side note, pay no attention to the quotes about "insanity" LOL. Einstein never even said that; it's just something people like to repeat.
-migs

1962 Hardtop ...perpetual WIP
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