Brake light switch warning

[greg g]

Just put a new NAPA Echilin Hydraulic switch.  When I put the old one back in the box to turn it in three months as defective, it's only a year old and they are warranted for three years, I noticed a small piece of paper in the bottom of the box.  It was a warning that this switch is not compatible with dot 5 or other silicon based fluids.  Just a heads up any one contemplating switching to the newer fluid after redoing brakes or doing a disc brake conversion.

[Doug&Deb]

That explains the problem I had with my D24 after I switched to silicon fluid. Live and learn.

[Merle Coggins]

I went through 5 or 6 Echilin brake switches from Napa before I gave up on them and purchased a Standard switch from Rock Auto. Napa switched would last a few months. They kept replacing them under warranty, but it was getting old. I had to keep a spare in the glove box so I could replace it on the road when I’d notice the brake lights not working again. The Standard switch has lasted several years now, and still going strong.

The last Echilin one I took out I cut open. The switch contacts were corroded black and wouldn’t pass electricity.

 

Edited July 26, 2019 by Merle Coggins

[greg g]

If I recall, I put this one in before we travelled to Detroit for the poc meet.  Didn't have the receipt, so at least I have one now to put against the next one.  Guess I will call our local mom and pop and see if they can get the Standard ones.  Echlins are heco in Mexico.

[desoto1939]

has anyone ever stated why the switch willnot work with Dot 5 fluid. I have been using Dot5 for over 32 years and have only replaced one brake light switch. I have used NOS switches and not new ones so I donot understand why they should fail. Possibly bad manufacturing process. The dot 5 is silicone and should not corrode the contacts.

 

Rich Hartung

Desoto1939@aol.com

[Merle Coggins]

Couldn’t add these photos yesterday, from my phone. Here is the Napa switch I opened up. Notice the black coating on the contacts. I don’t believe the type of brake fluid would have any affect on this part. It could have an affect on the diaphragm under the contact plate, depending on it’s fluid compatibility. 

 

A quick rub with Emory cloth cleaned it up pretty quick, but they shouldn’t corrode like that. 

 

This is the Standard P/N I am using now. This one is the spare I carry and haven’t needed since making the switch. 

 

 

The box has a “Made in Mexico” label. 

 

[Tom Skinner]

Correction:

Hecho en Mexico Senor! L.O.L.

[Dodgeb4ya]

NAPA= Crappa

NAPA Echlin used to be good quality.

Edited July 30, 2019 by Dodgeb4ya

[James_Douglas]

There was a Chrysler technical note, I have it someplace, that they went to a special switch to deal with problems of them going out. It turns out that the flow of the electrons was the problem. They came out of the switch that has a long and short post and was therefore polarity sensitive. When they went to 12 volt, I suspect it was not longer an issue.

 

I pulled my binder with the service bulletin...

 

[TodFitch]

1 hour ago, James_Douglas said:

There was a Chrysler technical note, I have it someplace, that they went to a special switch to deal with problems of them going out. It turns out that the flow of the electrons was the problem. They came out of the switch that has a long and short post and was therefore polarity sensitive. When they went to 12 volt, I suspect it was not longer an issue.

 

I pulled my binder with the service bulletin...

 

Interesting that the contact materials selected resulted in a switch that was polarity sensitive with respect to how long it lasted.

 

I wonder if any of the currently available after market switches are built that way. I sure didn't pay any attention to which wire went on which terminal when I replaced my switch about 10 years ago.

[James_Douglas]

3 hours ago, TodFitch said:

 

Interesting that the contact materials selected resulted in a switch that was polarity sensitive with respect to how long it lasted.

 

I wonder if any of the currently available after market switches are built that way. I sure didn't pay any attention to which wire went on which terminal when I replaced my switch about 10 years ago.

Don't shoot the messenger...should you not be out on the beach someplace :-)

[TodFitch]

4 minutes ago, James_Douglas said:

Don't shoot the messenger...should you not be out on the beach someplace ?

Wasn't trying to shoot the messenger. Just noting my interest in the information you made available.

 

And I was at the beach earlier today, water temp 70°F according to the information board on the pier. Pretty warm at the house as it is in the high 70s°F. Life can be tough when you live in a beach town.

[desoto1939]

I do not understand how the wiring would make any difference the current is completed when the brake fluid pushes up the metal contact and makes the circuit complete.

 

Rich Hartung

[Dodgeb4ya]

7 hours ago, TodFitch said:

 

Interesting that the contact materials selected resulted in a switch that was polarity sensitive with respect to how long it lasted.

 

I wonder if any of the currently available after market switches are built that way. I sure didn't pay any attention to which wire went on which terminal when I replaced my switch about 10 years ago.

NAPA and others still sell that special terminal switch.

Whether or not it is polarity sensitive is another question. Doubt it.

1953 and 54  MoPars use  female and male bullet terminals for correct polarity.

[TodFitch]

2 hours ago, desoto1939 said:

I do not understand how the wiring would make any difference the current is completed when the brake fluid pushes up the metal contact and makes the circuit complete.

 

Rich Hartung

 

My guess is that the choice of materials for the contact surfaces of the switch is such that any arcing when the switch opens doesn't damage things. But that is only a guess. And, as Dodgeb4ya noted, modern replacement switches may not have that feature.

[T120]

Tod,I believe you are correct.There is what I thought a good analysis of brake light switch failure on the MGAguru website. Basically because of the manner in which the brake light switch is activated, it is not a "snap" action and during the switch opening and closing arcing can occur. Damage to the contacts is cumulative causing the resistance of the contacts to increase over time...some contacts used in manufacture will last longer than others...