1959 Parking Brake Alarm Unit

[Joe M.]

Prior to installing the unit in my car, I wanted to dry run it with a 12 volt battery. When I grounded the bulb to (-) side of 12V battery, it started blinking. I assumed it would not blink until the switch was engaged by the spring steel clip (parking brake pin pressing down on the clip). When I push the metal clip down by hand, it stops blinking.

Maybe I don't know how it is suppose to function. They way it is working now, it will always blink until the emergency brake lever is pulled back to engage the brake and then it will stop blinking. What am I missing here?

[Richard M.]

Re: 1959 Parking Brake Alarm Unit

Joe,

It's a NC(normally closed) switch. When the park brake is released, the pin on top of the shaft depresses the switch(upwards) to open the contacts, shutting off the light. When you apply the brake by pulling the handle, the pin moves away from the switch, releases the brass flat spring and the circuit closes, lighting the light. Yours is working correctly.

Rich

[Joe M.]

Re: 1959 Parking Brake Alarm Unit

Thanks Rich. Sometimes been testing is not the best way. am having no luck finding a 6 candle power bulb (#90). A #57 did not work well. What bulb do you use?

[Joe M.]

Re: 1959 Parking Brake Alarm Unit

If I understand your description Rich, I need to mount the switch at the point where the released brake rod is all the way in and the pin on top is depressing the switch, correct? Then when I pull the handle to set brake, the pin moves off the switch lever and the light starts blinking. In my mind, I had it just the opposite, Normal Open.

[Richard M.]

Re: 1959 Parking Brake Alarm Unit

Correct.

Yes you were thinking the opposite.

edit.....Sorry I can't recall the bulb installed, but mine has the separate Tungsol flasher and a non-flashing bulb.

[Joe M.]

Re: 1959 Parking Brake Alarm Unit

I bench tested the entire unit with a #53 bulb and it worked flawlessly. However, when I installed the switch on the brake rod, the top of the rod pushes on the spring clip part of the switch just enough to contact the pin and opens the switch. In that position, the switch is always open and the bulb will never flash. Attached are a couple of photos of the switch. There is something wrong with the configuration, but since this is the only switch I have ever seen, I don't know what is wrong. The small tab at the back of the switch probably has some purpose, but I don't know what it is. Any suggestions?

History - The switch was made by John W. Hobbs Corp., Springfield, IL. Hobbs made the first electric clock for a car in the 1930s. Operated at the same location from 1938 until 2002 when the factory closed by the owner, Honeywell, and the work moved to Juarez, Mexico.

[Richard M.]

Re: 1959 Parking Brake Alarm Unit

Joe, Glad the #53 bulb did the trick.

Check 12v at the fuse block. You should have a 10A fuse in the 3rd from top position marked "BACKUP"_____"BRAKE AL", and the brown wire plugged into the "BRAKE AL" terminal. Only powered with IGN on.

You might have to bend the brass piece a little closer to the plunger(barely touching) on the switch before mounting. That small tab is not important. I think it was a mfg/design error, as you'd think the big brass flat spring should fit above it but if so, the switch will always be open circuit as it'll keep the plunger up always.

I recall my switch was always a little sensitive, and I had to repair the brass piece a long time ago as it was worn out and got stuck in the rod once. My pic on the TDB shows the solder job I had to do on it. Try mounting the switch with the screw loosely, then move it in the right position and tighten it up. I suspect you'll have to fiddle with it a little to get it adjusted properly. Put a little grease on the shaft pin so it doesn't wear out the brass spring piece.

Rich

p.s. enclosed a few pics of a 61-62 switch(same thing except wiring) which may help.
DSCN0125.jpg DSCN0126.jpg

[Joe M.]

Re: 1959 Parking Brake Alarm Unit

When the brass piece pushes on the switch pin 1/100", the switch is open. The location of the brake rod pushes on the spring piece 1/100" when it is installed; switch open all the time. The switch pin appears to extend to far down from the switch, but it probably is the proper length. If it was 1/32" shorter, the brass piece would not activate the pin (switch open) when it is installed on the rod.

At this point, I don't know how to tweak the brass piece so that the switch is closed when it is installed on the rod. I don't want to bend the brass piece. I think it is supposed to be straight as it comes down from the top of the switch.

[Christopher R.]

Re: 1959 Parking Brake Alarm Unit

Does anybody have any experience in rebuilding or repairing these switches? Anybody ever take one apart?

[Richard M.]

Re: 1959 Parking Brake Alarm Unit

Joe,

Pic from ebay(BTW $325.00!), looks like the plunger length like on yours, so it's normal I guess. This is 61-62 as the harness isn't setup for the TungSol flasher but same switch.
$(KGrHqV,!h8E9dvSPGlWBPorZq6qhg~~60_12.JPG

Also from ebay, one that's all apart.....broken, but to see what it looks like inside. Also note how the flat spring brass piece is worn. That's what happened to mine also. The pin is really worn too, which would raise the release point.....Hmmmmm.
$(KGrHqN,!rUFDfWli9PnBRBtKR3,Gg~~60_57.jpg $T2eC16h,!w0E9szN,9h6BRBtKi6jzg~~60_57.jpg $(KGrHqJHJEUFD)v1KgnNBRBtKoB)kg~~60_57.jpg

You never had a PB alarm switch mounted before, correct? Here's what I'm thinking. Could it be possible that the actuating/stop pin on the brake lever shaft is too high? I wonder if they had to file that down a bit to get these to work when this option was installed.

Only other thing I can think of is the diameter of the clamp area of your switch. Did you actually try mounting with the screw? Maybe that might squeeze it enough to raise it.

Rich

[Joe M.]

Re: 1959 Parking Brake Alarm Unit

I got a really good deal for $225 and the brass piece is worn, but not even close to wearing through it like the photo you posted. As far as I know, my car did not have a PB alarm. I mounted the switch on the brake rod. The actuating/stop pin is not the problem. The switch is in the open position as soon as I mount it to the parking brake notched rod; meaning the brass piece is being pushed up into the switch pin by some part of the brake rod. This condition is occurring when the actuator/stop pin is not in contact with the switch assembly.

Another example of what I thought would be a simple installation, but I should know by now that there are few simple installations.

[Joe M.]

Re: 1959 Parking Brake Alarm Unit

Lift up the tabs holding the switch guts inside the switch housing and everything will pop out; literally, since there is a spring inside the housing. The only moving part is the spring that pushes down on the pin to close the switch. Christopher, what part of your switch needs rebuilding?

[Richard M.]

Re: 1959 Parking Brake Alarm Unit

Joe,

Yes a 5 minute job that takes hours, I know what you feel. Frustration. Okay, we'll figure this out somehow.

Take some detail photos of the mounting area of the shaft(top & sides), and then mount the switch and take a few shots from different angles, with the PB rod released and also engaged.

One possible fix is to file the switch plunger pin shorter to raise the actuation point, but don't do that........yet.

Other thoughts......
-When the switch is mounted pull up on the switch wires a little bit to see if that does anything. Loose?
-Make sure there's not thick paint buildup at the PB tube switch mount area. That could change the height.

Rich
p.s. Chris.....Good question. As you can see in those pics I found you can release the little tabs to get inside the contacts, but it looks very delicate. I don't see how the metal switch barrel is fasted to the clamp assembly, maybe swedged internally.

[Joe M.]

Re: 1959 Parking Brake Alarm Unit

I snugged up the switch on the PB rod and moved it until the PB alarm light blinked; then tightened it down. I made one mistake by installing the switch too far forward with the actuator/stop pin back inside the switch. When I pulled on the brake handle, the actuator/stop pin grabbed the brass piece and bent it, but did not break it (see attached photo). I move it back further and tightened it down. The brass piece is now slightly bowed up in the front/top, but still works. Update - after 90 minutes, went back out to see if it would still work, it did not. Loosened switch again, moved it around until light blinked, tightened it down and it worked again.

I will no longer release the brake and let the brake rod slam the back of the rod housing. I think it is better to release it slowly and let it go to the back of the rod housing.

[Richard M.]

Re: 1959 Parking Brake Alarm Unit

Sounds like you got it fixed. Like I mentioned you need to fiddle with these switches a little to get them to work. Not the best design. But when they work it's a good indicator. It's easy to try to drive away with the park brake set. I've done it myself, then see the red light flashing at me to remind me!