Brake Light broke!

[Harvie]

Hello all, just noticed that the brake light on my 1947 Chrysler New Yorker has quit working. It is the original one in the centre of the trunk lid. I removed the bulb and checked it - working. I used a small wire brush on the area were the bulb receptacle comes in contact with the lid to try to ensure good ground - bulb still will not work when installed. Any advice about how to ensure good ground or should I take the next step and presume that the switch has failed? If it is the switch then any advice on the replacement procedure? I saw a video on youtube produced by a gentleman who was replacing the brake light switch on a 50's model De Soto and he said that if a vintage Mopar is using silicon brake fluid then the switch will wear and and fail quite frequently. He therefore replaced the pressure switch with a switch activated by the brake pedal arm - has anyone here ever heard of such an issue? Also, since I may have to replace the brake light switch I thought perhaps I would go further and get some discreet LED under bumper turn and brake signals added - is this worthwhile? Can anyone recommend a good LED signal kit that they are happy with?

[Reg Evans]

To test your brake light wiring just put an alligator clip on both posts of the brake light switch. If it lights you know what to do.

[greg g]

Probably the hydraulic switch acting up.  Locate it pull the wires and touch the together if the light lites 

Its the switch.

[Norm Knowles]

Just did this on my 48 Dodge and did the same as suggested by Greg g and found the switch defective.  Replaced it and all works now.

[Norm Knowles]

Also found that the last eight inches of wire to the switch were in very poor condition so spliced in new pieces.

[Harvie]

Thanks you gentlemen - and has anyone gone to the  LED under bumper signal kit? Is it true that the switch is adversely affected by silicon fluid?

[Harvie]

Sorry, but I also wanted to know if you must bleed the brakes after replacing the switch.

[Don Coatney]

1 hour ago, Harvie said:

Sorry, but I also wanted to know if you must bleed the brakes after replacing the switch.

 

I replaced the switch on my D-24 and no brake system bleeding was required. If I recall I bought the switch on Amazon. 

 

 

[Harvie]

Thanks Don! I always really appreciate your help. 

[Dad-Par]

Hello Harvie:

Speedway Motors has that mechanical arm brake light switch, Part # 91031306.They also carry Painless Wiring 80174 Pressure Brake Switch with Pigtail, 1/8 NPT,  Part # 91031307.  It provides a snap on connector w/ pigtail.  Mac's Auto Parts (Early Ford Parts) (part of Ecklers - more Chevy/GM oriented) carries same Speedway brand mechanical arm switch, Part # 13480-UNIV, at bit higher cost although Mac's also carries more of a weather boot connector w/pigtail, Part #: 32-11501-1 for either mechanical lever or standard pressure switch.

John

[Don Coatney]

I installed this mechanical switch on my P-15.

 

 

[Harvie]

Thanks Don and John. I just ordered the pressure switch from Bernbaum and await delivery. Looks like the pressure switch is located at the highest point in the brake system so bleeding will be unnecessary as Don has suggested. Just to be safe perhaps I should get somebody to slightly depress the brake pedal while I install the new switch in order to avoid any possibility of trapping air?

Also, I am wondering Don, did you install the mechanical stop light switch on your P-15 to avoid problems caused by silicon fluid (do you use silicon brake fluid?) or did the P-15 use a mechanical switch originally? Sorry but I am not familiar with that detail. Are you still using the pressure switch on the D-24? Any problems? Should I convert to a mechanical switch system?

 

Finally, still wondering if anybody out there has any experience with the LED signal system that I have been asking about.

 

Thanks again for the excellent advice and input I get here. I only recently got back into this hobby when I bought the '47 New Yorker a year ago, about 20 years before that before that I had "49 dodge and a '28 Ford for many years and apart from a small group of great local guys - most of whom are gone now - there was no resource like this site that you could consult. I always really appreciate the help I get here from great guys from all over the world.

[Don Coatney]

23 minutes ago, Harvie said:

Thanks Don and John. I just ordered the pressure switch from Bernbaum and await delivery. Looks like the pressure switch is located at the highest point in the brake system so bleeding will be unnecessary as Don has suggested. Just to be safe perhaps I should get somebody to slightly depress the brake pedal while I install the new switch in order to avoid any possibility of trapping air?

Also, I am wondering Don, did you install the mechanical stop light switch on your P-15 to avoid problems caused by silicon fluid (do you use silicon brake fluid?) or did the P-15 use a mechanical switch originally? Sorry but I am not familiar with that detail. Are you still using the pressure switch on the D-24? Any problems? Should I convert to a mechanical switch system?

 

Finally, still wondering if anybody out there has any experience with the LED signal system that I have been asking about.

 

Thanks again for the excellent advice and input I get here. I only recently got back into this hobby when I bought the '47 New Yorker a year ago, about 20 years before that before that I had "49 dodge and a '28 Ford for many years and apart from a small group of great local guys - most of whom are gone now - there was no resource like this site that you could consult. I always really appreciate the help I get here from great guys from all over the world.

 

I used the mechanical switch on my P-15 because I had the switch in my inventory and the pressure switch failed. I am not using DOT-5 in the P-15. I replaced the pressure switch in the D-24 as the original switch failed. I am using DOT-5 in the D-24 but I don't think this fluid had any thing to do with the switch failure.