Packard Forum Index » Post-War (1946-54)

I am noticing that my brake lights on my '54 Clipper Super tend to stick in the on/illuminated position when I exit the car. I have power (Easamatic) brakes. I have to get back in and pump the brakes a couple times and that seems to fix it..starting to take a couple tries to fix it that way. Is my brake light switch failing, or do some contacts just need to be cleaned up?
Please let me know what you think. Thanks Again!

Could be switch and that is inexpensive to replace but next time it happens, before doing anything else see if you can pull the brake pedal back any by hand and see if the light goes out. If the power piston is sticking so the hydraulic piston is staying just shy of rest position and the compensator port is still closed, enough pressure could build up due to heat to activate the switch.

Howard, sounds like you have ridden this carousel a couple of times before. Thanks again for all your knowledge and assistance.
Warren

This is like deja vu all over again! While it has not been doing so lately, my '55 Clipper had a problem during warmer weather with the brake lights staying on, especially when I was stopping in reverse. I haven't had a problem with them lately, but it's been so cold for so long, maybe this issue is on ice!

Howard...one more thing. If it is the heating issue and not a malfunction switch, is there a mechanical remedy..or just wait for the brakes to cool off and let the lights go out on their own without my intervention.

If the piston is sticking and you can actually pull it back maybe 1/8-3/16" or more and the light goes out then something is binding the linkage or something is happening in the vacuum side of the power unit. Could be mechanical bind, carpet pushing the rod off center or the like. If in the unit, could be old dry lube on the piston leather, a weak return spring, or worst case the seal is allowing fluid to be sucked into the vacuum side and it and the grease are mixing into a gummy sticky mess. Any of those should be looked at before it gets worse.

If you cannot pull the piston back anything more than just a smidge then all is OK and if light is still on, most likely the switch is getting tired. If you are running silicone fluid, that seems to be a destroyer of switches.

Hopefully Ross will see your post and have some other suggestions.

Howard..I believe I may have solved the mystery of my brake lights sticking in the on position. A while back, I replaced the circular rubber grommet seal on the neck of the screw-in master cylinder fluid reservoir cap. The seal appears to have been just a tad too big, so I seemed to have been getting a tiny bit of fluid leakage from the cap. Also, I believe the oversized seal was causing a loss of pressure integrity in the system. I believe this loss of back pressure was causing the brake piston and pedal NOT to return to the neutral/off position when foot pressure on the brake pedal was removed. With the original rubber seal installed on the neck of the reservoir cap, no leakage or 'sticking' of the brake lights is occurring. PS..this original circular rubber grommet/seal on the neck of the reservoir cap is a bit checked and worn. Do you know where I can get another one of these, or should I just go to the hardware store and try for a closer match? Thanks again for all your help and suggestions.
Warren

Don't forget the cap is vented to prevent the reservoir from pressurizing. You should find a tiny vent hole on one of the corners of the wrench square - make sure it's clear.

When I needed a new cap gasket I got a copper O-ring of the right size from Restoration Specialties.

Glad you found the problem but think O_D has the answer with the vent. Can't quite picture how the ring you bought would block it so would be interested to learn how for the next time. That would have the same effect as if you had the piston sticking -- the fluid would still build up pressure from the heat but instead of pressure being trapped in the cylinder, it is trapped in the reservoir which is open to the cylinder when brakes are relaxed.

Hmmmm..I will check out the vent whole in the wrench square and get back to you. Thanks again for your thoughts!