Packard Forum Index » V-8 (1955-56)

I have a '56 Clipper custom, I had it in for spring service and they did routine checks, oil change etc. They noted a failed brake light switch and exchanged it. I picked the car up and drove it home about 45 minutes driving. when I got it home the brakes seemed stuck on, and the brake lights at the rear were on. I backed the car into its spot, and it didn't really want to move of course, I disconnected the battery as the brake lights were on with the car shut off. The car sat for around an hour when I reconnected the battery the brakes had released. I bought the car in '16 and it needed a full brake job. The treadle vac was redone by Ed Strain, so my concern here would this likely be due to a failing treadle vac, or would the replacement of the brake light switch have caused this?

Brake light switch will not affect this unless perhaps you have a retrofitted mechanical switch which is holding the pedal down slightly. Not likely.

More likely the pedal is not returning completely. Next time this occurs lift the pedal with your toe and see if the dragging clears. This can be caused by too much friction of the power piston inside the booster, a leaking poppet valve that is allowing vacuum to the booster even when you are not braking, or just a misalignment of floor mats and pedal holding the pedal down slightly.

But first see if you can clear the condition by lifting the pedal.

Thanks for your suggestion, I went back to where the car is parked and started it and it ran for around 20 minutes, initially there was no problem, but once the temp was up to around 170, it reappeared, I've added gauges so I can monitor the basics. I was pressing on the brake periodically to see if that would cause it to happen. I'm just going to let it get hot and leave the pedal alone on the next try and see if it happens with out brake action. If it reoccurs I'll try pulling up on the pedal as you suggest.

I warmed the car up and left the pedal alone, that seems ok the brake lights dont come on, I checked the free play between the back of the pedal and the actuator rod for the master cylinder and that seem pretty tight but there was a bit of free play, as the car warmed up it seemed to be a bit less. I took a look at the pedal hanger and the side nearest the door was really loose, it could move around and I couldn't view the mounting because there was a cardboard vent cover and carpet in the way but I'm guessing that the mounting hardware is underneath all that inside the car, before I take it apart I'm wondering if you can confirm that???

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Here is what is under the pad. The bolts that hold the left pedal bracket are double purpose and also are used to partially hold the emergency brake mechanism bracket located on the engine side of firewall. Both sets of bolts have nuts on the engine side but right side bolts only hold the pedal bracket.

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I pealed the carpet back and found a 1/2 nut rolling around loose, when I felt around under the padding the bracket seemed to be on a 1/2 stud with no hardware tying it down.

I assumed the lose bolt was the reason the whole thing was floating around loose and put the bolt back on the stud and was able to get a ratchet up on that and tighten it down which helped some.

The lower hole in the bracket had nothing there which would conform to the photo in that it needs a 1/2 (??) bolt I guess.

Not sure exactly whats going on here as I cant really see whats behind all the cardboard and padding.

After warming up the car and it seemed ok but then the brakes lights came on after pumping the brakes some. In this case lifting the pedal caused the lights to go out so I'm guessing the clearance between pedal and the actuator rod is tight.

Based on you photo (thanks very helpful) seem I need to get a cap sscrew to fit the lower hole in the bracket but need to know if you can tell me what thread that would be?? 1/2 inch 9/16 etc

The service manual (Pg15 in the Brake section) says the rod can be adjusted, not sure if this has a direct adjustment or there meaning that the position of the brake pedal can be changed somehow.

I'm thinking if I get the bracket solidly mounted and the correct clearance between the pedal and the push rod that things should work properly, does that make sense??

Thanks for the help ...