1950 buick brakes

[Guest 50bomb]

So on my 50 buick roadmaster the brake lights stay on. We thought maybe it was the electrical but we taped up any lil opening in the wiring so then it still would stay on. We changed the wheel cylincers still the same. The brake pedal seems to get harder to step down on. Do you think it may be the brake springs? Maybe that is what keeps the brake lights on. Sometimes it stays off but other times it will pop on.

[Rusty_OToole]

Those brake light switches aren't very reliable. Try changing it before you do anything else.

[Pete Phillips]

If the brake pedal is getting harder to push and the brake lights are staying on, it sounds to me like the pressure in the brake system is not being released when brake pedal is released. That either means the master cylinder is malfunctioning and/or one of the rubber brake hoses is blocked internally. The brake hoses may look fine from the outside, but they can be collapsed and blocked on the inside, not allowing fluid pressure to release. Fluid pressure is what activates the brake light switch, too.

In the master cylinder, there are one or two little pinholes at the bottom of the fluid reservoir, and they like to get plugged up with rust and crud (that's a scientific term!) if the fluid hasn't been changed in 50 or 60 years, or the car has sat up unused for many years. I've lost count of how many of those pin holes I have had to unplug in old Buick master cylinders.

Pete Phillips, BCA #7338

Sherman, Texas

1948 Roadmaster

1949 Super

1950 Roadmaster

1956 Studebaker Hawk

1958 Rambler Ambassador

1959 Mercury Park Lane

1959 Buick Electra

1962 Buick Electra

1963 Chrysler New Yorker

1963 Buick Wildcat

Edited December 18, 2009 by Pete Phillips (see edit history)

[F&J]

One way to tell for sure "if" the system pressure is not releasing, is to drive it a few miles, and then see if the brake drum/wheels/backing plates are way too warm or hot.

...or the next time the brake lights are stuck "on", then open the brake bleeders to see if there is pressure, and if the lights go out. (assuming this is a pressure type brake light switch) Also, these pressure switches don't survive long with DOT5 silicone brake fluids.

I'd do the test drive first.

[Owen_Dyneto]

Are you certain you have "free play" in the pedal? Lack of free play will certainly cause the problem you have, and will keep the brakes partially energized w/o any pedal pressure. This is because there isn't enough pedal travel for the piston to fully return and uncover the compensator port.

And I can confirm that DOT5 silicone fluid can really shorten the life of some hydraulic brake stop light switches.

Edited December 19, 2009 by Owen_Dyneto (see edit history)

[john compono]

where is the brake light switch located on a 50 Buick roadmaster ? thanks.

[Pete O]

Down by the frame in front of the driver in front of the master cylinder.  It's a pressure switch tapped into the brake line.  It can be seen with the hood up.

[john compono]

thanks found it!