Brake pedal hard

[Slacker809]

The other day pedal was sagging when I got to work and causing brake lights to stay on. I pumped the pedal 2 or 3 times and held pedal up and it stayed up. When I got in truck after work pedal would only move about an inch but it stops fine. It doesn't feel like brakes are dragging and I can't smell anything. What would cause it to stay that stiff and have so little travel? I've pumped brakes before and it has never stuck. I have drum brakes all the way around.

[idaho_cowboy]

Sounds like you're due for some brake inspecting. Could be wheel cylinder(s) going out. Could be master cylinder as well. Regardless you don't want to chance it. When it went to the floor, that was a first sign of a leak, or air in the system.

- Joseph

[calipilot227]

Air in the system? Try bleeding it.

[radioactivelarry]

The other day pedal was sagging when I got to work and causing brake lights to stay on. I pumped the pedal 2 or 3 times and held pedal up and it stayed up. When I got in truck after work pedal would only move about an inch but it stops fine. It doesn't feel like brakes are dragging and I can't smell anything. What would cause it to stay that stiff and have so little travel? I've pumped brakes before and it has never stuck. I have drum brakes all the way around.

Do you have a power booster? Mine went bad on my T-Bird and it caused the booster to apply the brakes and run down the battery because the brake lights were on while parked.

I had to remove the master cylinder from the booster to move the car because the brakes were stuck on!

If you don't have a power booster take a close look at the master cylinder and make sure your parking brake is not stuck on

[ultraranger]

Check the fluid level inside the MC. The fluid should be within 1/4" below the top in both reservoirs. If you have power brakes, look at the back of the MC where it bolts to the booster and see if this area it wet with brake fluid. If it is, and if the fluid is leaking out the back end of the MC and over into the booster, it's new booster and MC time.

If you have manual brakes, from inside the truck, look and see if brake fluid is leaking out the back end of the MC and down the inside of the firewall. If it is, it's new MC time.

If there are no leaks to be found in the entire system, then the MC is bypassing internally. --pressure is simply returning from the piston chamber, past the seal(s), through the compensating port and right back into the reservoir.

[Spinner01]

l'm currently having a similar problem. I had a spongey pedal that required pumping to build pressure. I found no leaks at the wheels, lines or the MC. I bled the lines at all wheels and a very small amount of air was found at the drivers rear. The spongey pedal persisted - basically no change. I then adjusted the vacuum booster rod (counter clockwise) and got a hard pedal. While adjusting, I heard vacuum escaping from the booster through the rod opening. At this time the pedal was actually too hard with almost no travel, so I adjusted it again clockwise about 1 full turn. All was good at the pedal for a day or so, then the pedal became too hard again. I adjusted it clockwise again about a half turn -- heard air escaping again -- reassembled and then had a spongey pedal. Adjusted counter clockwise again a half turn or so and the pedal is good again. But likely not for long. I'm thinking of replacing the booster. Does this sound reasonable? (1968 F250 Camper Special - all drums).

[colnago]

The other day pedal was sagging when I got to work and causing brake lights to stay on.

The rear brake lights, or the dash brake light? If the dash, then you have a pressure differential between the front and the rear. If the pedal isn't going back, possibly a broken return spring. Can you lift it manually? What do the levels look like in your MC? Have they ever run dry?

Joseph

On edit, what year truck? The '67 is different from the others (even the switch for the brake lights).

On second edit, I recently replaced the front brakes, booster, and MC. After the change, i found that the pedal moved to the floor. Bottom line, I hadn't adjusted the post between the MC and booster properly. After adjusting, life was good. However, it just gave me soft brakes before the adjustment. The pedal still returned all the way when I lifted my foot.