Is it normal for brake pedal travel to decrease when pumped.

[Montana71-F100]

I have a 1971 F100 4WD with standard drum brakes. When I step on the brakes the first time, the pedal goes within about 4 inches from the floor and feel firm, as I pump them the pedal travel gets less and less. Is the change in brake pedal travel normal?

Thanks.

[cajuncannon03]

Bad MC or wheel cylinder. Check for leaks @ all wheel cylinders.

[fordman]

yes the master sounds bad or a leak elsewhere.

[Mancar1]

I agree with whats been said. I will add that you should never need to pump. While you are at it you may as well check the pads may be time to replace them.

[thorn1968]

So is the distance to the floor less each time, or does the pedal stop higher each time?

[70_F100]

Have you tried adjusting the brakes?

[Montana71-F100]

So is the distance to the floor less each time, or does the pedal stop higher each time?

The pedal stops higher each time.

I will add that you should never need to pump. While you are at it you may as well check the pads may be time to replace them.

I don't need to pump to stop the truck. I just noticed that if I stop and roll forward and step on the brakes again the pedal travels less each time until I hardly have to push the pedal down at all to stop it. The brake pads are fine.

Thanks for all of the input.

[71highboy]

Have you tried adjusting the brakes?

that was my thought

[Montana71-F100]

Have you tried adjusting the brakes?

It has automatic adjusters. I just tried backing up and stepping on the brakes several times and there is no difference. The roads are covered with snow so I may not be getting the resistance I need so I'll try again after the snow melts.

Thanks for the suggestions.

[fordman]

auto adjusters dont do enough to adjust the rear brakes. you have to manualy adjust them for proper performance.

[71highboy]

auto adjusters dont do enough to adjust the rear brakes. you have to manualy adjust them for proper performance.

[BRUTUS_T_HOG]

Have you tried adjusting the brakes?

It has automatic adjusters. I just tried backing up and stepping on the brakes several times and there is no difference. The roads are covered with snow so I may not be getting the resistance I need so I'll try again after the snow melts.

Thanks for the suggestions.

LOL. even before i broke them my auto adjusters have never worked satisfactory. to the point where the starwheel fell out and i lost brakes.. and no it wasn't on the wrong side

if the brake pedal is FIRM and doesn't sink then you need to adjust all 4 brakes. if it sinks then the master cylinder is probably leaking internally

[Montana71-F100]

Thanks everyone. I always thought the manufacturer knew everything! I'll adjust the brakes on a warm day.

[Mancar1]

Thanks everyone. I always thought the manufacturer knew everything! I'll adjust the brakes on a warm day.

Ya, I could use one of those warm days I have heard others talk about.

[Montana71-F100]

The weather here is nuts. It was about 15 below zero a few days ago, then a chinook came and It was in the 40's yesterday and the snow was melting then it started to rain. Snow and temps around zero are predicted by Monday.

In case you don't know what a chinook is, below is a definition from http://www.theweatherprediction.com/habyhints2/464/

WHAT IS A CHINOOK?

METEOROLOGIST JEFF HABY

A chinook is a wind most notable in the northern high plains that brings in drier and warmer weather. One of the main reasons for the change in the weather is the sloped elevation. When air moves from the higher elevations of the west it downslopes as it moves east. Since the air is downsloping the temperature and relative humidity of the air will change adiabatically. Sinking air warms at the dry adiabatic lapse rate. When this warmer air replaces a very cold polar air mass the temperature increase can be dramatic. Another name for the chinook is "snow eater" since the warm and dry air quickly melts and evaporates snow away that is on the ground. The air at the high elevations tends to be dry (low dewpoint). When air downslopes it dries the air even more since the relative humidity decreases. As the temperature of air warms as it downslopes the temperature and dewpoint diverge (dewpoint depression becomes greater). As the dewpoint depression increases the relative humidity decreases. The chinook is most notable in the winter in the northern high plains.