Soft brakes......

[Ronin1082]

Brakes are fully functional but are a little soft. Roughly 70% on the brakes all around. When rolling and come to a stop, it's like an air bubble in the line. Then I give it a pump or two and have full pressure. I was thinking master cylinder, but then was told it could be the booster since at a stand still I can pump them up but then soften up a little. So any history or ideas? Master cylinder or booster? Btw....No leaks that I've seen.

 

[KidVermicious]

Brakes are fully functional but are a little soft. Roughly 70% on the brakes all around. When rolling and come to a stop, it's like an air bubble in the line. Then I give it a pump or two and have full pressure. I was thinking master cylinder, but then was told it could be the booster since at a stand still I can pump them up but then soften up a little. So any history or ideas? Master cylinder or booster? Btw....No leaks that I've seen.

If you're not losing fluid, and pumping the pedals stiffens them up, it's likely a vacuum leak in the booster or hose.

 

[BlackCat914]

Our trucks are notorious for soft brakes. If you pump them when idling and the pedal gets hard, it's because you're drawing all the vacuum assist faster than it can be replenished, essentially loosing the "power" portion of the brakes.

 

[tyr0981]

hmmm have a similar issue, after the brakes "warm up" the peddle is about 3 inches (guessing) further from the floor then when started cold... pumping it helps also... otherwise the pedal goes about 75% of the way down.

I've replaced the pads/rotors/drums several times it's never improved, or gotten worse... had the entire system drained and bleed also, no change...

 

[Ronin1082]

I'm thinking of just replacing the MC & Booster. Let you know what happens.

 

[nevada]

Brakes are fully functional but are a little soft. Roughly 70% on the brakes all around. When rolling and come to a stop, it's like an air bubble in the line. Then I give it a pump or two and have full pressure. I was thinking master cylinder, but then was told it could be the booster since at a stand still I can pump them up but then soften up a little. So any history or ideas? Master cylinder or booster? Btw....No leaks that I've seen.

the rear brakes need adjusted.

 

[tyr0981]

the rear brakes need adjusted.

i though so as well and replaced the shoe's, adjusted the hand brake cable, made no difference at all....

 

[nevada]

I'm thinking of just replacing the MC & Booster. Let you know what happens.

unless the pedal is HARD, the booster is likely fine.
a soft pedal could be air, or a bad mc.
a low pedal will usually be rear drums out of adjustment.

i though so as well and replaced the shoe's, adjusted the hand brake cable, made no difference at all....

MOST of the time, a bad mc wont pump up to a higher pedal.
if all else checks out with the rear brakes, and fully bled, and the pedal is still low, or soft, the mc is bad.

if the pedal pumps up, keep your foot on it, and count to 60.
if it drops, the mc is bad, OR you have a leak.

 

[Ronin1082]

I also was told about the rear needed adjustment. That is some I need to check also. Thanks for reminding me!