spongey pedal, parking brake light

[Four0Sport]

I've been fighting a spongey pedal all spring/summer. After bleeding the brakes are firm for a while then become soft/spongey again. The other night on my way home from work I noticed the brake pedal going farther to the floor and the parking brake light coming on when i would stop the vehicle. normally this means the float in the resovoir is below the full line but when checking the fluid level it is good. Am i fighting a leak or more air in the line? Any help would be appreciated.

 

[Anime]

If you haven't ever been losing fluid, it's not a leak. If you have to fill the reservoir every now and then, it could be a small leak that lets out some fluid, then sucks in air.

Assuming you don't have a leak, it's probably just air in the system. You're probably best off doing a full fluid change while you're at it, so just bleed each corner (starting with the passenger rear, then drivers rear, then passenger front, then driver front), and repeat until you get NO bubbles. Then bleed one last time. Be sure the bleeder screws are tight.

Keep in mind brake master cylinders do go, and when they go, you get a spongy pedal and eventually it goes to the floor. if bleeding does nothing, and you check both the front calipers/lines and rear cylinders/lines, and theres no leaks, I'd say replace the master.

 

[Four0Sport]

yeah.. master cylinder or booster is where my mind was going when it happened. I think i will try to fully bleed it. last time i bled the brakes i bled a full quart through.

 

[fixxxer]

I'm thinking time for a master cylinder rebuild or wheel cylinder rebuild kit. Last time I did a complete flush of my brakes, I used about a quart too.

 

[Four0Sport]

the last time I had my pass side rear drum off i noticed a little wetness around the boots of the wheel cylinder.. when the dr side cylinder failed the pedal went to the floor and the parking brake light came on. In the back of my mind i know i should pull the drum and check that cylinder but I really hate taking apart drum brake setups!

 

[fixxxer]

That does bite but that's also the most likely culprit.

 

[nitro71]

Buy the brake tools at harbor freight. The hook tool makes life so much better. They are easy with the right tools. Just lay the parks out exactly as you take them off. Or mark with some kinda marking stuff..

 

[Four0Sport]

its 90 outside right now.. so its gonna have to wait for a cooler day lol

 

[konstan]

I've been fighting a spongey pedal all spring/summer.

The rear drum brakes have parts in them that sometimes rust, springs that disintegrate, and a wire cable that may have gotten ground up or rusted through.

When that happens, applying brakes does not put the tension on the brake shoes. The wheel cylinder pistons expand outward without meeting any resistance from the shoes, so the brake pedal feels weak.

Bottom line, if this truck has not had rear brakes done (in the last, say, few years), it's time. Do the wheel cylinders too if you do the brakes. They are like $4 at RockAuto.

You will be very happy with the difference it makes.

 

[Four0Sport]

brake shoes have been replaced twice in the past 4 yrs. first time for wear, second time bc of a busted wheel cylinder. i need to change this one out too so that it doesnt ruin the shoes. man.