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Thread: Spongy brakes get better after pumping the brakes hard 1 time

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    Spongy brakes get better after pumping the brakes hard 1 time

    So like the title says, the pedal is squishy till I pump the pedal hard 1 tone, then it feels alright till I restart the truck, then back to squishy again.

    I have good rotors and pads, only 6 or 7 months old, and I flushed all brand new fluid at the same time.

    I've searched a few different forums and keep seeing the adjuster rod trick, but I'm not seeing any one with a complaint like mine before doing the mod.

    Any ideas?

    Sold my 2002 BLK #9638 to my wife's uncle, Sold my 2003 BLK #6682 to a nameless man local to me.

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    Sounds like air in the line or and caliper leaking out.

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    Could be an issue with the brake booster. The vacuum boosters get hard when you push them with the engine off. When the motor is running creating stored vacuum it is softer. If there is an issue with the booster, I say scrap it and go hydroboost! I did one in my truck and it's a night and day difference. More then likely it's a hose going to the booster

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    Quote Originally Posted by SR81 View Post
    Sounds like air in the line or and caliper leaking out.
    I am 99% positive there is 0 air in the line, as I bled through all fresh fluid and never let the MC get low enough to suck air. I have checked all 4 calipers and they are all clean and not leaking that I can see.

    Quote Originally Posted by tpr103 View Post
    Could be an issue with the brake booster. The vacuum boosters get hard when you push them with the engine off. When the motor is running creating stored vacuum it is softer. If there is an issue with the booster, I say scrap it and go hydroboost! I did one in my truck and it's a night and day difference. More then likely it's a hose going to the booster
    I think you're right that it is a vacuum issue in the booster or the line from the intake to the booster. Cause 1 hard push on the pedal with the truck running and it is fine till I turn it off. I don't know if I can replace just the line, or if I can even source it. I replaced my uncles vac booster on his '97 F150 cause his was leaking, you could hear it driving down the road hissing air.

    I plan to do a hydroboost conversion eventually, just can't afford it right now...the time or the dollars lol. Just looking to make it a little better till I can do the conversion.

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    Quote Originally Posted by SoCal Waite View Post
    I am 99% positive there is 0 air in the line, as I bled through all fresh fluid and never let the MC get low enough to suck air. I have checked all 4 calipers and they are all clean and not leaking that I can see.



    I think you're right that it is a vacuum issue in the booster or the line from the intake to the booster. Cause 1 hard push on the pedal with the truck running and it is fine till I turn it off. I don't know if I can replace just the line, or if I can even source it. I replaced my uncles vac booster on his '97 F150 cause his was leaking, you could hear it driving down the road hissing air.

    I plan to do a hydroboost conversion eventually, just can't afford it right now...the time or the dollars lol. Just looking to make it a little better till I can do the conversion.
    Damn wish I didn't throw my old vacuum booster in the trash. I woulda sent it to you. I did buy a complete hydro boot out of a wrecked f250 complete with all the lines for $45 2 weeks ago. I'm planning on installing them on my gas f250 soon.

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    Quote Originally Posted by tpr103 View Post
    Damn wish I didn't throw my old vacuum booster in the trash. I woulda sent it to you. I did buy a complete hydro boot out of a wrecked f250 complete with all the lines for $45 2 weeks ago. I'm planning on installing them on my gas f250 soon.
    Damn! $45?? thats what a new vacuum boost can is at the parts store...maybe I can afford it

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    Well that's what I paid for it. Guy wanted $100

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    How old are your rubber brake lines? These can lead to a spongy brake pedal feel. Maybe upgrade to the stainless flex lines. Those will give you a firmer brake feel.

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    Quote Originally Posted by RazzBarlow7 View Post
    How old are your rubber brake lines? These can lead to a spongy brake pedal feel. Maybe upgrade to the stainless flex lines. Those will give you a firmer brake feel.
    As far as I know they are OEM with only 80k on them. Though I do agree that SS lines will help the overall feel of the brakes, I am certain rubber lines are not the cause of my issue here. As Rich pointed out, this is presenting itself as a vacuum issue.

    When it is time to upgrade to the Hydroboost, I will also convert to the SS lines, as the line pressure could potentially be a lot higher in an emergency situation.

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