brake Problem, spongy pedal

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Sep 18, 2012 | 11:43 AM

john59923

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brake Problem, spongy pedal

First post, here goes:

Ok, 84 f150 4wd, I finally replaced the broken rear springs that i have been sitting on for a year and decided to check the brake adjustment as I'm going start hauling weight(instead of just the garbage). I had replaced the Master cylinder last year and bled everything normally(push the pedal) and had great pedal feel and thought the back was just out of adjustment. After adjusting, i test drove it and found the back wasn't even working. So I tried to bleed them. no fluid. had a blocked port in the reman MC. New MC, Bleed everything again, New fluid all the way around. Now no front brakes, and pedal will not come up(yes, I did bench bleed the MC). WTH? I checked the proportioning valve and it's getting fluid through all ports. Now, even with a bad PV, I should get hard pedal, or could it be trapped air that isn't getting out when it's bled? BTW, I also gravity bled. Any suggestions?

Sep 18, 2012 | 11:55 AM

Franklin2

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From: Virginia

Gravity bleeding will give you a good start, but most of the time it will not get all the air completely out. Get someone to push the pedal down and hold it while you open the bleeders(you know how this goes correct?). And I have found out it will take more than the master cylinder will hold, to bleed the rear brakes completely, so stop halfway through and re-fill the reservoir for the back brakes(the smaller chamber).

Sep 18, 2012 | 12:13 PM

00Boss

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From: copperas cove tx

Also how are your rubber lines? As these age they will expand under pressure givin you a soft pedal even if you bleed eveythin right

Sep 18, 2012 | 12:56 PM

john59923

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Just checked the lines for bulging and that's not a problem. Also, did a pedal bleed again and still no fronts. brake light is still on(the dash) so i'm starting to guess there is still air in the PV that isn't coming out when bled. I'll try that and wash my hands before I touch my computer again(oops)!!

Sep 18, 2012 | 04:20 PM

john59923

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Well, apparently there was air in the PV. I bled it and then bled the brake again. Pedal came back. I must remember that with a blocked port, the brakes are going to have a nice tight pedal. With older cars and trucks won't be as "tight" as you'd think(although this depends on the vehicle). I was basing my thoughts on the tight feel, even though it was never like that before the MC was changed to begin with.

Anyway, I just had to have the patience to figure it out. I posted here out of my inability to think at the time. Sometimes that's all it takes for you to remember something is putting it writing and going back over what you've already done.

Thanks for your input!!!!

Sep 18, 2012 | 07:27 PM

joshofalltrades

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Quote:

Originally Posted by john59923

had a blocked port in the reman MC. New MC, Bleed everything again, New fluid all the way around. Now no front brakes, and pedal will not come up(yes, I did bench bleed the MC).

let me guess, reman by CARDONE - guaranteed failure every time