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Brake pedal soft on first push...then firms up on second push?

Posted By Big6ft6 13 Years Ago
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Brake pedal soft on first push...then firms up on second push?

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55vickey
Posted 13 Years Ago
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Supercharged

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Way to go Nate, good video. I'm going to be in Mad Town on the 16th, you gonna be around?? Gary

       

Gary, 55 Vicky, St. Germain, Wisconsin

 

Grizzly
Posted 13 Years Ago
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Nate,

Good one mate Wink

Now for something more complcated w00t

Cheers

Warren

http://forums.y-blocksforever.com/Uploads/Images/41f30774-424d-428d-9c7a-e351.jpg Grizzly (Aussie Mainline)

Eddie Paskey
Posted 13 Years Ago
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Hey Nate;    GREAT   ---  Thanks for the thanks!!!!   God Bless    Eddie

Eddie

Lake Forest, Ca. 92630

MoonShadow
Posted 13 Years Ago
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Great. Glad to be of help. Chuck

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire
Big6ft6
Posted 13 Years Ago
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Moonshadow, you helped me solve the puzzle!  I went back and tighted the adjuster nuts as much as possible and tried the brakes, they were ROCK SOLID, couldn't even move the pedal.  So I knew the master cylinder was o.k. and no air in the lines.  I went around and loosened each wheel just enough to get about a half-rotation when I spin the wheel and I had a great pedal that firmed up about 75% of the way through the pedal travel.  I know you'res supposed to loosen them to the point of having a full roration of free spin, but I wanted to go out and do a couple hard stops just to make sure everthing was broken in.  Now I will back them off a little more next time I'm at the house.

I was just being too sensitive when I was adjusting the brakes, in the past I was tightenening the adjuster just until the brakes started to grab...then I backed 'em off a little.  Well things must not have been lined up inside the brake drums becuase this method was not getting me close enough.  But moonshadows advice to tighten 'em all the way first revealed my problem!

Since I have very little knowledge on Y-blcoks to share with you guys, I made you guys a thank you video instead.

http://youtu.be/fpcWFL4Lksk

Nate - Madison, Wisconsin
 
56 Ford Customline Sedan
 

MoonShadow
Posted 13 Years Ago
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One of the hardest things to troubleshoot is a defective new part. If I recall you did bench bleed the master cylinder. Did it hold firm then? Did you check to make sure the stroke was long enough on the pedal? You should only have a inch to inch and a half freeplay in the pedal before it starts to activate the master cylinder. Too much play and it wont get enough on one stroke to work.

All things said You probably need to try another MC to make sure yours is working. The internal leak by in the pump assembly will do what you are experiencing. Chuck

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

Big6ft6
Posted 13 Years Ago
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Moonshadow, no I did not tighten the adjuster all the way first.  It makes sense that would "center" the pads within the drum.  I will do that next.  If that doesn't reveal poorly adjusted front brakes.  My next step is going to be as Rick suggests and try another master cylinder.  What is strange is that once the pedal is firm on the second pump, it holds well...it doesn't fade.  The firmness doesn't appear until 1/2 way through the stroke of the second pump of the pedal.

Man...I always get a sick feeling when my troublshooting gets to the bottom of the bucket and I start considering my new (re-furb) part may be faulty.  That possibility is always in the back of your mind when you have a mystery problem, but the few times I've followed through and replaced a brand new part, it didn't solve the problem.  Nine out of ten times it is something really obvious.  But this one has me stumped for now, maybe this will become my personal experience with a faulty new part.

Nate - Madison, Wisconsin
 
56 Ford Customline Sedan
 

rick55
Posted 13 Years Ago
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I have experienced the problems you mention in the past. Bleed the brakes, get all the air out, drive the car out on the street, spongy pedal. My fix was to fit a new master cylinder, bleed it first on the bench, fit it and bleed the wheel cylinders in the order you have been told already. Problem solved.

I was told that master cylinders can bypass fluid internally and cause this problem. Sounded like BS to me but the problem was fixed after I put a new master cylinder on. I figured the internal cups were leaking. With twin reservoir MC if the front cup is faulty you'll never get it to function correctly. That is why they are fitted with switches.

I would try another MC and see if that fixes the problem.

Regards


Rick - West Australia
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MoonShadow
Posted 13 Years Ago
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Did you tighten the adjusters until you couldn't turn the wheels either way then back them off? That sets the brakes to the drum. Also how much freeplay, downward movement, it there in the pedal before it gets hard? Chuck

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire
Big6ft6
Posted 13 Years Ago
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Moonshadow.  I've already double checked the assembly, but I'll check again the assembly.  If I back off the adjuster nut, I can turn the wheel freely in both directions.  However as I expand the adjuster nut all of a sudden at a certain point, the wheel just locks in the forward direction.  I can turn it backwards easily still, but forwards it is like it is like it has a one-way ratched, and the shoes are grabbing and self-energizing with just the effort of my hand turning the tire.

Driving in the driveway this wasn't noticeable, it wasn't like the front wheels were dragging or anything.  In fact, other than having to pump the pedal twice the brakes really work well.  The car stops abruptly as soon as I get the pressure on the second pump of the pedal.

I'm using an adjustable rod I had laying around, I adjusted it so that it is just contacting the master cylinder pistone when the brake pedal is in the completely retracted position.   The MC came with a push rod, but it was like 4 inches too long for the brake pedal set up in the car.

Nate - Madison, Wisconsin
 
56 Ford Customline Sedan
 



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