hard pedal

[A383Wing]

Un-bled lines will give a soft pedal. An improperly bled Power Brake master can give a hard pedal - the same feeling of trying to stop a power brake car with the engine off. It sounds like he has enough vacuum to pull a golf ball through a garden hose. 

I disagree....he states he has 5" at idle..you call that enough? I don't

I also disagree with you about the master bleed also...if there is air in the master, it will give you a soft pedal...not a hard pedal

[dont vote]

it's 5 @ the manifold nipple

[dont vote]

did i mention it's a 318 punched to a 323?

[A383Wing]

it's 5 @ the manifold nipple

Well, there's yer first problem...not enough vacuum to operate booster. Got a big cam? How does the engine run? Where do you have the booster hose attached to? Got a picture? You say it idles...what is idle RPM?

We need a little better info in order to help ya...pictures would be a plus also

[dont vote]

there should be enough info in the threads, it idles at 1100 and it runs really good
the hose runs from the nipple in the manifold to the check valve on the new can then from the can to the booster.
i may have to use an electric vacuum pump, if i know it will help, i just dont know if it will

[oldcarnut]

Run a vacuum direct from the nipple to the booster and see what happens.  I know mine doesn't use a can but this is how it is on my 70 RR stock 383.  If it works for the brakes then maybe you may have a vacuum problem somewhere else in the system you can look at. 

[CornDogsCharger]

Very interesting topic.  I've run into the same problem with the 'Bird that I am restoring.  The only problem is... I am reading 12psi at the booster.  Original booster was "fixed" three times and still no luck.  We replaced with with a Wagner remanufactured Bendix unit and still no luck.  Petal is hard as a rock.  We crimped off every hose except the booster, no luck.  Check valve is good... booster holds good vacuum when the check valve is removed.  We even put 25psi vacuum on the booster and had no luck.  Please help.  The car is a '70 Superbird 440 6 pack stock rebuild with a a little over mild cam.  Like I said, when we put direct vacuum on the booster, seem like it should have works..... if it was a lack of vacuum problem.

Justin
"CornDog"

[maxwellwedge]

Have a look at my earlier suggestion that nobody believes.

[CornDogsCharger]

What is different about bench bleeding a power assist master cylinder oppose to bleeding a non-power assist master cylinder.  I'm willing to try anything.

Justin
"CornDog"

[mikepmcs]

IMHO there should be no difference as far as bench bleeding the master cylinder goes.  same process in other words.  you could take the m/c off the booster and run 2 lines from the outlets back into the res and pump it to get all the air out or you can unhook the car lines, run 2 lines from the outlet to the res and pump the crap out of the booster to push the plunger to get the air out.

[mikepmcs]

http://www.superchevy.com/technical/chassis/brakes/0509sc_bench/index.html

http://www.tegger.com/hondafaq/mastercylinderreplace/benchbleeding.html

http://www.vw-resource.com/bench_bleed.html


video in this one
http://www.denlorstools.com/home/dt1/page_7445/automotive_brake_bleeding_exclusive_tech_article.html

[maxwellwedge]

Have a look at my earlier suggestion that nobody believes.

Nobody except mikepmcs   

[mikepmcs]

 

[CornDogsCharger]

Ok, guess I read it wrong.  Maxwell, I was thinking that your post was saying that it was different opperation.  Proof positive that I have been working too much lately.  I didn't think it could have been much different.  I'm pretty sure everything was bled out like it is supposed to be but hey, I'll give it a shot. 

Justin
"CornDog"

[bearbqd]

Glad this topic came up as I have the same problem with my Charger. I figured I had a bad booster as I have vacuum at idle at the booster. I just stuck my finger to it and didn't actually measure it. I have a pretty lopey cam so there probably isn't as much there as I think. How much vacuum should I have there if I measure it?

[CornDogsCharger]

Glad this topic came up as I have the same problem with my Charger. I figured I had a bad booster as I have vacuum at idle at the booster. I just stuck my finger to it and didn't actually measure it. I have a pretty lopey cam so there probably isn't as much there as I think. How much vacuum should I have there if I measure it?

When we were testing ours, we were pulling 12psi which to my understanding, should be enough to opperate the brakes properly.

Justin
"CornDog"

[TylerCharger69]

I was reading the posts and thought to myself..."Isn't the can underneath the battery tray's purpose is to store vacuum for the headlight doors to operate when the engine is off???"  I hooked up the vacuum direct to the manifold and tossed the can seeing as how the diaphragm was dry rotted.  I just need to make sure I shut my lights down BEFORE shutting down the engine...lol  Actually...I had this problem too and it turned out to be my proportioning block. It had some sort of restriction in it. Got a new one and solved the issue.  Just my 

[OneFine69]

   Hey dont vote, i'm kinda new 2 the forum, but ur prob aint. i've been readin ur post, tryin 2 figgur out a way 2 help ya. yeah 5inches of vacuum @ idle is no way near enuf vacuum 4 the brakes 2 work, u need about 15-18 in/hg. tyler had a good point about the prop valve, if its blocked, the fluid can't move,causing a hard pedal. did u check that? if it's a stocker, then maybe somethin may have gotten in there & blocked up the system. i'm no brake xpert by any stretch, thats just my 2 pennies. get back 2 us & let us know if u have any luck!

[y3chargerrt]

Ummm Spell Check?

[mikepmcs]

too much text messaging on the cell phone will cause that condition.

Welcome aboard OneFine69.

[OneFine69]

   Thank You, Mike, & yeah i do alot of phone txtin, how could u tell? is it really that obvious? its just a little easier on the thumbs, less blisters ya know lol

[y3chargerrt]

Welcome aboard and just teasing with the spell check comment. My daughters 19 so I know all about U wuz iz.....

[TylerCharger69]

yeah...it just seems that there is a blockage somewhere to me.  Have somebody in the car pressing the pedal.  Start from the rear and work your way forward. Loosen each bleeder one at a time and see when the pedal finally gives.  If it doesn't give, then the trouble is obviously somewhere between the prop. valve and the master cylinder, which the piston in the master cylinder could be frozen up.  Rod adjustment may be off as well meaning it's adjusted too far out and when it's assembled, the piston may already be engaged.  Also  if that spacer at the m/c is missing (cast piece I believe) that will cause grief as well.  Let us know!!!    Ace

[dont vote]

ok i will try each wheel , i dont think its a prop valve on the 318's but i did change it when the motor was out, i got it from a 440 charger, maybe i'll put the old one back in as i had really shitty brakes before the rebuild (locking-up @ rear,that may have been the leaky axle seal) So i will bleed each corner and i'll get back to you
  thanks

[oldcarnut]

ok i will try each wheel , i had really shitty brakes before the rebuild (locking-up @ rear,So i will bleed each corner and i'll get back to you

Did you ever change the rubber flex lines when you changed the other parts?  I've had one burst on me on the front and another time the hose was collapsing or deteriorating to the point on the inside that it acted as a check valve allowing fluid one way but not the other on the rear.  They're cheap (about $8 or so) and often neglected since often they look ok on the outside.  Just something to look at while your under there.