hard pedal

[dont vote]

   i have a 69 w/all drums, i recently rebuilt the engine with a 501 lift cam. i've read that this cam robs the engine of vacuum, i have installed a new vacuum booster and also a vacuum can from summit in addition to the factory one under the battery tray, the only results i got was the headlights opened just slightly faster. the pedal is still hard and will not stop the car, any suggestions and help would be greatly appreciated.

[A383Wing]

Either you don't have vacuum to the booster, or the booster is bad

[mikepmcs]

Also, could the rod be out of adjustment or not adjusted correctly.  I remember Chris G(6t9)saying something about this I think.

[Ghoste]

Glazed drums or shoes?

[mikepmcs]

Ghoste...I believe he is talking about the pedal actually being hard as a rock when you push down on it, like no travel and pushing a brick wall.  I've experienced what he is talking about and it isn't like glazed drums or shoes IMHO.

[Ghoste]

Oh I see.  I was reading it as no matter how hard he pushes it's like well, you know .
My bad.

[mikepmcs]

He might mean that too.  We'll have to await the response I guess.

[dont vote]

yes exactly, no travel and pushing a brick wall. how did you fix the problem? like i said before, new brake booster and vacuum can,
still the same. it was good before the rebuild, i seem to need more vacuum

[A383Wing]

With engine running, do you have vacuum to the booster? You will have to remove the check valve from the booster to check...

[dont vote]

i didn't check for vac to the booster, i will check that tomorrow. i just assumed i had some as everything was new. i'll get back to you on that

[dont vote]

And assuming i have no vac to the booster, how can i get some?

[A383Wing]

From the nipple on the intake manifold.

[dont vote]

 well, right now the hose goes from the nipple, to the new can, and from the can to the brake booster

[A383Wing]

well, right now the hose goes from the nipple, to the new can, and from the can to the brake booster

Wonder if you got the hoses reversed on the new can...that might have a check valve in it...again, see if you have vacuum at the booster with engine running...then we go from there

[dont vote]

i have vaccum everywhere but the brake pedal is still hard how much do i need?

[oldcarnut]

Also, could the rod be out of adjustment or not adjusted correctly.  I remember Chris G(6t9)saying something about this I think.

Did you check the rod position from the booster to the master cyl?  Could the under dash linkages be binding? One more thing a little off the wall but have you had to add much or refill the master cyl.?  What happened to me with similar hard pedal but on an old booster was that the seals were bad causing the booster to fill with brake fluid.   
Check this link out http://www.dodgecharger.com/forum/index.php/topic,54379.0.html

[dont vote]

the rod seems to be at the correct length
there is no fluid loss and also no binding in the linkage the pedal does have a little freeplay.
the pedal has about 1 and 1 half inch travel, very firm all the way and needs two feet to actually stop the car from rolling at idle, also the pedal feels the same whether the car is running or not.  my brother uses this cam in his 350 chevy w/o a vac can and has 5 times the vacuum at the booster than i have

[dont vote]

HELP i still have the problem

[mikepmcs]

Bad booster?
edit, just read your first post about new booster.

[mikepmcs]

i didn't check for vac to the booster, i will check that tomorrow. i just assumed i had some as everything was new. i'll get back to you on that

this part/test was completed? 

[dont vote]

yes, how do i test the new booster.manifold vac is at approx at 5 inches/hg at idle and at 4000 rpm climbs to 20.
i could hook the kirby up to the booster

[maxwellwedge]

Did you bench bleed the master? An improperly bled master can cause a hard pedal.

[mikepmcs]

Did you bench bleed the master? An improperly bled master can cause a hard pedal.

Shoot, beat me to it.

Amazing what that will cause if not bled properly.  You wouldn't think so but....

[A383Wing]

If master was not bench bled, it would give him a "soft" pedal...sounds to me like it's a "lack of enough vacuum" issue at the booster...he says he has only 5" of vacuum at idle....engine will barely run with 5" of vacuum at idle...I'm thinking he has a check valve, bad hose, restricted hose or a bad vacuum can that he added.

He needs to measure vacuum at every connection he has to find the problem. Start at the intake port and then test every connection next in line...bleeding the master cylinder will not cure the issue

[maxwellwedge]

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.