Difference between power and manual brake pedals?

[timinator]

I installed a Stainless Steel disc brake conversion kit on my 69 Charger. It will absolutely not work and is only getting 500 psi to the calipers. It was orginally a manual drum car and they worked fine. I have replaced several master cylinders with different sizes, added a power brake booster, replaced the distribution block and hard lines. Every component has been replaced and nothing changes the pressure reading at the caliper and the car will absolutely not stop. The tech line now says there is probably a difference between the manual vs power brake pedals and I have the wrong one installed. Is there a difference? I know the pushrod on the manual setup goes right to the master cylinder while the power one goes through a linkage assembly. I looked in the parts catalog and both types have the same part number. The tech claims there is a difference in pedals and I have the wrong one. He said the pushrod location is different where it attaches. I'm totally frustrated at this point and after spending over $1500, I'm going to have to go back to the original setup. At least that worked. So, my question is is there a difference in the pedals?

[Rolling_Thunder]

the pedals are the same as far as i know - the linkage is the only difference.

[Just 6T9 CHGR]

There is no difference in the pedal assys between manual & power.

I am running the SSBC kit as well.  At first I used the manual set up.  It did require a lot more foot pressure than the drums did to get the car to stop but it did stop well.  Took a little getting used to & when the pads were burnished to the rotors the effort was decreased a bit.  Took about 300 miles of driving
I have since converted to power which made the effort much less.  Still work great!

[werner]

dONT KNOW ABOUT PEDALS THEMSELVS BUT i DO KNOW THE STANDARD BRAKE PEDAL  SITS MCUCH HIGHER OFF THE FLOOR THAN WITH POWER BRAKES. STANADRAD BRAKE CAR THE CLUTCH PEDAL AND BRAKE PEDAL ARE LEVEL WITH EACH OTHER, POWER BRAKE CAR, THE CLUTCH PEDAL SITS MUCH HIGHER THAN THE BRAKE PEDAL

[Musicman]

Power Brakes typically use a pedal ratio of 4:1 to 5:1... Manual brakes use a pedal ratio of 6:1 or greater, giving you greater leverage and applying more pressure.

So much for that theory... You should have at least 1000 psi in the lines to the calipers. 500 psi works OK for drums, but it won't work for disc's.

SSBC 

[DJF]

I have the same problem exactly!!! SSBC all round. Car wont stop at all. I can be doin 5mph cant get it to jolt to a halt at all, its scarey. Im seeing 25" of vaume at times the booster is all good, I put enough pressure on the pedal I feel my knee cap will at any moment pop off and smack me in the chops and still the will not stop. This has been goin on for ages clearly the calipers are not getting the pressure they need to operate. My car is a 70 B-Body OE drum powered car. The stock booster is what SSBC recomends. Monday I had enough and I have ordered a Hyratech Hydro-Boost system Ouch!!! These things are expensive. I cant help but think there is somthing a miss between the booster size and/or the bore size of the MC on the SSBC kit. This hydroboost I hope is a cure. Still not what you need when you spend that sort of money, the kit sould work out the box right?

[Musicman]

Ah yes... yet another satisfied SSBC customer

[DJF]

When this Hydro kit arrives I will post to let you all know what difference it makes. Just wanted this car to be easier to live with in modern times. I Feel the frustration, worst part is there are so many of us with the same problem. Are we all missing somthing obvious?

[charger2fast4u]

i keep reading all these posts about SSBC brake kits only getting little caliper pressure. from what i seen some got lucky with using a different bore size master cylinder and solved the problem. and some had no luck with anything. i have the full SSBC brake kit for my 68 charger haven't put it on yet car is still at body shop. for paying over 2,000 for this kit i expect everything to work out of the box. but i know ill run into problems seeing everyone else did with this kit. i would think the problem would lay in the booster, master cylinder since these are what makes the pressure in the system. i think you just need to find the right combo

DJF do you got a link to this hydro kit ill be watching for your post to see if this solves the problem

[maxwellwedge]

I don't get how a drum M/C is goung to work with discs. A factory disc M/C front brake reservoir is way larger than the rear. Try using a M/C for discs.

[firefighter3931]

The small bore master cylinder is the key to making it work. You need a disc brake MC with a 7/8 or 15/16 bore....the SSBC master is 1 1/8. I spoke with Dr Diff about this very subject awhile back and his opinion was basicly to go with a small bore master to increase pressure on the 4 piston calipers. Mine is a 4 wheel power drum to manual disc conversion but i haven't driven the car yet. I'm not anticipating any problems but i'll know soon enough. 
 
Like Chris mentioned above it takes a bit of time to burn in the pads but after some thrashing it will get better.




Ron

[Long Island RT]

I have a Wilwood setup but have not run the car yet either.  I bought it from Dean @ Hot Rods USA.  He' very knowledgeable and has a great article on brakes explaining the math behind the conversions.  Here's a link to the page on his website with the explanation.

http://www.hotrodheaven.com/tech/brakes/brakes4_index.htm

He recommended a 7/8" mastercylinder with my full drum (power) to disc (manual) conversion.  It seems similiar to firefighter Ron's.  I hope it works.

[DJF]

i keep reading all these posts about SSBC brake kits only getting little caliper pressure. from what i seen some got lucky with using a different bore size master cylinder and solved the problem. and some had no luck with anything. i have the full SSBC brake kit for my 68 charger haven't put it on yet car is still at body shop. for paying over 2,000 for this kit i expect everything to work out of the box. but i know ill run into problems seeing everyone else did with this kit. i would think the problem would lay in the booster, master cylinder since these are what makes the pressure in the system. i think you just need to find the right combo

DJF do you got a link to this hydro kit ill be watching for your post to see if this solves the problem

Sure heres the manufacturers website.

http://www.hydratechbraking.com/

Doesnt give much info on the actual part there. But I ordered one from here :-


http://musclerodzstore.com/index.asp?PageAction=VIEWPROD&ProdID=41

[High Impact]

Well here's what I've learned~

            I installed the Scare Bird set up on my 69 bee which had manual drums and coverted it to power disk..............and used the same pedal but had to get the correct "swival thing" that bolted to the top of the brake pedal to hook up the booster....................BUT,  as someone said earlier in this post,   the brake pedal arms ARE DIFFRENT,  the manual one come's more straight down and the power one has a slight bend towards the driver.   

           As it stands for me right now,  with using the original maunal brake pedal I've got my pedal burried into the carpet on a sudden stop  but during normal driving it's "ok"...............just not safe (another one of those little projects


SO,  I think....... .......there is a diffrence.