Bleeding brakes-pedal pressure problem. Could use some advice/suggestions

[glennpm]

Originally Posted by acchaplin

Another one of those videos said that the smaller MC bore, the more pressure, the bigger the MC bore the more volume. Didn't know that. They used a math formula to figure of which MC bore to the pedal ratio to use. All that math 'siphern is way above my 6 remaining "brain cells." I can do fractions in my head, but that is it.

I'd like to take a look at that video. Please post the link.

Regarding volumes and pressures:

The parameters are somewhat fixed:

- Brake lever ration which is 3.85 for you
- Leg force to apply brakes. Of course this is variable but figure on 100 LBS force.

The above two fixed variables will give you a brake line pressure that depends on the internal diameter of the MC.

Pressure = Force/Area psi
Area = Pi X (Diameter/2)**2
F = 100lbs X 3.85 (pedal arm ratio)

P = (100 Lbs) X 3.85 / (1.00/2)** X 3.1416 = 490psi

So ... , the way to get higher pressure is to increase the pedal arm ratio or decrease the internal diameter of the MC, or more leg force :-)

A larger diameter MC will push more brake fluid volume at the cost of decreasing the brake line psi with a smaller stroke of the brake pedal.
A smaller MC diameter will give you more pressure but also more stroke which is not the greatest for modified '32s.

I use a stepped bore MC, https://www.fordbarn.com/forum/showt...nder&showall=1

Glenn

[acchaplin]

Originally Posted by glennpm

I'd like to take a look at that video. Please post the link.

Regarding volumes and pressures:

The parameters are somewhat fixed:

- Brake lever ration which is 3.85 for you
- Leg force to apply brakes. Of course this is variable but figure on 100 LBS force.

The above two fixed variables will give you a brake line pressure that depends on the internal diameter of the MC.

Pressure = Force/Area psi
Area = Pi X (Diameter/2)**2
F = 100lbs X 3.85 (pedal arm ratio)

P = (100 Lbs) X 3.85 / (1.00/2)** X 3.1416 = 490psi

So ... , the way to get higher pressure is to increase the pedal arm ratio or decrease the internal diameter of the MC, or more leg force :-)

A larger diameter MC will push more brake fluid volume at the cost of decreasing the brake line psi with a smaller stroke of the brake pedal.
A smaller MC diameter will give you more pressure but also more stroke which is not the greatest for modified '32s.

I use a stepped bore MC, https://www.fordbarn.com/forum/showt...nder&showall=1

Glenn

Oh feces! My 'brane' just exploded and went into 'lockdown'! Now my eyes are locked in crossed. I get VERY confused when trying to read math forumlas. Anything past gradeshool level (except for fractions) adding, dividing, I can't comprehend.

If I have to now understand math, gemotery forumlas to get brakes to work on this car. I'll just quit now (save on the migrane pain) and try to trade the '32 for a nice running/driving '50 Chevy Convt.

THANKS for your help Glenn!

[acchaplin]

[QUOTE=glennpm;2346090]I'd like to take a look at that video. Please post the link.

She used the TV remote to put those brake videos on the TV. The computer was not involved.