Firewall pic request..power brake and manual brake car

[carcrazyguy]

Anyone have a firewall picture of a 71 B-body firewall area? Looking for a picture that shows the mounting area for the master cylinder on a manual brake car (without the master cylinder on) and a picture of the same area on a power brake car (without the power booster on).

Trying to see what the difference is in those areas so that I can locate the parts that I need.

 

[rocky61201]

Here is a firewall pic of a 4 wheel drum manual brake car.

 

[carcrazyguy]

Okay, now it will be trying to figure out if 71's had a different firewall plate for manual or power brakes. If so then I can see what the mounting plate should look like so I can hunt for one.

Here is the plate on my car.....

 

[rocky61201]

You also need to think about the pedal ratio for manual and power brake. They should be different. Your pedal ratio is important for either power or manual brake systems. With a power brake system if your pedal ratio is too high you will have sensitive brakes and if it’s too low your braking will be poor. With a manual brake system the same will apply although too high a pedal ratio is rarely a problem. As a general rule of thumb your pedal ratio should not exceed:
6:1 for manual brakes with a 1” bore master cylinder
4:1 for power brakes with a 1 1/8” bore master cylinder

Pedal ratio is calculated by the distance from the top to the bottom of your brake pedal divided by the distance from the top of your brake pedal to the hole/pickup point of your master cylinder. You can google brake pedal ratio to find a diagram.

I'm converting to power brakes and I know this is probably gonna be an issue when I get the car back on the road. I may swith back to a small bore manual master cylinder to solve it.

 

[carcrazyguy]

To make sure I have not screwed up to much already, a little background. The car was a 4 wheel manual drum brake car. This is a list of what we have purchased so far...
Front - Wilwood Dynalite Pro Series(Part #140-11020-D)
Rear - Wilwood Dynalite Pro Series (Part #140-11395-D) with parking brake
Master cylinder - Wilwood 1 1/8" Bore dual outlet aluminum tandem chamber (Part #260-8556)
Booster - shows factory 71 Charger DISC/drum replacement http://www.oreillyauto.com/site/c/de...+brake+booster
Proportioning valve - Wilwood adjustable (part#260-8419)


So are you saying that I need to find a pedal assembly and the entire bracket assembly from a power brake car? Or is the 1 1/8" master cylinder correcting the ratio issue?:thinker:

 

[moparmarks]

You need the power brake backing plate and this bell crank. That will mount the booster you have and connect to your pedal.

- - - Updated - - -

Here is how it mounts.

 

[moparmarks]

The pedal assy is the same. You will need to drive out those 2 studs. Here are the backing plates.
I have the power plate and bell crank if you need.
I e-mailed you about the headliner trim too.

 

[carcrazyguy]

Moparmarks, I will take the brake hardware. Just email me or pm me and let me know!

I am pretty sure the headliner trim has been taken care of. My dad found some locally where the car is being reassembled. I am waiting to hear back if they were the correct parts that the shop needed. I know for sure I need the brake hardware, so let me know and I will PayPal you,again. I will need them shipped to my dads place so he can run out to the shop that is working on the car!

 

[rocky61201]

Moparmark's - those are the pics I've been wanting to see for probably two years! Thanks.