Brake Pedal ratio: manual-to-power conversion - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Suspension - Brakes - Steering
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 06-21-2007, 06:08 AM
Registered User
 
Join Date: Nov 2005
Location: Cedar Rapids, IA
Age: 55
Posts: 8
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Brake Pedal ratio: manual-to-power conversion

Shopping for a manual-drum-to-power-disc brake conversion for my '64 Mercury Monterey, I stumbled across a tech article at mpbrakes.com talking about pedal ratio (basically the amount of leverage your pedal is capable of exerting on the master cylinder).

http://www.mpbrakes.com/uploads/docu...alratiopdf.pdf

My factory-stock manual drum set-up has a pedal ratio of 6:1 (12" long pedal, 2" from pedal bushing to push rod).

Looks to me like Mercury used the same brake pedal and pedal bracket regardless of manual or power brake systems. I've checked the Lincoln-Mercury parts manual, and I've studied the shop manual... there is not a different pedal setup or part for power brakes. (What I haven't done is find an old Merc or Ford with power brakes and compare - I don't have a parts car!)

Here's my question: is pedal ratio a big deal or not? if this is important, then my options are (help me out here!) - stick with a manual disc conversion, or find a different pedal / pedal bracket setup to reduce my pedal ratio down near 4:1.

HELP!!!!!

Thanks
Walt
Reply With Quote
  #2 (permalink)  
Old 06-21-2007, 08:11 AM
powerrodsmike's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Make a fiberglass fan shroud
Last journal entry: Next.. ..Bagging the king B (barge)
Last photo:
Join Date: Jan 2005
Location: gilroy, california
Age: 52
Posts: 4,107
Wiki Edits: 161

Thanks: 0
Thanked 1 Time in 1 Post
Many times Ford used the same pedal. As a general rule, 6:1 is on the outside edge of the range of pedal ratios for power brakes, but you could go up a size on your master cylinder to make it feel better.

Depending on the size of your calipers, if you set up your new power brake system with a 11" booster and 1" bore master and bleed it properly and you still have a low soft pedal, put an 1 1/16 or 1 1/8" bore master cylinder . If you are using a 7" or a 9" booster you probably can use the 1" and be ok.

Some of the manufacturers of retrofit power brake kits will supply an angled booster bracket that enables you to drill a new pushrod hole lower on the pedal, so you can get the ratio closer to 5:1 (drill your pushrod hole 1/2" lower), or if you really want to be at 4:1 drill it 1" lower.

As your Mercury is a somewhat rare car to be converted to power brakes, be ready to do some fine tuning on the system if you use aftermarket conversions.

Masterpower is a good company, but you still have to mess with their products sometimes.

I have started dealing with a company called Brake Tech Solutions, Anwar, (the owner), is very knowlegeable and helpful. I have found that if he could not help me with a weird application, he will give me the name of a source that may be able to help.

That's a true hotrodder

Later, mikey
__________________
my signature lines...not really directed at anyone in particular..

BE different....ACT normal.

No one is completely useless..They can always be used as a bad example
Reply With Quote
  #3 (permalink)  
Old 06-21-2007, 06:12 PM
Registered User
 
Join Date: Nov 2005
Location: Cedar Rapids, IA
Age: 55
Posts: 8
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Anwar at BTS

Quote:
Originally Posted by powerrodsmike
I have started dealing with a company called Brake Tech Solutions, Anwar, (the owner), is very knowlegeable and helpful. I have found that if he could not help me with a weird application, he will give me the name of a source that may be able to help.

Later, mikey
I've heard good things about BTS from a local custom builder. I shot a quick email to Anwar and he's been very helpful. I plan to give him a call tomorrow to finish chasing down some final details about his conversion kit. I'll let you know how the conversion goes.
Reply With Quote

Recent Suspension - Brakes - Steering posts with photos


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Disc Brake Conversion On 1937 Plymouth jjp Suspension - Brakes - Steering 1 01-30-2007 01:17 PM
power brake conversion frankgv Suspension - Brakes - Steering 1 01-10-2007 06:48 PM
power brake conversion frankgv Engine 0 01-09-2007 01:57 PM
No pedal pressure after power brake install oldschoolrods Suspension - Brakes - Steering 3 05-18-2005 07:19 AM
possible hard pedal blackbeard Suspension - Brakes - Steering 16 01-10-2005 06:23 AM


All times are GMT -6. The time now is 01:48 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2013, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.