Come to the masters of making things work - 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> Hotrodding Basics
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 01-12-2013, 04:05 PM
Registered User
 
Last photo:
Join Date: Oct 2012
Posts: 101
Wiki Edits: 0

Thanks: 2
Thanked 0 Times in 0 Posts
Come to the masters of making things work

Lets just say that a guy needed more fluid volume to his rear drum brakes or maybe all of the drum brakes on all 4 wheels but there was no larger bore master cylinder avail than the one he had now, what could he do?

Ok heres the deal, I have 4 rear wheel cylinders on my rear axle, I have installed the largest diam bore master cylinder I could find that will fit on my power brake booster ( 1 1/4 inch ) still cannot get a brake pedal. There is a possibility that my master just cannot push enough fluid to fill all 6 wheel cylinders.

What can I do to increase the volume/pressure?

I have been looking at different ideas and believe there is a solution but what might that be?

I understand there is products such as hydroassist ect but these rely on the engine to be running ect, I need to figure out first how to get a pedal whilst the truck is just sitting in a no run situation

    Advertisement

Last edited by Oilyrascal; 01-12-2013 at 04:14 PM.
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 01-12-2013, 04:23 PM
Member
 
Join Date: Aug 2003
Location: California
Posts: 903
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Oilyrascal,

I am guessing that you have bled the air out of the lines. But on rear brake cylinders some times you need to raise the back of the car WAY up and use a power bleeder. Once all of the air is out make sure the brake shoes are adjusted properly. Adding a larger diameter master cylinder is not going to help your problem. I am figuring there is air in the lines. Otherwise you would have pedal.

Did you by chance bleed the front brakes? They could be causing the problem.

Scholman
Reply With Quote Quick reply to this message
The Following User Says Thank You to scholman For This Useful Post:
V305 (01-14-2013)
  #3 (permalink)  
Old 01-12-2013, 04:27 PM
Registered User
 
Last photo:
Join Date: Oct 2012
Posts: 101
Wiki Edits: 0

Thanks: 2
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by scholman View Post
Oilyrascal,

I am guessing that you have bled the air out of the lines. But on rear brake cylinders some times you need to raise the back of the car WAY up and use a power bleeder. Once all of the air is out make sure the brake shoes are adjusted properly. Adding a larger diameter master cylinder is not going to help your problem. I am figuring there is air in the lines. Otherwise you would have pedal.

Did you by chance bleed the front brakes? They could be causing the problem.

Scholman
It would be a task to raise the rear up waay up on this truck but I could lower the front down to the ground, I think I have heard of this and may just give it a try, thanks
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 01-12-2013, 04:45 PM
1971BB427's Avatar
Registered User
 

Last journal entry: Latest changes
Last photo:
Join Date: Dec 2010
Location: Portland
Posts: 2,073
Wiki Edits: 0

Thanks: 20
Thanked 372 Times in 329 Posts
Make sure there's no air in the system, but also make sure you've got proper shoe adjustment too. If the shoes aren't adjusted up properly, then no amount of fluid will be enough to make them contact the drum. They need to be close enough to barely drag, and then when you hit the pedal they wont travel far to full contact.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 01-12-2013, 04:52 PM
Registered User
 
Last photo:
Join Date: Oct 2012
Posts: 101
Wiki Edits: 0

Thanks: 2
Thanked 0 Times in 0 Posts
Thanks, yes I have all this covered, I assumed there was a way to increase my fluid volume, something I could add too my system, maybe I was wrong
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 01-12-2013, 04:58 PM
MARTINSR's Avatar
Brian Martin,Freelance adviser
 
Last photo:
Join Date: Jun 2004
Location: San francisco bay area
Age: 56
Posts: 13,432
Wiki Edits: 0

Thanks: 1,567
Thanked 1,320 Times in 1,146 Posts
What bore master went with the four wheel cylinders originally? What did these wheel cylinders come out of, I assume you didn't make up this system creating the four wheel cylinders where there once was two, what did it come from?

A smaller cyl is needed to provide more fluid pressure, maybe you have went to big? The thing is once the system is full of fluid, hardly any needs to actually "move". So I don't see how adding another wheel cylinder would change anything anyway.

Brian
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 01-12-2013, 05:13 PM
Registered User
 
Last photo:
Join Date: Oct 2012
Posts: 101
Wiki Edits: 0

Thanks: 2
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by MARTINSR View Post
What bore master went with the four wheel cylinders originally? What did these wheel cylinders come out of, I assume you didn't make up this system creating the four wheel cylinders where there once was two, what did it come from?

A smaller cyl is needed to provide more fluid pressure, maybe you have went to big? The thing is once the system is full of fluid, hardly any needs to actually "move". So I don't see how adding another wheel cylinder would change anything anyway.

Brian
Its 6 wheel cylinders total, 4 in the rear two in the front, 1.5 original bore with some sort of hydrovac booster mounted under the cab. 1952 F-7 Ford truck

This is something that is definitely part of the equation .....maybe you have went to big?
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 01-12-2013, 05:18 PM
MARTINSR's Avatar
Brian Martin,Freelance adviser
 
Last photo:
Join Date: Jun 2004
Location: San francisco bay area
Age: 56
Posts: 13,432
Wiki Edits: 0

Thanks: 1,567
Thanked 1,320 Times in 1,146 Posts
That is what I am asking, what was the bore of the original master? When the truck sold they did stop right?


Brian
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 01-12-2013, 05:21 PM
Registered User
 
Last photo:
Join Date: Oct 2012
Posts: 101
Wiki Edits: 0

Thanks: 2
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by MARTINSR View Post
That is what I am asking, what was the bore of the original master? When the truck sold they did stop right?


Brian
1.5 original bore with some sort of hydrovac booster mounted under the cab
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 01-12-2013, 05:48 PM
MARTINSR's Avatar
Brian Martin,Freelance adviser
 
Last photo:
Join Date: Jun 2004
Location: San francisco bay area
Age: 56
Posts: 13,432
Wiki Edits: 0

Thanks: 1,567
Thanked 1,320 Times in 1,146 Posts
Well if it originally had a 1.5 and it stopped you don't need a bigger one, there is some other problem like it isn't bled properly or shoes aren't adjusted properly or something. You aren't running a power brake booster at all now? If that is the case you may need to change your leverage on the brake pedal. I know that on sixties cars that I have worked on switching them from power to manual requires moving the rod that pushes the piston in the master cylinder nearer the pivot point on the brake pedal so you have more leverage. Maybe this is the problem? It makes a BIG difference on the amount of leverage you have.

Brian
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 01-12-2013, 05:56 PM
Member
 
Join Date: Aug 2003
Location: California
Posts: 903
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Oilyrascal,

I have worked on this type truck and they can be a pain in the neck.
You have air in the system. Use a pressure tank at the master cylinder and start bleeding the system from the right rear then the left rear then the front right and lastly the front left.
Your hydrovac could be letting air into the system too. check the bleed valve on it also.
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 01-12-2013, 07:13 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 60
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 598 Times in 547 Posts
You can have a slight drag and still not be fully adjusted. I take the brake shoes out until they're tight in the drum then back them off to a ever-so-light drag.
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 01-12-2013, 07:43 PM
Registered User
 
Last photo:
Join Date: Oct 2012
Posts: 101
Wiki Edits: 0

Thanks: 2
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by MARTINSR View Post
Well if it originally had a 1.5 and it stopped you don't need a bigger one, there is some other problem like it isn't bled properly or shoes aren't adjusted properly or something. You aren't running a power brake booster at all now? If that is the case you may need to change your leverage on the brake pedal. I know that on sixties cars that I have worked on switching them from power to manual requires moving the rod that pushes the piston in the master cylinder nearer the pivot point on the brake pedal so you have more leverage. Maybe this is the problem? It makes a BIG difference on the amount of leverage you have.

Brian
I am sorry, maybe my math is not so good or how I typed my letters, original it had a 1 1/2 bore, the biggest master I have been able to find thus far that woul dmount onto my power brake booster is 1 1/4 inch, a difference of 1/4 inch.

I hope this is clearer

Moving the pivot point closer, that is something I will have to remember and look into further so I am clearer on what you mean. Thanks
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 01-12-2013, 07:46 PM
Registered User
 
Last photo:
Join Date: Oct 2012
Posts: 101
Wiki Edits: 0

Thanks: 2
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by scholman View Post
Oilyrascal,

I have worked on this type truck and they can be a pain in the neck.
You have air in the system. Use a pressure tank at the master cylinder and start bleeding the system from the right rear then the left rear then the front right and lastly the front left.
Your hydrovac could be letting air into the system too. check the bleed valve on it also.
I have no hydrovac, that is what was original for the truck, I have mounted a late model master and power brake booster onto the firewall, also put pedals up under the dash to move all of this.

So you have bled them? What do you mean by use a pressure tank at the master, can you show me what you mean with a picture, explain to me better the procedure?
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 01-12-2013, 07:48 PM
Registered User
 
Last photo:
Join Date: Oct 2012
Posts: 101
Wiki Edits: 0

Thanks: 2
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by cobalt327 View Post
You can have a slight drag and still not be fully adjusted. I take the brake shoes out until they're tight in the drum then back them off to a ever-so-light drag.
Thats pretty much where they are at now, I mounted a new master today, I went thru 2 of the Napa Cordone masters, I did not like how they bench bled. I now have one I got at autozone, I did like how it benchbled.

I need to get some more info maybe on best way to bleed them, I have been told to raise the rear end, I like this idea, makes sense, also pressurize the master, I like this also, will wait to hear more on how to do this. Thanks again
Reply With Quote Quick reply to this message

Recent Hotrodding Basics posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




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

Posting Rules
You may post new threads
You may 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
Making wheels at work...... Thought I'd share zbhover Hotrodders' Lounge 5 11-20-2011 08:35 PM
The little things you wind up making.... Centerline Hotrodders' Lounge 10 10-17-2010 09:13 AM
Making Things Right... onovakind67 Off-Topic 2 11-07-2006 02:06 PM
Funny things heard at work. schnitz Off-Topic 33 11-08-2005 08:17 PM
Making Progress or making more work for myself?! Weimer Hotrodders' Lounge 5 02-15-2004 04:11 PM


All times are GMT -6. The time now is 03:11 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.