Master Cylinder Bore Size W/Hydroboost? - 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 02-28-2007, 10:07 AM
Registered User
 
Last photo:
Join Date: Dec 2005
Location: Dallas Oregon
Posts: 60
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Master Cylinder Bore Size W/Hydroboost?

I am planning to change the power brakes on my Ranchero to a Hydroboost system. The Hydroboost unit I have is from a 1-ton diesel pickup, and has a 1-5/16" bore master cylinder. The ranchero's present M/C has a 1" bore. With all things being equal, I know that increasing bore size will increase pedal effort/lower pressure in the lines. Thhis leads to the question: Does the added boost of the hydro offset the bore size issue? An unknown is the pedal linkage ratio of the donor vehicle (86 K30). Options I have are to stay with the 1-5/16" cylinder or find a 1" one that will fit the HB.

Thoughts, anyone?

thanks,

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 02-28-2007, 11:46 AM
xntrik's Avatar
Save a horse, Ride a Cowboy.
 
Last photo:
Join Date: Jul 2005
Location: Arkansas
Posts: 5,131
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
I had a new 77 Ford Country Squire 460 trailer package that had hydroboost on it. You might check that MC.

I also saw an 80 Mercury Monarch (Granada) with front discs only that had hydroboost. I have been kicking myself ever since for not getting the HB from it before it hit the crusher. It had an 8.7 rear that I put into a Versailles that I got the 9" disc rear out of. The front discs went onto a 65 Falcon.

Last edited by xntrik; 02-28-2007 at 11:51 AM.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 02-28-2007, 12:41 PM
66GMC's Avatar
Get in, sit down, hang on
 

Last journal entry: Cab Removal
Last photo:
Join Date: May 2005
Location: Olds, Alberta Canada
Age: 57
Posts: 2,761
Wiki Edits: 0

Thanks: 32
Thanked 90 Times in 85 Posts
Quote:
Originally Posted by krehmkej
I am planning to change the power brakes on my Ranchero to a Hydroboost system. The Hydroboost unit I have is from a 1-ton diesel pickup, and has a 1-5/16" bore master cylinder. The ranchero's present M/C has a 1" bore. With all things being equal, I know that increasing bore size will increase pedal effort/lower pressure in the lines. Thhis leads to the question: Does the added boost of the hydro offset the bore size issue? An unknown is the pedal linkage ratio of the donor vehicle (86 K30). Options I have are to stay with the 1-5/16" cylinder or find a 1" one that will fit the HB.

Thoughts, anyone?

thanks,
There's a good chance that I'm assuming wrong here, but I thought that almost all master cylinders mount up universally. (2-bolt mount)

The original single system MC on my 66 GMC was the same mounting as the split-sytem (dual) MC from the 79 GMC.

Have you tried bolting the Ranchero M/C up to the GM H/B?
Did the Ranchero have power (vacuum) brakes previously?

I guess what I'm getting at is that you may already have the correct master cylinder, and possibly the factory Ranchero brake pedal and rod may also work with the HB. Most of the brake parts are mfr'd by the same vendor (ie Bendix, Wagner)

As far as I know ... the method of providing pedal effort assistance (hydroboost or vacuum) is the only difference ... and you're just substituting one for the other.


73(?) Ranchero (You didn't say what year)


One of two (Stamped "1605") that fit an 86 K30


The other one (Stamped "1925")

The mounting on all 3 looks the same to me ...
What do the rest of you guys think ... am I nuts?

Last edited by 66GMC; 02-28-2007 at 12:50 PM.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 02-28-2007, 02:01 PM
Registered User
 
Last photo:
Join Date: Dec 2005
Location: Dallas Oregon
Posts: 60
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Ford and Chevy a marriage made in Hell

First thought was just mounting the Ranchero (78) MC to the Hydroboost. Discovered that the Chevy uses a 3.4" center to center measurement, whereas the Ford is 3.2" That would mean "hogging" out the mounting holes, or rotating the HB 90 degrees and making an adaptor AND a new pushrod. So, trying to keep it simple, just figured to get a smaller diameter Chevy MC if bore is truly an issue.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 02-28-2007, 06:44 PM
66GMC's Avatar
Get in, sit down, hang on
 

Last journal entry: Cab Removal
Last photo:
Join Date: May 2005
Location: Olds, Alberta Canada
Age: 57
Posts: 2,761
Wiki Edits: 0

Thanks: 32
Thanked 90 Times in 85 Posts
Quote:
Originally Posted by krehmkej
First thought was just mounting the Ranchero (78) MC to the Hydroboost. Discovered that the Chevy uses a 3.4" center to center measurement, whereas the Ford is 3.2" That would mean "hogging" out the mounting holes, or rotating the HB 90 degrees and making an adaptor AND a new pushrod. So, trying to keep it simple, just figured to get a smaller diameter Chevy MC if bore is truly an issue.
3.4" vs 3.2" ... bummer.

In addition to the bore sizes, you will also probably want to find an MC with the same sized fittings ON THE SAME SIDE, otherwise you are looking at adapter fittings and/or re-plumbing. <sheesh>


I would expect the GM hydrobosster to have Metric O-ring fittings on the hoses as well, whereas your Ranchero probably uses inverted flare fittings, right?

It mighty be easier to find or order a "Ford" hydrobooster or a custom-fit kit?

These guys make custom hydroboost kits. Be sure to check out the movies in the Multimedia section.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 03-03-2007, 01:19 AM
Member
 
Last wiki edit: Vacuum brake bleeder set up
Join Date: Nov 2003
Location: So Cal
Posts: 1,245
Wiki Edits: 8

Thanks: 0
Thanked 0 Times in 0 Posts
Hydro-boost adds a lot of boost. What do you have to loose trying it? A few $5 adapters to hook it up to your brake lines? Hook it up and try it out. If there is too much pedal effort just buy a smaller GM master.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 03-03-2007, 08:00 AM
Registered User
 

Last journal entry: Bravada bucket seats
Last photo:
Join Date: Feb 2006
Location: minto, nd
Posts: 12
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Did you look to see if a master cylinder from a 5.7 diesel with hydroboost will work?

Rick
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 03-03-2007, 08:30 AM
Registered User
 
Last photo:
Join Date: Dec 2005
Location: Dallas Oregon
Posts: 60
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Good thought. Did not even know they had such a small diesel. 1/2 ton pickup? I was given the whole setup and would like to use as much as possible after a good cleaning.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 03-03-2007, 09:22 AM
Registered User
 
Last wiki edit: Wheelbase database Last photo:
Join Date: Jan 2007
Location: Virginia
Posts: 3,593
Wiki Edits: 1

Thanks: 6
Thanked 159 Times in 146 Posts
The 5.7 diesel is the ill-fated Oldsmobile diesel (die-sell). It was used in a wide variety of GM cars and trucks from the mid-1970s through at least 1982. All used a hydroboost brake booster.

Note that if you're mixing and matching master cylinders, you need to watch for the booster-to-MC pushrod length.
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 03-03-2007, 12:24 PM
Registered User
 
Last photo:
Join Date: Dec 2005
Location: Dallas Oregon
Posts: 60
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I hear you on the pushrod length issue. If the 1-ton MC doesn't work out I plan to just take it to NAPA and dig through their selection on Chevy ones.
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 03-03-2007, 03:24 PM
66GMC's Avatar
Get in, sit down, hang on
 

Last journal entry: Cab Removal
Last photo:
Join Date: May 2005
Location: Olds, Alberta Canada
Age: 57
Posts: 2,761
Wiki Edits: 0

Thanks: 32
Thanked 90 Times in 85 Posts
Quote:
Originally Posted by krehmkej
I hear you on the pushrod length issue. If the 1-ton MC doesn't work out I plan to just take it to NAPA and dig through their selection on Chevy ones.

Just so you know ... that booster-to-m/cyl rod (and associated hardware) is NOT included with either the remanufactured NAPA booster or master cylinder.

All of the parts in this picture were "harvested" from an auto-wecker unit, and used with the reman NAPA components.
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 03-04-2007, 09:58 AM
Registered User
 
Last photo:
Join Date: Dec 2005
Location: Dallas Oregon
Posts: 60
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Interesting picture. Thanks. I had thought that the brake pedal to HB rod was "staked" in. Obviously not the case. This unit came from a running truck. I had not planned to open it up - my manual says it cannot be worked on, replace as a unit. Obviously these pieces came out without difficulty. If possible, I would like to remove the brake pedal rod to shorten it rather than doing that with it in place.
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 03-04-2007, 10:27 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: 53
Posts: 4,108
Wiki Edits: 161

Thanks: 0
Thanked 3 Times in 3 Posts
I would think that the 1 5/16 MC is way too big for your Ranchero calipers. Check the piston size difference of the truck calipers to your car calipers and I'll bet there is a difference.
The brakes will be so touchy it will be painful to drive.

I would look at a 1 1/8 or a 1" bore that will fit the HB unit.

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 Quick reply to this message
  #14 (permalink)  
Old 03-04-2007, 11:22 AM
66GMC's Avatar
Get in, sit down, hang on
 

Last journal entry: Cab Removal
Last photo:
Join Date: May 2005
Location: Olds, Alberta Canada
Age: 57
Posts: 2,761
Wiki Edits: 0

Thanks: 32
Thanked 90 Times in 85 Posts
Quote:
Originally Posted by krehmkej
Interesting picture. Thanks. I had thought that the brake pedal to HB rod was "staked" in. Obviously not the case. This unit came from a running truck. I had not planned to open it up - my manual says it cannot be worked on, replace as a unit. Obviously these pieces came out without difficulty. If possible, I would like to remove the brake pedal rod to shorten it rather than doing that with it in place.
I think there was a locking clip that held the pushrod (Pedal to HB) that you can release by sliding a tubular object along the rod.

None of this stuff is internal to the HB unit ... they're right ... not user serviceable.

The star-shaped clip, spring, and intermediate rod are in between the HB and the MC.

The external snap-ring was behind the HB to firewall retaining nut, and is designed to make sure that the nut cannot possible vibrate loose and fall off.

The remaining items are a pre-bent return line, hose mounting bracket, and tube clip.
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 03-04-2007, 01:10 PM
Registered User
 
Last wiki edit: Wheelbase database Last photo:
Join Date: Jan 2007
Location: Virginia
Posts: 3,593
Wiki Edits: 1

Thanks: 6
Thanked 159 Times in 146 Posts
Quote:
Originally Posted by 66GMC
None of this stuff is internal to the HB unit ... they're right ... not user serviceable.
That's not true. My 86 Chevy truck service manual details how to rebuild a hydroboost. There are rebuild kits periodically offered on ebay for $40-50. A lot cheaper than the $250 for a rebuilt unit.

Note for the last 20 years or so, GM has broken its service manuals up and publishes a separate "Unit Repair Manual". That's where the info on rebuilding the brake boosters, steering boxes, transmissions, and axles is located.
Reply With Quote Quick reply to this message

Recent Suspension - Brakes - Steering 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
Master Cylinder Failure? Houston54 Suspension - Brakes - Steering 2 10-24-2005 02:22 PM
39 Deluxe master cylinder adapter? MM in NM Suspension - Brakes - Steering 4 09-30-2005 03:42 PM
Bore size question 53LEDSLED Engine 5 05-12-2005 06:55 PM
1966 Chev PU upgrade to dual master cylinder for existing brakes Bannear Suspension - Brakes - Steering 7 10-23-2002 01:15 PM
Stang master cylinder Old Crow Suspension - Brakes - Steering 3 06-10-2002 12:40 PM


All times are GMT -6. The time now is 02:25 AM.


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.