GM drum to disc swap - 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 06-06-2006, 07:56 PM
Registered User
 
Join Date: May 2004
Location: central florida
Age: 51
Posts: 9
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
GM drum to disc swap

Swapped from drum to disc on the rear of my race car. Limited to stock parts, and used the calipers from the front of a Caprice wagon '85 model. Used manual master cylinder, with no proportionary valve. Problem: no pedal without pumping several times. Minimal pedal with numerous pumps. Not enough to stop car. Need stock combination to allow me to utilize the rotors I have. They are after-market .81 thick, purchased from Speedway Motors and are the only part I can use that is after-market. ANY and ALL assistance appreciated.........thanks.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 06-06-2006, 11:44 PM
TooMany2count's Avatar
A Half Crippled Old SOB....
 
Last wiki edit: GM RPO build codes Last photo:
Join Date: Jan 2003
Location: Cahokia,IL..... Donate Blood Products & Sign your DONORS CARD
Posts: 807
Wiki Edits: 5

Thanks: 0
Thanked 1 Time in 1 Post
get a proportionary valve for 4 wheel disc brakes it should matter if they were power or not because the valve cant tell if u have power brakes or not. but then i would most likely run a power booster also if it was me.......joe
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 06-07-2006, 01:16 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
What master are you using?

Starting in about 83 GM started to change the angles cut in the calipers for the square cut o-ring. This allowed the pistons to retract more from the rotor yielding more MPG because of less drag. However to do this they needed to use a step bore master cylinder. They had a large (40mm mostly) piston that would move lots of fluid and would transition to the smaller bore (1.125" in the case of the caprice) to keep peddle effort down. As you found out mixing the 2 up doesn't work too well. I also bet that you have way too much braking in the rear. Best bet would be new MC with a larger bore and smaller calipers in the rear (like metric calipers)
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 06-07-2006, 03:44 PM
Registered User
 
Join Date: May 2004
Location: central florida
Age: 51
Posts: 9
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
If I obtained some calipers from the front of a 79 Camaro or 'bird, and used a single cell master cylinder (50's style), would I solve my problem? Trying to solve the problem before sat. nite.........gotta big race comin up........
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 06-07-2006, 05:21 PM
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
I don't know if it is in the rules but a residual pressure valve should help part of your problem. The 50's MC would just make things worse. If the peddle effort isn't too high you might try a larger (power brake) MC...but your rear calipers will still be too big.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 07-30-2012, 08:40 AM
Registered User
 
Join Date: Jul 2012
Posts: 15
Wiki Edits: 0

Thanks: 3
Thanked 0 Times in 0 Posts
I am building a v8 s10 and been having issues stopping my tires at a stand still and i switched from stock drums to a 2004 stock blazer 3.73 dis1c and it solved about 70% of my problem. if that helps. didnt have to change anything bolted right up
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:
If you do not want to register, fill this field only and the name will be used as user name for your post.
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
GM 3.1 FWD swap question. Hippie Engine 2 05-22-2006 10:26 PM
69 ford drum to disc brakes bigdav Suspension - Brakes - Steering 1 02-04-2006 09:15 PM
rear drum to disc conv. nd500 Suspension - Brakes - Steering 8 06-20-2003 10:18 PM
8.5 GM 10 BOLT CARRIER SWAP, POSSIBLE?? PURPLEOMEGA Transmission - Rearend 0 09-18-2002 03:04 AM
Drum to Disc????? riffs3 Suspension - Brakes - Steering 3 07-22-2002 06:26 PM


All times are GMT -6. The time now is 10:27 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.