Disc Brakes Locking Up - 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 07-14-2013, 01:40 PM
Member
 
Join Date: Jul 2002
Location: MS
Posts: 44
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Disc Brakes Locking Up

Got a 37 Ford with 4 wheel discs and metric GM calipers. About 6 months ago, my front brakes started locking up. I replaced the MC because I figured that was the obvious answer because there was rust in the front brake reservoir. Surprisingly, that didn't fix it. I removed the residual valve, inspected it, and it looked fine. I finally just bought another one after having nothing else to blame it on. The brakes worked better than ever before, and life was great. I shut her down over the winter and spring. The other day, I got in it, and the brakes felt really firm. Almost too firm. After a few pumps of the pedal, I started to feel resistance on the car. It got a little worse at every stop. By just 5 miles, they were almost locked up. After about 15 minutes just sitting in a parking lot, they started to loosen up. I managed to get home without touching the brake.

I checked the pedal, and nothing was binding. The MC fluid looks clean. All four corners are locking and I just don't know what the deal is. I am using a Corvette style MC and 2# residual valves. Any suggestions?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 07-14-2013, 02:29 PM
sedanbob's Avatar
Registered User
 
Last photo:
Join Date: Oct 2008
Location: St. Louis
Age: 65
Posts: 626
Wiki Edits: 0

Thanks: 61
Thanked 80 Times in 77 Posts
Are your brakes manual, or do you have a booster? If you have a booster, did you check the clearance on the pushrod - if there isn't sufficient clearance, the booster could be applying the brakes without you touching the pedal.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 07-14-2013, 07:34 PM
Member
 
Join Date: Jul 2002
Location: MS
Posts: 44
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I have power brakes with a booster. I will check that out. Thanks.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 07-16-2013, 06:30 AM
Member
 
Join Date: Jul 2002
Location: MS
Posts: 44
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I checked it out yesterday, and the booster pushrod is pushing in the MC about 1/8". The car was cold, and I hadn't touched the pedal, if that makes any difference.

What's proper way to have it set up. Does the pushrod need to be barely touching the MC? Does there need to be a little slack?
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 07-16-2013, 11:22 AM
sedanbob's Avatar
Registered User
 
Last photo:
Join Date: Oct 2008
Location: St. Louis
Age: 65
Posts: 626
Wiki Edits: 0

Thanks: 61
Thanked 80 Times in 77 Posts
There needs to be a small gap. The procedure for measuring is in this attachment, pages 52-53 - they recommend .1 to .5 mm (small, but necessary).
Here's the attachment: http://www.autoshop101.com/forms/brake05.pdf

Hope this helps.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 07-16-2013, 01:09 PM
1971BB427's Avatar
Registered User
 

Last journal entry: Latest changes
Last photo:
Join Date: Dec 2010
Location: Portland
Posts: 1,580
Wiki Edits: 0

Thanks: 14
Thanked 249 Times in 216 Posts
I had a similar problem with drum brakes on my present project. Couldn't get them to release, and couldn't even get them bled properly. Had all sorts of trouble, and eventually decided to pull the master.
While pulling the master I noticed pressure from the brake operating rod, so I tried to adjust some free play into the rod. Since I'd swapped from a single master to a dual, it seems the operating rod was too long. I ended up having to cut things and rework it to get free pedal play, but once I did it all worked perfect.
This is a drum-drum system, with no booster, so it doesn't have to be power brakes to have the same problem.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 07-16-2013, 01:23 PM
ajtorsiello's Avatar
Registered User
 
Join Date: May 2013
Posts: 6
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Had the same problem on my 34 ford. I also had to shorten the rod on the booster. Seemed cold it was OK but after it got hot it would bind up.

Alan
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 07-16-2013, 03:05 PM
Member
 
Join Date: Jul 2002
Location: MS
Posts: 44
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Thanks bob. It's always exciting when you find a solution to frustrating problem.

When mine worked okay, it was in the late fall. I'm not sure if it's coincidence or that temp plays a part.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 07-16-2013, 05:40 PM
sedanbob's Avatar
Registered User
 
Last photo:
Join Date: Oct 2008
Location: St. Louis
Age: 65
Posts: 626
Wiki Edits: 0

Thanks: 61
Thanked 80 Times in 77 Posts
I hope that fixes it for you. Let us know either way.
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
brakes locking up and stumped scottsdale kid Suspension - Brakes - Steering 12 06-16-2012 10:09 PM
rear brakes locking up tcoop Suspension - Brakes - Steering 11 05-22-2010 03:09 PM
front disc locking up loctite Suspension - Brakes - Steering 11 04-03-2009 06:58 AM
Brakes gradually locking up fastrehotrods Suspension - Brakes - Steering 13 12-16-2006 01:22 AM
Locking drum brakes burninrubbah617 Suspension - Brakes - Steering 1 01-15-2006 02:09 PM


All times are GMT -6. The time now is 07:49 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.