Soft Brakes... - 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 08-08-2009, 04:55 PM
S10xGN's Avatar
Gotta love a turbo!
 

Last journal entry: Body on Frame today.
Last photo:
Join Date: Aug 2004
Location: Port Neches, TX
Age: 61
Posts: 1,641
Wiki Edits: 0

Thanks: 0
Thanked 58 Times in 55 Posts
Soft Brakes...

Hi All,

I finally got to make my "maiden voyage" in my '72 Maverick project, encountering a few minor problems. My main concern is the brakes (manual disc/drum setup). The pedal is firm, but goes to the floor. I bench-bled the M/C initally when I started the system using silicone fluid. After fixing the leaks, I switched over to DOT #4 fluid. I drained as much silicone as possible, I then flushed the system with methanol, then added the DOT #4 and bled everything until I got the DOT #4 at all wheel cylinders.

Would pressure bleeding help? Is that something I can do at the house? What's the max pressure I should put on the M/C?

TIA!

Russ

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 08-08-2009, 06:02 PM
T-bucket23's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Engine basic condition - how to check Last photo:
Join Date: Aug 2005
Location: Massachusetts
Age: 56
Posts: 5,084
Wiki Edits: 26

Thanks: 7
Thanked 100 Times in 86 Posts
Explain firm but goes to the floor, that is contradictory.
__________________
Artificial Intelligence is no match for Natural Stupidity



Chet
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 08-08-2009, 06:03 PM
carsavvycook's Avatar
My 2 cents worth
 
Last photo:
Join Date: Sep 2007
Location: Lakeside, CA
Age: 57
Posts: 2,855
Wiki Edits: 3

Thanks: 2
Thanked 2 Times in 2 Posts
I am thinking you have done some damage to the rubber seals, and brake hoses. These were designed to use DOT3 brake fluid only.

The only other thought I have, is, there is still some air in the system to be bled out.

The only way to tell if the rubber has been effected, is to take the master cylinder apart, and look at the rubber seals for swelling. I would start here, then check the rest of the system.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 08-08-2009, 06:17 PM
S10xGN's Avatar
Gotta love a turbo!
 

Last journal entry: Body on Frame today.
Last photo:
Join Date: Aug 2004
Location: Port Neches, TX
Age: 61
Posts: 1,641
Wiki Edits: 0

Thanks: 0
Thanked 58 Times in 55 Posts
I should have posed this as a question: Will a pressure bleeder adequately bleed the M/C as well as the rest of the system?

Russ

Quote:
Originally Posted by T-bucket23
Explain firm but goes to the floor, that is contradictory.
Sorry, it's a manual brake system, thus the pedal is firm. It stops, but goes to the floor. If it was "boosted", it prolly wouldn't be firm?

Quote:
Originally Posted by T-carsavvycook
I am thinking you have done some damage to the rubber seals, and brake hoses. These were designed to use DOT3 brake fluid only.

The only other thought I have, is, there is still some air in the system to be bled out.

The only way to tell if the rubber has been effected, is to take the master cylinder apart, and look at the rubber seals for swelling. I would start here, then check the rest of the system.
The silicone fluid was in there just long enough to check for leaks, maybe a week total. Would this (really?) be an issue?
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 08-08-2009, 07:31 PM
carsavvycook's Avatar
My 2 cents worth
 
Last photo:
Join Date: Sep 2007
Location: Lakeside, CA
Age: 57
Posts: 2,855
Wiki Edits: 3

Thanks: 2
Thanked 2 Times in 2 Posts
"The silicone fluid was in there just long enough to check for leaks, maybe a week total. Would this (really?) be an issue?"

I have seen it several times, that I remember, over the years. I always ask what brake fluid was added, when a vehicle get's towed in for brakes, with no pedal, and the master cylinder reservoir is full.

I have found swelled, and 'soft' seals, or shrunk, and 'split' seals.

I have never done a comparison test, and all I have is DOT4 fluid here right now, with no wheel cylinder cups.

Dot4 fluid should be fine, when used with DOT3 parts. It is the Silicone fluid, I have seen used, that will attack the rubber that is not made for silicone fluid usage. How long it takes, I do not know.

The use of Methanol to flush a brake system, I have never heard of. How it would effect the rubber would be very interesting to find out.

I will try to acquire some seal-able glass jars, and some Silicone Brake fluid, and some Methanol, and some wheel cylinder cups early next week. I will then post the results of my findings.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 08-08-2009, 09:09 PM
ericnova72's Avatar
More for Less Racer
 
Join Date: Jan 2007
Location: S.W. Lower Michigan
Age: 47
Posts: 8,899
Wiki Edits: 0

Thanks: 19
Thanked 362 Times in 332 Posts
I think the Methanol was the problem, just like it is in fuel hoses that aren't compatible with alchohol fuels. This has especially come to light with the recent push of E-85 fuel. All the fuel hoses, seals, needle and seat tips etc have to be compatible with alchohol or they will swell.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 08-08-2009, 09:14 PM
carsavvycook's Avatar
My 2 cents worth
 
Last photo:
Join Date: Sep 2007
Location: Lakeside, CA
Age: 57
Posts: 2,855
Wiki Edits: 3

Thanks: 2
Thanked 2 Times in 2 Posts
Quote:
Originally Posted by ericnova72
I think the Methanol was the problem, just like it is in fuel hoses that aren't compatible with alchohol fuels. This has especially come to light with the recent push of E-85 fuel. All the fuel hoses, seals, needle and seat tips etc have to be compatible with alchohol or they will swell.
I agree! My tests should prove it.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 08-09-2009, 08:36 AM
S10xGN's Avatar
Gotta love a turbo!
 

Last journal entry: Body on Frame today.
Last photo:
Join Date: Aug 2004
Location: Port Neches, TX
Age: 61
Posts: 1,641
Wiki Edits: 0

Thanks: 0
Thanked 58 Times in 55 Posts
Quote:
Originally Posted by ericnova72
I think the Methanol was the problem, just like it is in fuel hoses that aren't compatible with alchohol fuels. This has especially come to light with the recent push of E-85 fuel. All the fuel hoses, seals, needle and seat tips etc have to be compatible with alchohol or they will swell.
Might be the case *if* the meth was in there longer than the length of time it took to flow clear, maybe 10 minutes. I just can't see it guys, sorry... Eric, I appreciate your time in testing, hope it's not the issue (at least in my timeframe).

Russ
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 08-16-2009, 09:11 AM
S10xGN's Avatar
Gotta love a turbo!
 

Last journal entry: Body on Frame today.
Last photo:
Join Date: Aug 2004
Location: Port Neches, TX
Age: 61
Posts: 1,641
Wiki Edits: 0

Thanks: 0
Thanked 58 Times in 55 Posts
Fixed!

I'm pretty sure most of the pedal problem was due to the rear brakes not being fully adjusted. Originally I had run the car (on jackstands) at idle in reverse and tapped the brakes a few times. This time, I ran it up to 2500 in reverse and slammed the brakes about 20 times. I also built a pressure bleeding adaptor for my M/C, put 30# air pressure on it, and rebled the brakes but that didn't really change anything...

Russ
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 08-16-2009, 07:00 PM
scrot's Avatar
Registered User
 
Last photo:
Join Date: Apr 2006
Location: In front computer
Posts: 449
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Methanol .
Where did you get that from?
Do you mean methanol racing fuel in the brake system?

Quote:
I will try to acquire some seal-able glass jars, and some Silicone Brake fluid, and some Methanol, and some wheel cylinder cups early next week. I will then post the results of my findings
carsavvycook, I'll be looking forward to that test.
I love that kind of **** (tests).
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 08-16-2009, 07:59 PM
carsavvycook's Avatar
My 2 cents worth
 
Last photo:
Join Date: Sep 2007
Location: Lakeside, CA
Age: 57
Posts: 2,855
Wiki Edits: 3

Thanks: 2
Thanked 2 Times in 2 Posts
Quote:
Originally Posted by scrot
Methanol .
Where did you get that from?
Do you mean methanol racing fuel in the brake system?



carsavvycook, I'll be looking forward to that test.
I love that kind of **** (tests).
I have not been able to find any sources to get any yet.

I really wish I could. I want to know the effect it has on the rubber parts in brake systems.

The only source I have now, is nitro methane.
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 08-17-2009, 09:05 PM
Registered User
 
Last photo:
Join Date: Jan 2009
Location: Springfield, MO
Age: 29
Posts: 1,100
Wiki Edits: 0

Thanks: 5
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by carsavvycook
I have not been able to find any sources to get any yet.

I really wish I could. I want to know the effect it has on the rubber parts in brake systems.

The only source I have now, is nitro methane.
Methanol is used for BioDiesel production. I am in the process of getting the stuff around to make biodiesel. I have been told on many ocassions that the YELLOW bottles of "HEET" gas line antifreeze are methanol and can thus be used for small "test batches" of biodiesel. So maybe a yellow bottle of heet will work for your test?
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 08-23-2009, 11:36 AM
GrumpyOldMan0_0's Avatar
Registered User
 
Last photo:
Join Date: Jul 2009
Location: Saugerties,New York
Age: 58
Posts: 9
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Silicone-based brake fluids are regarded as DOT 5 brake fluids. They are highly compressible and can give the driver a feeling of a spongy pedal. The higher the brake system temperature the more the compressibility of the fluid and this increases the feeling of a spongy pedal.
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 08-24-2009, 01:06 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
Silicone fluid by itself it not noticeably compressable, but it does aerate and all the little bubbles are compressable.

Using silicone fluid in a brake system then running dot 4 afterwards usually will swell the seals, but I have heard that flushing with denatured alcohol usually will keep the seals from swelling...Methanol is alcohol. I never chanced it myself, being as I have had too many cars in my shop that needed every rubber part replaced after a switch from dot 5 to dot 3 or 4. I never did a study on how long it took for the silicone to permeate the seals enough that a switch down to dot4 would swell them up.

A quick test is to take a new cup seal and push it against a suspect seal...the seals should compress equally..if one seal is noticably softer than the other..it's trash.

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

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
Need Help With My Brakes S10 Racer Suspension - Brakes - Steering 4 01-18-2009 02:00 PM
79 malibu soft brakes mikes68493 Suspension - Brakes - Steering 5 06-12-2007 08:37 PM
Hotrodders Knowledge Base: Suspension - Brakes - Steering Jon Suspension - Brakes - Steering 0 11-26-2005 06:29 PM
G body with manual brakes - it works! - pics dh79 Suspension - Brakes - Steering 7 08-27-2005 10:55 PM
Brakes locking up in non ABS system nprfan Suspension - Brakes - Steering 9 08-24-2005 12:37 PM


All times are GMT -6. The time now is 08:34 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.