Welcome to Club Hot Rod!  The premier site for everything to do with Hot Rod, Customs, Low Riders, Rat Rods, and more. 

  •  » Members from all over the US and the world!
  •  » Help from all over the world for your questions
  •  » Build logs for you and all members
  •  » Blogs
  •  » Image Gallery
  •  » Many thousands of members and hundreds of thousands of posts! 

YES! I want to register an account for free right now!  p.s.: For registered members this ad will NOT show

 
Like Tree13Likes
  • 1 Post By techinspector1
  • 1 Post By 40FordDeluxe
  • 1 Post By firebird77clone
  • 1 Post By rspears
  • 1 Post By glennsexton
  • 2 Post By firebird77clone
  • 1 Post By Dave Severson
  • 1 Post By techinspector1
  • 4 Post By Dave Severson

Thread: Brakes for the Impala
          
   
   

Reply To Thread
Results 1 to 12 of 12
  1. #1
    Dave Severson is offline CHR Member/Contributor Visit my Photo Gallery
    Join Date
    Jul 2003
    Location
    Madison
    Car Year, Make, Model: '67 Ranchero, '57 Chevy, '82 Camaro,
    Posts
    21,160

    Brakes for the Impala

     



    Ok, so most of the early cars with drum brakes all around ran a bigger brake line to the rear of the car, I always figured this was because the old wheel cylinders/drum brakes required more volume of fluid? Anyway, converting the '66 over to 4 wheel discs, there should be no reason to have the larger line to the rear, is there? Thinking it will be fine to have all the lines as 3/16" withe the brake hoses as -3 Stainless?
    Yesterday is history, tomorrow is a mystery, Live for Today!
    Carroll Shelby

    Learning must be difficult for those who already know it all!!!!

  2. #2
    techinspector1's Avatar
    techinspector1 is offline CHR Member Visit my Photo Gallery
    Join Date
    May 2003
    Location
    Zephyrhills, Florida, USA
    Car Year, Make, Model: '32 Henway
    Posts
    12,423

    I'm thinkin' that once all the lines are filled with fluid, the rears will not know that they are not on the front and vice versa. You run the same size left to right and that works ok, right?
    .
    Dave Severson likes this.
    PLANET EARTH, INSANE ASYLUM FOR THE UNIVERSE.

  3. #3
    Dave Severson is offline CHR Member/Contributor Visit my Photo Gallery
    Join Date
    Jul 2003
    Location
    Madison
    Car Year, Make, Model: '67 Ranchero, '57 Chevy, '82 Camaro,
    Posts
    21,160

    Quote Originally Posted by techinspector1 View Post
    I'm thinkin' that once all the lines are filled with fluid, the rears will not know that they are not on the front and vice versa. You run the same size left to right and that works ok, right?
    .
    That's what I thought too, just wanted to check and see if I was overlooking some reason for the larger line to the rear.....
    Yesterday is history, tomorrow is a mystery, Live for Today!
    Carroll Shelby

    Learning must be difficult for those who already know it all!!!!

  4. #4
    40FordDeluxe's Avatar
    40FordDeluxe is offline CHR Member Visit my Photo Gallery
    Join Date
    Apr 2011
    Location
    Prairie City
    Car Year, Make, Model: 40 Ford Deluxe, 68 Corvette, 72&76 K30
    Posts
    7,264
    Blog Entries
    1

    I always figured it was a flow situation too. On most pick ups they run a 1/4" line to the rear and at the flexible hose it goes to a T and into 3/16" most times. I think it would be fine leaving the larger line.

    .
    Dave Severson likes this.
    Ryan
    1940 Ford Deluxe Tudor 354 Hemi 46RH Electric Blue w/multi-color flames, Ford 9" Residing in multiple pieces
    1968 Corvette Coupe 5.9 Cummins Drag Car 11.43@130mph No stall leaving the line with 1250 rpm's and poor 2.2 60'
    1972 Chevy K30 Longhorn P-pumped 24v Compound Turbos 47RH Just another money pit
    1971 Camaro RS 5.3 BTR Stage 3 cam, SuperT10
    Tire Sizes

  5. #5
    firebird77clone's Avatar
    firebird77clone is offline CHR Member Visit my Photo Gallery
    Join Date
    Sep 2005
    Location
    Hamilton
    Car Year, Make, Model: 69 nomad, 73 charger, 74 vega
    Posts
    3,900

    Interesting question.

    I just did about 20 minutes of research and this is what I found:

    Hydraulic theory: brake fluid does compress but so little as to be insignificant.

    Tubing does expand when pressure is applied. The bigger the tubing, the more it will expand. Enough to be noticeable? Opinions vary.

    Bleeding: might be easier with smaller tubing.

    Volume: we're not flowing fuel. Brakes function with very little flow. If ya don't believe me, do the math. It's about pressure. Larger tubing will flow at lower resistance. Significant amount? Doubtful.

    The more I think on it, the more I expect the answer is going to be related to manufacturing costs, not performance.
    Dave Severson likes this.
    .
    Education is expensive. Keep that in mind, and you'll never be terribly upset when a project goes awry.
    EG

  6. #6
    rspears's Avatar
    rspears is online now CHR Member/Contributor Visit my Photo Gallery
    Join Date
    Sep 2007
    Location
    Gardner, KS
    Car Year, Make, Model: '33 HiBoy Coupe, '32 HiBoy Roadster
    Posts
    10,987

    I'm wondering if it was a formal calculation tied in with wanting to load the front brakes slightly ahead of the rears? Just seems to me that for a given pedal movement/pressure with 3/16" line to the fronts and 1/4" line to the rears, the pressure is going to increase just a tiny bit earlier in the fronts than the rears, just due to the volume difference, but then will equalize. I'm not sure of that, but it kind of makes sense to me.
    Dave Severson likes this.
    Roger
    Enjoy the little things in life, and you may look back one day and realize that they were really the BIG things.

  7. #7
    glennsexton's Avatar
    glennsexton is offline CHR Member/Contributor Visit my Photo Gallery
    Join Date
    Mar 2005
    Location
    Tigard
    Car Year, Make, Model: 63 Nova SS
    Posts
    2,572

    Aggressive driving (or using a lot of brake when towing) generates heat. Brake pads can reach extremely high temperatures (OEM brake pads operate best in the 100°F to 650°F range while racing and high performance pads need to be at 500° F plus to become efficient – just about where stock, OEM pads begin to fade.) Some of this heat is passed onto the brake fluid through the brake calipers, which can raise the fluid temperature to well over 300°F. Fortunately, the boiling point for brake fluid is significantly higher than water. DOT 3 boiling point is 401 °F dry and 284 °F wet. DOT 4 boiling point is 446 °F dry and 311 °F wet. DOT 5 boiling point is 500 °F dry and 356 °F wet. (Wet boiling point defined as 3.7% water by volume.)

    If the brake fluid is repeatedly heated past its boiling point, some of the fluid vaporizes and creates air bubbles within the brake lines. This can lead to a bad and potentially unsafe situation where the brake lines are carrying air instead of brake fluid. Air can be compressed which is why it must be bled out of the systems so that the fluid can properly move the pistons inside the brake caliper and properly operate the brakes. High temperatures also promote condensation (from vapor) and water develops in the lines (ever seen rusty brake fluid?) and this is a huge problem as shown in the above figure – wet boiling point is much lower.

    Fluids don’t compress much (in liquids, there is no gap between particles, so only way you can compress fluid is by reducing the gap at a molecular level, which is effectively changing the state of that material, which involves a lot of energy – but as mentioned, brake lines do flex.

    The advantage to larger lines is greater volume of fluid to dissipate the heat and keep the system well below the boiling point. With DOT 5 fluids, you’d be hard pressed to generate enough heat to boil fluid in a properly operating system – regardless of the line size.
    Dave Severson likes this.
    "Where the people fear the government you have tyranny. Where the government fears the people you have liberty." John Basil Barnhil

  8. #8
    firebird77clone's Avatar
    firebird77clone is offline CHR Member Visit my Photo Gallery
    Join Date
    Sep 2005
    Location
    Hamilton
    Car Year, Make, Model: 69 nomad, 73 charger, 74 vega
    Posts
    3,900

    Quote Originally Posted by rspears View Post
    I'm wondering if it was a formal calculation tied in with wanting to load the front brakes slightly ahead of the rears? Just seems to me that for a given pedal movement/pressure with 3/16" line to the fronts and 1/4" line to the rears, the pressure is going to increase just a tiny bit earlier in the fronts than the rears, just due to the volume difference, but then will equalize. I'm not sure of that, but it kind of makes sense to me.
    I agree, but conditionally:

    It's not volume (do the math) it's that the larger tubing stretches out more, which results in a pressure differential.
    .
    Education is expensive. Keep that in mind, and you'll never be terribly upset when a project goes awry.
    EG

  9. #9
    firebird77clone's Avatar
    firebird77clone is offline CHR Member Visit my Photo Gallery
    Join Date
    Sep 2005
    Location
    Hamilton
    Car Year, Make, Model: 69 nomad, 73 charger, 74 vega
    Posts
    3,900

    Also, in reference to the water vapor comment:

    Brake fluid is hydrophilic. Which means that it will suck water right out of the air. That's why your brake lines get rusty
    .
    Education is expensive. Keep that in mind, and you'll never be terribly upset when a project goes awry.
    EG

  10. #10
    Dave Severson is offline CHR Member/Contributor Visit my Photo Gallery
    Join Date
    Jul 2003
    Location
    Madison
    Car Year, Make, Model: '67 Ranchero, '57 Chevy, '82 Camaro,
    Posts
    21,160

    I believe I'll just use 3/16" line throughout the system, of course making sure I get a master cylinder designed for disc/disc. Thanks everyone for the input! I've always used same size line on race cars and drag cars, I can't see a reason that it won't work just fine on the street. Probably put in a proportioning valve in case tuning brake pressure front to rear is necessary. Appreciate the help!
    rspears likes this.
    Yesterday is history, tomorrow is a mystery, Live for Today!
    Carroll Shelby

    Learning must be difficult for those who already know it all!!!!

  11. #11
    techinspector1's Avatar
    techinspector1 is offline CHR Member Visit my Photo Gallery
    Join Date
    May 2003
    Location
    Zephyrhills, Florida, USA
    Car Year, Make, Model: '32 Henway
    Posts
    12,423

    Will this be a straight mechanical system or will it be assisted in some way?
    .
    Dave Severson likes this.
    PLANET EARTH, INSANE ASYLUM FOR THE UNIVERSE.

  12. #12
    Dave Severson is offline CHR Member/Contributor Visit my Photo Gallery
    Join Date
    Jul 2003
    Location
    Madison
    Car Year, Make, Model: '67 Ranchero, '57 Chevy, '82 Camaro,
    Posts
    21,160

    Quote Originally Posted by techinspector1 View Post
    Will this be a straight mechanical system or will it be assisted in some way?
    .
    I'll be using an 8" dual diaphragm booster. Just a cruizer, I've got to have all the "easy things" for Jackie, ya know? lol
    Yesterday is history, tomorrow is a mystery, Live for Today!
    Carroll Shelby

    Learning must be difficult for those who already know it all!!!!

Reply To Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
Links monetized by VigLink