Register now to get rid of these ads!

Technical Mustang II Brakes will not stop OK keyboard Mechanics your time to shine

Discussion in 'The Hokey Ass Message Board' started by hotrodhomework, Aug 21, 2019.

  1. Mr T body
    Joined: Nov 2, 2005
    Posts: 2,228

    Mr T body
    Alliance Vendor
    from BHC AZ

    That's way to much ratio and reduces the stroke. Too much ratio, too little vacuum and little else helpful in claiming Hoffman crap is the cause.
     
  2. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,355

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Hoffman crap likely WAS the cause with the initial build. Maybe not so much now after several replacements and alterations.

    Ray
     
  3. wandi harry
    Joined: Jul 19, 2008
    Posts: 321

    wandi harry
    Member

    Thats a huge amount of travel, the pedal ratio will probably exaggerate any free play
     
    sunbeam likes this.
  4. hotrodhomework
    Joined: Aug 23, 2006
    Posts: 99

    hotrodhomework
    Member

    I put the petal ratio back to 5.3 : 1 Did not really make that much difference to have it at 7:1
     
  5. wandi harry
    Joined: Jul 19, 2008
    Posts: 321

    wandi harry
    Member

    I know its basic stuff and you would have done it but when we re placed shoes or messed with brakes go with the ABC , adjust , bleed then check
     
  6. hotrodhomework
    Joined: Aug 23, 2006
    Posts: 99

    hotrodhomework
    Member

    I can come to a complete stop apply the brakes in gear and give it gas and power through. The brakes will not hold the car.
    Now I can get rear brake to lock up if I press the pedal extremely hard say in the 180 to 200 lbs of pedal pressure range. I not going to do any more driving tonight because of the neighbors. I am making a lot of noise. I got to be nice.
     
    wandi harry likes this.
  7. 32v
    Joined: May 20, 2007
    Posts: 952

    32v
    Member
    from v.i.

    master cyl bore too large
     
    49ratfink and 34toddster like this.
  8. hotrodhomework
    Joined: Aug 23, 2006
    Posts: 99

    hotrodhomework
    Member

    Already tried a 1 inch bore low speed stopping got better hi speed stopping worst.
     
  9. hotrodhomework
    Joined: Aug 23, 2006
    Posts: 99

    hotrodhomework
    Member

    Yes it was. I put back to 5.3:1
     
  10. squirrel
    Joined: Sep 23, 2004
    Posts: 55,944

    squirrel
    Member

    I would try no booster, 7:1 pedal, 1" mc bore, and make sure the rear brakes are 10" at least, and the fronts have the right calipers.

    I have very little experience with the little aftermarket boosters, but none of it has been good.

    I do have experience with manual disc/drum brakes, they do work....
     
  11. hotrodhomework
    Joined: Aug 23, 2006
    Posts: 99

    hotrodhomework
    Member

    That is what I wanted to do first but my friend wanted to keep the booster.
     
  12. alumslot
    Joined: Mar 5, 2008
    Posts: 560

    alumslot
    Member

    I just helped a friend with the same problem. We bled almost 3 quarts of brake fluid no AIR no where in the lines still wouldn't stop very hard pedal. All finally did was to make the pin between the booster and the master cylinder about 1/4" longer and had GREAT brakes after that. It worked for him.

    Jim
     
  13. hotrodhomework
    Joined: Aug 23, 2006
    Posts: 99

    hotrodhomework
    Member

    I checked when I changed master cylinder I used the tool that a friend had. Got it at .040 thousands
     
    Hnstray likes this.
  14. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,264

    gimpyshotrods
    ALLIANCE MEMBER

    Are they the kind that has the insert that goes in the piston, that allows it to be used in a manual, or power application?

    If so, do you, or do you not have the insert in there?
     
  15. hotrodhomework
    Joined: Aug 23, 2006
    Posts: 99

    hotrodhomework
    Member

    Inserts are in place
     
  16. I knew from the thread title there would be a Corvette-style master in the mix.
     
  17. QUOTE="squirrel, post: 13213700, member: 3595"]I would try no booster, 7:1 pedal, 1" mc bore, and make sure the rear brakes are 10" at least, and the fronts have the right calipers.
    I have very little experience with the little aftermarket boosters, but none of it has been good.
    I do have experience with manual disc/drum brakes, they do work....[/QUOTE]

    I keep it real simple and my cars stop well. I have an old Ford, GM discs up front, stock 11" drums out back. Manual '72 Mustang 1" bore master and an aftermarket proportioning valve with a rear bias adjuster. I set the push rod length the same as the old master I took out and have never touched the brakes since. The rod is in the stock position for manual brakes. You start putting together parts with no pedigree that do not play well together and you may have a different outcome. A power booster throws another whammy into it, especially the small 7" & 8" ones. I did a swap into a '65 Belair, dual master and drum brakes, I wanted to get rid of the single master and figured power brakes would be cool. I got a rebuilt stock master-booster locally, probably an 11" booster. Guess what, it stopped great.
     
    upspirate and Truckdoctor Andy like this.
  18. Happydaze
    Joined: Aug 21, 2009
    Posts: 1,904

    Happydaze
    ALLIANCE MEMBER

    Where is the intersection between the pedal and the rod to the booster/master relative to the pedal pivot? It wants to be at something like 4 o'clock passing through to about 8 o'clock when the brakes are applied. If it it's set up to start at say 6 o'clock there isn't enough travel applied to the brakes for them to work properly despite the pedal continuing to travel.

    I'm assuming an under floor arrangement and not a swinging pedal.

    Chris
     
    anothercarguy likes this.
  19. Weedburner 40
    Joined: Jan 26, 2006
    Posts: 954

    Weedburner 40
    Member

    You might see if a more aggressive brake pad compound is available for your calipers. We had a similar situation on a car with Wilwood discs all around. Changed to a different pad and made a huge difference.
     
  20. onetrickpony
    Joined: Sep 21, 2010
    Posts: 753

    onetrickpony
    Member
    from Texas

    Did you verify that the calipers were on the correct side? Those symptoms are exactly what happens when air is trapped above the bleeder. Car stops but can't lockup and pedal goes farther down than it should, no air bubbles when you bleed.
     
    Country Joe and Jackalope 325 like this.
  21. LOU WELLS
    Joined: Jan 24, 2010
    Posts: 2,756

    LOU WELLS
    ALLIANCE MEMBER
    from IDAHO

    Excellent Thread And I Actually Learned Something In My Senior Years...Thanks... IMG_0043.jpg
     
    48fordnut and harpo1313 like this.
  22. Jackalope 325
    Joined: Sep 24, 2015
    Posts: 13

    Jackalope 325
    Member

    onetrickpony beat me to it! I fought this on a friend's OT car last fall. After the calipers were replaced, he had the same symptoms as you. After a couple weeks (and 3 gallons of brake fluid) of trying everything, we got desperate and bought a second set of new calipers. Thank god, the helpful girl at the auto parts store wrote "left" and "right" on the boxes...
     
    48fordnut likes this.
  23. 6sally6
    Joined: Feb 16, 2014
    Posts: 2,459

    6sally6
    Member

    Cheap-assed front brake pads.........not 'metallic' not premium not 'ultimate' not the low dust/no dust...the cheapest Pep Boys sells..........are the best stopping pads!! Because they are the softest (I guess). No more miles than we put on these cars they will last for years too.
    Worked for me (and the stepped master cylinder!)
    6sally6
     
    ClayMart and trollst like this.
  24. David Gersic
    Joined: Feb 15, 2015
    Posts: 2,730

    David Gersic
    Member
    from DeKalb, IL

    In addition to everything else, and removing any Hoffman parts, check the pushrod to m/c clearance. Also, after overheating a set of brake pads, they wouldn’t stop worth a damn. Maybe some new pads are needed, depending on the history of the car.


    Sent from my iPad using The H.A.M.B. mobile app
     
    Hnstray likes this.
  25. southcross2631
    Joined: Jan 20, 2013
    Posts: 4,413

    southcross2631
    Member

    I always use a Mustang 2 master cylinder on my disc/drum setups. They are cheap and are designed for your application. I use a speedway adjustable proportioning valve. Never even needed a power brake booster. Using one on my Avatar metric GM rotors and calipers and 11x2 1/2 drums. stops straight and true .
    Used one on my old Morris Minor with a Fatman Mustang 2 setup with Pinto rotors and calipers with drum rears. It had a frame mounted master cylinder , daily driver for 3 years no booster needed. DSCF0954.JPG
     
    48fordnut and catdad49 like this.
  26. Not a ton of room anywhere for a booster!!
     
  27. hotrodhomework
    Joined: Aug 23, 2006
    Posts: 99

    hotrodhomework
    Member

    Yes
     
  28. hotrodhomework
    Joined: Aug 23, 2006
    Posts: 99

    hotrodhomework
    Member

    It is a swing pedal not under floor
     
  29. hotrodhomework
    Joined: Aug 23, 2006
    Posts: 99

    hotrodhomework
    Member

    Y
    Yes the caliber bleeders are at the top of the calipers. First thing I checked
     
  30. hotrodhomework
    Joined: Aug 23, 2006
    Posts: 99

    hotrodhomework
    Member

    That something that we might need to do couldn’t hurt to have a softer set of pads
     

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.