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  1. #1

    Default almost too much brake power now

    We are running a 85 continental MC with cobra brakes, and a leaking 86 Booster,
    We put the 93 cobra booster in after some serious massaging it fits.

    Holy crap this thing stops insanely fast, it is going to take some time to get used to it.
    I wish I had anti lock brakes now too.
    Anyone add those in? Would it be a PIA?

  2. #2

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    Quote Originally Posted by toddf View Post
    We put the 93 cobra booster in after some serious massaging it fits.
    Even "serious massaging" is, imho, a massive understatement.
    Get out the 400-ton wrecking ball to bash in the strut tower (cough, cough. I mean to clearance it - lmao!).
    But first, clean the wrecking ball with sanitizer, in case Miley Cyrus was grinding on it before.






    Btw, I welded the folds on my strut tower after the clearancing.

    As for the ABS, imho, it's now simple, since you can get the needed associated mating connectors from the wiring harnesses from many cars. And, of course, LMR even sells some.

    Most front hubs should have the ABS rings.

    You need the sn95 rear axles.
    If the rear axles didn't already have the ABS tone rings on them, you can likely still buy the ABS tone rings for the rear axles from Ford, or on ebay.
    Btw, you do not heat the ABS tone rings up to put them on - just press or gently-bang the rings on using some wood between the hammer and the rings. Heating up the ABS tone rings would effect their magnetic properties, and would likely cause the ABS sensors to not function correctly (detect/react-to the gaps in the ABS tone rings).
    Also, to make sure the ABS tone rigs are placed correctly, measure how far the ABS tone rings are from the flange.


    I don't see the sn95 ABS install on a Fox body article on corral.net anymore.
    Here is an archived version:
    https://web.archive.org/web/20180428...dling/abs.html



    For some more info see:
    http://www.veryuseful.com/mustang/te...sDiagInfo.html




    Good Luck!
    Last edited by stangPlus2Birds; 03-25-2020 at 09:31 PM.

  3. #3

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    well ........... you could try playing with master cylinder size.

    A buddy has the exact same brake setup on his 86 with a stock booster and a 1 1/8" SVO master cylinder. The brakes come one VERY early in the pedal movement. There's almost no modulation at all before the front brakes attached to his 255/40/17's reach lock up. Dialing in more rear brake only makes all four put on a smoke show.

    You get used to it after a while, but its not a lot of fun on a road course like that.

    When you say continental MC I assume you mean a 1" bore master cylinder similar to M1858 if not a M1858? The symptoms sound like you are at 1 1/16" or 1 1/8" with a cobra booster.

    In my experience, if you don't get enough pedal travel you need to down a size on master cylinder bore. As the pedal travel increases the amount the booster helps out goes down.

    I am a bit puzzled by what you're experiencing, curious on bore size of the master cylinder.

    Look at that first. A 1" is about right with those brakes-- usually. BUT, and this is a big BUT..... if you prefer to use a lot of brake pedal pressure before lock-up you might have wanted a stock foxbody booster instead.

    If you are at 1" possibly something around a 15/16" bore like an SN95 master cylinder would solve it. Not sure!

    The other ???? in my mind is how darn much vacuum is your engine producing. If you have more vacuum than you need you'll experience some "over boosting" vs what you're expecting. Not a common problem as most cars with beefed up brakes also have a lumpy cam that barely makes enough vacuum for power brakes.

    I run SN95 brakes with a stock booster and 1" bore master cylinder on my 86GT. The brake pedal feel is exactly how I like it. It takes a firm stomp to a practically standing on the pedal to lock mine up. My car stops better than any other car we own -- including our new Continental.

    I'd say a quick call to Maximum Motorsports may prove beneficial is figuring out what to plan out for your next move.

    Good luck!

  4. #4

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    I have a pretty healthy cam .550, I haven't tested vacuum but I don't think I have too much.
    I am thinking going from a leaky stock booster ( manual brakes ) to a giant working one will take some getting used to.
    The towncar MC is a 1" bore.

  5. #5
    FEP Supporter Broncojunkie's Avatar
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    If your brakes are coming in as soon as your foot touches the pedal, I would think that you may just need to adjust the rod so that it's a little shorter.i was having a similar issue with my pace car after upgrading the entire brake system, however, there was another issue with mine. As the engine compartment temp went up, the brakes would start dragging.
    79 Pace Car - 331, t5
    79 Cobra - working on 351w, t5
    86 coupe - rotbox roller
    86 coupe - working on 408w, c4
    88gt - 302 efi, t5

  6. #6
    FEP Senior Member OX1's Avatar
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    Quote Originally Posted by Broncojunkie View Post
    If your brakes are coming in as soon as your foot touches the pedal, I would think that you may just need to adjust the rod so that it's a little shorter.i was having a similar issue with my pace car after upgrading the entire brake system, however, there was another issue with mine. As the engine compartment temp went up, the brakes would start dragging.
    That is not going to make them more progressive, just going to make them do nothing at first, then move the grabby feeling down the brake stroke some.
    86 Capri, 5.0, 5Spd, A9L QH/BE, 47 lb Inj PMAS 3" MAF, Single T44 Turbo, Front Mount IC, TW170,
    Stock Cam, Explr Intake/TB, 1.7 Rockers, CF dual friction clutch, 3" DP, 2.5" full Exh, 3.27, 11.932 @ 115.78
    84 LTD, 331-10:1, TW170/Exprl Intake, 47 lbs inj/80 mm LMAF, Full Duals, Quarterhorse, Vortech 7PSI, Lentech AOD, 5 lug Mk VII brakes/rear, Eibach Sway bars, Cobra HB (dads ride, but I fix it )

  7. #7

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    Booster loses effectiveness later in its stroke so there is some progressiveness to be had by adjusting the rod. It should be checked any time you swap out master cylinders to make sure it’s right

  8. #8

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    Throw away the piece of **** SN95 booster and reinstall a properly functioning Fox 152mm dual diaphragm booster. The brake modulation will be so much better, you will no longer need ABS. You can also change the brake pads to the lowest friction models that you can find. That will help things, but doesn't fix the underlying problem with this booster.

    We built a Fox car a few years ago which had an SN95 booster in it. We told the customer that we should change it back to a Fox booster, but nooooo. The booster in the car said Cobra on it, so we had to keep it. We experimented with different m/c to get the least bad brake pedal. A 15/16" worked best best. The pedal effort is of course even lower, but at least the brakes didn't lock up until there was some pedal travel. With a larger m/c, the pedal effort was higher, but the travel was so short, it was impossible to modulate.
    Jack Hidley
    Maximum Motorsports Tech Support

  9. #9
    FEP Senior Member 854vragtop's Avatar
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    I just did the Cobra brake mod on my '85 Mustang a few months back. I used a rebuilt " '93 Cobra booster " (which is an SN-95 booster with the studs cut off and re-welded on with the correct threads and positioning). I'm also using the 1.00" bore dia '85 Town Car M/C. I'm also using the HAWK 5.0 brake pads at all 4 corners. At first I thought that it seemed way over boosted. But as I drove it around for awhile and really seated the pads in, it doesn't seem over boosted at all. Very natural feeling to me and it doesn't seem that different from my old 73mm Lincoln caliper/ 1.250" SVO m/c setup. Even after you've bedded in the brake pads with the 8-10 stops, keep driving it for a week or so to really get the pads to seat in better. I'm very happy with my setup. I tried using my stock '85 booster with the '85 Town Car m/c, but it was just waaaaay to stiff of a pedal for me.
    '85 Mustang convertible GT, 5 speed, 4V
    Stock bottom end, Comp Cams XE264HR-14, GT-40P heads w/ Alex's springs, Weiand 8124 Street Warrior
    8.8 Turbo Coupe rear end w/ 3.55 gears, '94/'95 Cobra brakes, '85 Town Car M/C, '93 Cobra booster, MM Panhard bar.

    '68 Mercury Cougar, w/ '88 5.0L, 4V
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  10. #10
    FEP Power Member David Claflin's Avatar
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    Quote Originally Posted by Jack Hidley View Post
    Throw away the piece of **** SN95 booster and reinstall a properly functioning Fox 152mm dual diaphragm booster.
    Is there certain years for those type?
    1990 Red LX, ported explorer heads and intakes, weenie cam, 1 3/4 long accufabs, 3" exhaust, T5, 4.88
    1985 LTD LX, Mach1 brakes, 17" Mopar police car wheels. 7.86@86MPH with 302, 3640 pounds with 1/4 tank of gas and me in it. 331 build in progress
    1984 LTD station wagon, with 84GT nose, some might remember it as the old Dugan Racing station wagon.
    1986 FHP coupe, yet another work in progress

  11. #11

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    David,

    From 1987-93 on V8 cars and 2.3l convertibles. Also on SVO Mustangs. They may have been used on some 1985-86 cars, but I have inconsistent data on this. These boosters measure about 6.5" thick down the centerline.
    Jack Hidley
    Maximum Motorsports Tech Support

  12. #12
    FEP Super Member gr79's Avatar
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    Dual diaphragm boosters.
    My 2.3 Ranger 2wd has one. 6.5 thick with 1" bore m/c, 10.2" rotors, semi-metallic pads.
    9" rear drums. Same shoes fit my car and truck.
    Same booster as some F series, Bronco, Explorer.
    Great stock brakes from day one.
    Single diaphragm boosters are thinner.
    Last edited by gr79; 04-06-2020 at 10:25 PM.

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