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Brake Problems - Fix it, or don't drive!!!

Subject: Brake Problems - Fix it, or don't drive!!!
From: (James Fischer)
Date: Sat, 17 Feb 1996 13:00:01 -0500 said:

>> The brakes work well but brake pedal travel is excessive (pedal travels 
>> over half-way before it's solid).  

    This is NOT "working" at all, since one can encounter situations 
    where the first pump on the brakes is the only chance you get to 
    avoid a collision, a ditch, whatever.  This is BROKEN!!!

>> Pedal travel is normal/short after one or more pumps of the pedal.  

    Air.  Clearly air.  The first pump compresses the air, the second
    operates the brakes.  Subsequent pumps within a short period are
    "good", but if you wait a bit, you must start the cycle over again.
    There is air, Air, AIR in the system!!!!!

    Get it out.  Bleed an entire bottle of brake fluid through the 
    system just to be sure.  Keep going until you see brand new, 
    clean fluid, and nothing BUT brand new clean fluid.  Get one 
    of those fancy plastic bottles with the tube attached and the 
    one-way valve, or at least the tube with one-way valve.

>> The DPO says he just got used to always giving the pedal a pump to bring 
>> it up.

    Double-clutching, I understand, but double-braking?  The DPO is a
    certifiable insane idiot.  You can never spend too much time or
    money on your brakes.  Ditto for tires, rollbars, and seatbelts. 

>> ...I've bled the system over again, and there are no leaks or
>> loss of brake fluid, but pedal travel is still over half-way to 
>> the floor before it's solid.  After one or two pumps the pedal 
>> is solid with short travel.
        and Chuck Simmers added:

>     It's funny until this thread started I hadn't realised that my '66 
>     Spridget does exactly the same thing. All new brake parts, bled and 
>     bled again, still needs a double-pump to get a firm peddle. Anybody 
>     got any clues?

    and Dave Hall added:

>I to have a similar problem on my 72 MGB/GT.  If I just press once 
>on the brakes while coming to a stop, the response is very slow braking.
>(i.e., not much braking power.)  If I press once, let up, then press 
>again, it gets much firmer, and the braking response is much better.  
>The PO had it in to an MG shop, and they bled and bled and bled, but no 
>difference was never realized.  

    They did it wrong, or they did not do it enough.  Recall that the
    act of pumping on the pedal to bleed the brakes will make the
    problem "go away" for a brief period, since the first few pumps 
    will bring the pressure up.  The test is to bleed, wait several
    hours, and THEN test again.  Anything less than full pressure on 
    the first attempt is still "broken".


        1)  Put the car up on jack-stands, remove wheels and drums, 
            and get four friends, one to watch each slave cylinder.  

        2)  Press on the brake pedal slowly and carefuly (after 
            waiting for the time required to allow the system to 
            "relax", if you used the brakes at all that day) until the
            first person shouts that he sees motion.  Now press more
            slowly, and note the order and relative sychronization
            between shouts from your friends.

        3)  Bleed the cylinder that was the last one to move.  This
            is the likely culprit.  If you have a PAIR that moves
            late, look at the diagrams to see if they share tubing.
            (My Midget has the "dual braking" system, so the tubing
            is more complex than some LBCs).  If all four move at
            the same time, see which one "grabs" the disc/drum
            first, and which one last.

        4)  If the problem persists, replace the rubber brake hoses.  
            All of them.  

        5)  Check the metal brake lines.  On Midgets, these run very
            near the battery, where they can become corroded from
            the white powder you might find around the battery.
        6)  If you must, buy a hydraulic pressure gauge, and attach 
            fittings to be able to place it between the slave cylinders
            and the supply tube.  Pressurize the system with a few
            pumps on the pedal, and force a 2 x 4 between the brake
            pedal and something firm, like the strut-hump on the
            floor of a Midget just under the front of the seat.
            Note the pressure, and wait a few hours to see if it
            changes.  You may find a leak in the metal tubing.
            If the gauge is too expensive, try putting the car
            up on jackstands, apply the 2 x4, and check each tire 
            by trying to rotate it until you find one that will 
            turn before the others.  This could show you a leak.

        7)  Consider paying for a specialist mechanic's best 
            efforts.  Find one that does NOT also sell tires 
            and mufflers.  If the mechanic is a male, a grey-
            haired pipe smoker is always a good choice, since
            he will stop, light his pipe, and THINK about what 
            he is working on.  Never let anyone younger than
            the car work on the car, unless they can prove
            their expertise by showing you their grease-stained,
            dog-eared shop manual, and their favorite modified
            or specialized tool for a specific task on an LBC.

        8)  If the problem STILL persists, rip out all the metal
            tubing and replace it.  Complete kits are available.
>Hmm..  Perhaps it's another MG mystery?

    No, it is a dangerous error in judgement!!!  If your MG won't go
    (or as I like to say - "declines to proceed"), you can walk home.
    If your MG fails to stop, you can find out first hand why newer
    cars have airbags, compressible steering columns, and all the other
    safety features added since MGs were new.  This education is at
    least hazardous, and can be fatal.

    If you want to own, restore, and drive an LBC car, understand that
    failures such as these are the MOST important problem to address,
    since they can result in all your work and investment being reduced 
    to scrap metal faster than you can press the pedal the "2nd time".

    OK, enough rabid screaming.  Just don't drive behind me until
    you get it fixed, OK?

            james fischer 
            (who's brake pedal never gets anywhere near the firewall)

       No software will ever be able to compress information to the 
       extent a human female does when she merely raises an eyebrow.
 james fischer             

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