Brake Problem -- 99 Chrysler LHS -- Please Help!!

Discussion in 'General Motoring' started by Trocilan, Jan 6, 2008.

  1. Trocilan

    Trocilan Guest

    Car has the following symptoms:

    After I drive the car about 12 miles, the brakes slowly sieze up. The
    longer I drive, the tighter they get and the harder the pedal
    becomes. After the car cools off overnight, the pressure gets
    relieved and the brakes loosen again. The front brakes are more
    severely affected than the rear ones (you can tell by trying to spin
    the wheels).

    I replaced the front calipers to no avail. The brake hoses were ruled
    out as the cause of the problem. The Chrysler dealer's mechanics
    didn't feel that the master cylinder or the vacuum booster were
    involved because the problem wouldn't come and go as it does.

    The problem is closely connected with temperature because, one very
    cold day, the brakes froze open. Could only apply them the next day
    when it was warmer.

    Could the ABS (anti-lock braking system) or TRAC (traction control
    system) be the cause of the problem? How can they (or the master
    cylinder or booster, for that matter) be tested?

    Coincidentally, the car started losing engine oil at about the same
    time the brake problem started. Probably no connection.

    If anyone has any idea what is going on, please help! This could get

    Trocilan, Jan 6, 2008
  2. Trocilan

    maxpower Guest

    If the master cylinder was contaminated with an oil base substance such as
    motor oil it will cause the seals to swell up in the system and will cause
    the brakes to seize up. The first clue would be the master cylinder cap
    inside seal. If the seals are swelled up, the system was contaminated. If
    the vehicle was in an accident the firewall could be bent and causing the
    pushrod in the master cylinder to apply pressure causing the brakes to
    seize. When the problem occurs, loosen up the master cylinder as the wheels
    are off the ground and see if the wheels free spin.

    Glenn Beasley
    Chrysler Tech
    maxpower, Jan 6, 2008
  3. Trocilan

    Steven Stone Guest

    Were the replacement calipers rebuilt or new ?
    I had some unusual problems with caliper lockup when the piston seal
    (in this case a square rubber o ring) hardened up from age.

    I also had the same problem with some rebuildt units.
    Steven Stone, Jan 6, 2008
  4. Trocilan

    Bill Putney Guest

    We've recently seen multiple posts on the 300M Club forums of this kind
    of problem. Onset was with freezing weather. I'm convinced that it
    definitely has to do with the cold, and is one of two things:
    (1) Water accumulated in the booster is freezing and interferring with
    proper operation (internal valving). It is a known fact that water does
    accumulate from condensation inside the booster (every time you use the
    brakes, it "breathes" in some outside air - the moisture in the air
    condenses out and accumulates a significant amount over time - anyone
    who has replaced a booster can attest to this).
    (2) Wear in the booster valving causes the sealing of the parts against
    each other to be marginal - and temperature dependent.

    The more likely cause is (1). You could probably pull off water with a
    syringe and plastic tube thru the vaccum hole after removing the check
    valvae, but I don't think there is any way to remove water out of the
    rear chamber. Probably the best solution is to replace the booster with
    a rebuilt one (around $85 at most auto parts stores - NAPA uses the same
    rebuilder as everyone else, but charge around $105 for theres, so in
    this case, migh tas well get it from somewhere else).

    BTW - booster failure from wear that manifests itself in warmer weather
    *can* in fact be intermittent. I experienced it myself on my '99
    Concorde (mechanically same car as the LHS) - replaced booster, problem
    gone. But I think your problem is temperature related due to the
    accumulation and freezing of water.

    Bill Putney
    (To reply by e-mail, replace the last letter of the alphabet in my
    address with the letter 'x')
    Bill Putney, Jan 7, 2008
  5. Trocilan

    Trocilan Guest

    Thanks very much for the replies. I will show them to the mechanic in
    a couple
    of days.

    I presume the calipers were new...I was *charged* for new parts...

    If you (Mr. Beasley) mean the cap on the brake fluid reservoir, I
    looked there
    and its seals were not swollen. If you mean something else, the
    will know what you are talking about.

    On a whim, I started the car, checked to see that the brakes were
    *not* siezed
    up, then let the car warm up without pressing the pedal. Sure enough,
    later, the brakes were seized up even though I had never touched the
    pedal. The outside temperature was well above freezing, maybe 40-50

    Thanks again for your help. I will give all replies to the mechanic
    when I
    take the car back.
    Trocilan, Jan 7, 2008
  6. Trocilan

    Bill Putney Guest

    I'm realizing now that you had two opposite situations (I only caught
    the "no brakes" situation when I replied the first time): One in which
    the brakes were seized up - I now take that to mean that at least one
    wheel was hard to turn (brakes applied), and the other situation in
    which the brakes would not apply. There may or may not be two root
    causes, but it is possible that the booster could have caused one or
    both (due to internal valving problem(s)). If you get the "brakes
    seized up" problem again, see if you can turn that problem off by
    disconnecting and plugging the vacuum hose to the booster - if you turn
    the problem on and off by connecting and disconnecting the vacuum hose,
    then it definitely is the booster. BE AWARE THAT YOU WILL ESSENTIALLY

    Also, maybe it is possible there is water in the brake lines themselves
    (expanding at times, blocking pressure at other times). That's a WAG
    for a possibility. But I've got to think either that or booster problem.

    Bill Putney
    (To reply by e-mail, replace the last letter of the alphabet in my
    address with the letter 'x')
    Bill Putney, Jan 8, 2008
  7. Trocilan

    Trocilan Guest


    Success! (I hope...It has been less than 24 hrs.) I had the brake
    lines flushed and refilled with new fluid and the problem has not
    recurred so far. The tech did note that, while he was pressure-
    bleeding the rear brakes, the front brakes seized up a little. He
    thought the proportioning valves might need replacement. Also, he
    recommended I bring the car back to test the ABS. I'll certainly do
    so if the problem comes back but, for now, I'm just going to drive!
    The brakes seem to be working fine now.

    Thanks for all your help!

    Trocilan, Jan 11, 2008
  8. Trocilan

    philthy Guest

    if oil was introduced into the master cylinder
    the pedal would become hard to push once then after the seals let loose then
    the pedal could be pushed to the floor and the brakes would not work very
    good almost like a bad master cyl.but would yoy would still feel some
    i have had the headaches of figuring this out 3 times on cars in the last 2
    philthy, Jan 13, 2008
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