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Brakes GRAB and OOOOOOPS

Discussion in 'The Hokey Ass Message Board' started by edljames, Sep 3, 2009.

  1. edljames
    Joined: May 2, 2008
    Posts: 232

    edljames
    Member
    from OK

    Need brake help - when I hit a hard hole or dip with left front wheel the disk brake grabs hold long enough to make me mess my pants. This is a 76 Pacer rack and pinion on my 36 Chev. Tried bleeding and new brake hose on left front (thought it might be getting pinched) - Anyone know a possible fix for this problem (other than a diaper). Thanks
     
  2. Hyway Hauler
    Joined: Aug 31, 2009
    Posts: 670

    Hyway Hauler
    Member

    maybe a piece of s**t that was in the caliper that got jard loose when you hit pot hole, and its hanging up your brakes.
     
  3. edljames
    Joined: May 2, 2008
    Posts: 232

    edljames
    Member
    from OK

    Thanks
    Will try cleaning cyl and calipers again. Just happens occasionaly on a hard dip or hole - I work hard at missing them
     
  4. Arthur1958
    Joined: Jun 29, 2009
    Posts: 230

    Arthur1958
    Member

    I don't think it's just dirt. That sounds serious and potentially dangerous. Check all the attachment points on the rotor and caliper. Also look for stress cracks or other signs of weakness in the spindle assembly. You have probably already examined the brake pad; but, if not, check to see if it has come un-bonded from the metal backing.
     

  5. jamesgs4
    Joined: Aug 22, 2007
    Posts: 253

    jamesgs4
    Member
    from denver

    how do you know its your brake grabbing? does the wheel skid? could it possibly be a suspension issue? like a bad ball joint or loose steering arm?
     
  6. 40chevythrowensparks
    Joined: Aug 16, 2009
    Posts: 100

    40chevythrowensparks
    Member

    i had that issue with my 40 chevy.... when i was mocking everything up i just put a light coat of grease on the spindle bearings...well i forgot all about them... 14 miles later the right side locked up and made me damn near crap my pants...
     
  7. edljames
    Joined: May 2, 2008
    Posts: 232

    edljames
    Member
    from OK

    Thanks for the help guys
    It takes a very hard hole or dip for this to happen and the wheel does skid just for a split seccond. I will pull the wheel and check pads spindle and bearings again tomorrow. - did all these about a year ago and thought I cured it - think I have just been missing the big dips and holes since.
     
  8. 49ratfink
    Joined: Feb 8, 2004
    Posts: 18,093

    49ratfink
    Member
    from California

    I can't see how suspension movement could cause a brake to grab.

    This is a 76 Pacer rack and pinion on my 36 Chev

    complete Pacer suspension or just the rack?
     
  9. edljames
    Joined: May 2, 2008
    Posts: 232

    edljames
    Member
    from OK

    It is complete pacer suspension with ps. All I could afford at the time and has worked great except for this issue.
     
  10. 34toddster
    Joined: Mar 28, 2006
    Posts: 1,482

    34toddster
    Member
    from Missouri

    Is the brake hose being pinched?when you hit that monster pot hole. You might want to replace the hoses also!
     
  11. 61falcon
    Joined: Jan 1, 2009
    Posts: 772

    61falcon
    Member

    are you sure the tire or rim isnt contacting something, like the under side of the fender or maybe a suspension component or frame rail. i find it hard to believe the brakes would momentarily grab due to a pothole or dip in the road.
     
  12. edljames
    Joined: May 2, 2008
    Posts: 232

    edljames
    Member
    from OK

    Me to 61falcon - I am going to recheck everything tomorrow. If it is rubbing or hitting something I should have seen the mark cause I looked quite awhile - I will look again tomorrow. Thanks
     
  13. jimbo121
    Joined: Jun 15, 2006
    Posts: 126

    jimbo121
    Member

    How fast do you need to go for this to happen? If happens when u are going slow you could try clamping off the hose on that side to eliminate a hydraulic fault. I wouldn't recommend doing this if you have to drive at speed though as only 1 front brake would be dangerous. Just my 2cents.
     
  14. BigBlockMopar
    Joined: Feb 4, 2006
    Posts: 1,360

    BigBlockMopar
    Member

    Try posting some good and upclose pics of the setup, maybe someone can spot something fishy in the pics you might have missed.
     
  15. fuzzface
    Joined: Dec 7, 2006
    Posts: 1,319

    fuzzface
    Member

    When you jack it up tomorrow, Jack it up by the frame and not by the suspension. Leave the suspension and brake hoses hang down to see if there is something you are overlooking that you might see this way.
     
  16. Pacers have multi-piece spindles. Make sure that all four bolts that hold the spindle stud, upright, brake caliper bracket and steering arm are in excellent condition and are torqued to spec.

    Also, how about a good return spring on your brake pedal? The shock from the pothole could be applying your brakes for you.
     
  17. auto shop
    Joined: Aug 20, 2005
    Posts: 284

    auto shop
    Member
    from kentucky

    Could the tire be hitting the fender brace and making the tire skid?
     
  18. dalesnyder
    Joined: Feb 6, 2008
    Posts: 465

    dalesnyder
    Member

    Extremely bad wheel bearings or maybe the tie rod end hitting the tire? Whatever it is it should leave a pretty good mark when you get the wheel off and look at it..Back side of the caliper hitting something and forcing it toward the wheel locking up on the rotor.. ?
     
  19. edljames
    Joined: May 2, 2008
    Posts: 232

    edljames
    Member
    from OK

    Thanks for all the great input - I will do most of above and post when I get done. I believe I have generally been going in 30-50 range on a back road when it happens - takes the right speed and right bump. Do have one on a road near my house that I avoid because I can MAKE it do it there. Don't think I want to try the clamp off method but if nothing else works I will clamp off both front wheels and see if I can get it to do it. Will take some pics as well. Thanks again - now I will try to getrdone.
     
  20. scottybaccus
    Joined: Mar 13, 2006
    Posts: 4,109

    scottybaccus
    Member

    Is the bump jarring the car hard enough to sling the brake pedal and momentarily apply the brakes?
     
  21. edljames
    Joined: May 2, 2008
    Posts: 232

    edljames
    Member
    from OK

    Scotty
    If that was the case wouldn't it effect all brakes - not just left front? Will try to get to it today but got some Honey dos first.
     
  22. edljames
    Joined: May 2, 2008
    Posts: 232

    edljames
    Member
    from OK

    OK -Here are some pics -need to mail order parts before teardown - need the car this weekend - been in rebuild and paint last 6 months - the current brake hose was replaced prior to that and thus the new paint and polish compound you see. I have bled brakes (new mast cyl/vac)
    No marks or scuffs anywhere on fenders tires etc. - think that means spindles or brakes - a little drag of rotor while suspended but not nearly enough to cause grab. If it was hitting fender it would hit top brace first and no marks there.
    Brake pedal has a spring and I believe if it was peddle I would get both front wheels grabing. You guys see anything I am missing before teardown, Right now I am thinking everything - bearings - pads - brake line - turn rotor - calipers -etc. which should cure it but would be nice to know the exact cause. Thanks again for all the suggestions.
     

    Attached Files:

  23. 52pickup
    Joined: Aug 11, 2004
    Posts: 833

    52pickup
    Member
    from Tucson, Az

    Is that sway bar link touching the caliper?
     
  24. scottybaccus
    Joined: Mar 13, 2006
    Posts: 4,109

    scottybaccus
    Member

    Not necessarily. If one rotor and caliper is a little grabby, you may not notice the other being applied.

    Bigger concern. All that paint on your brakes and suspension was a real fuck up if it was applied to the assembled parts. (looks that way)

    Paint getting into all the clearance areas, such as caliper guide pins, caliper piston, edges of pads, pad surface, rotor surface, etc. can create all manner of misbehavior. You need to tear it all down and clean it, turn the rotors maybe, throw out the pads if they were used to clean paint off the rotors... You get the idea.
     
  25. edljames
    Joined: May 2, 2008
    Posts: 232

    edljames
    Member
    from OK

    My painter didn't cover the parts
    52pickup - there is a good 1" clearance to caliper and no marks on caliper.
    Scotty - I am hunting down the parts for both sides and I will clean the paint,
    Thanks everyone for the education on things I never thought about. Will let you know when I get done.
     
  26. edljames
    Joined: May 2, 2008
    Posts: 232

    edljames
    Member
    from OK

    The brakes clipers and pads were all in good shape - There was a missing clip (holds pads in place) on the left front and I put on a new clip - I have not been able to get it to grab since so I believe that cured it. My dad used to tell me "it is normally something simple" when you have any malfunction. To bad I didn't listen good.
     
  27. tommy
    Joined: Mar 3, 2001
    Posts: 14,757

    tommy
    Member Emeritus

    Does it pull during normal stopping or just when you hit a pot hole?
     
  28. edljames
    Joined: May 2, 2008
    Posts: 232

    edljames
    Member
    from OK

    tommy - never had a pull problem - just a grab with a hard pothole - just enough to make the tire skid very quickly.
     
  29. tommy
    Joined: Mar 3, 2001
    Posts: 14,757

    tommy
    Member Emeritus

    In that case I'd be checking the suspension, bearings, etc. I've never encountered a situation where a bump would cause one wheel brake to apply itself. It's very odd to me. You might try putting that side on a jack stand under the ball joint, remove the tire and get a heavy neighbor to cycle the suspension by jumping up and down on the bumper and see what is happening.
     
  30. edljames
    Joined: May 2, 2008
    Posts: 232

    edljames
    Member
    from OK

    it was weird - we checked everything - tried the jack stand and jumping. I believe the missing clip let the pads bounce in a some way to make them grab for an instant - any ways it seems to be fixed, Course I did most of the things mentioned above as well and one of those could have been the trick but I think it was the clip. Thanks for your input. Ed
     

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