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OT 96 JIMMY BRAKE PROBLEM

Discussion in 'Uncategorized Threads' started by break25, Dec 25, 2007.

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  1. break25

    break25 TS Member

    Joined:
    Jan 29, 1998
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    I have been on this site requesting help a while back and got a lot of help from TRON and others. But what I did not put in writing was the correct PROBLEM DEFINITION as was suggested in another poster's message. AUTO SERVICE MANAGER HELP.

    PROBLEM DEFINITION: POOR PANIC BRAKING. Symptom, Long/Low brake pedal travel before stopping. Takes a while to stop. Only 66K on the car.
    Checked wheel sensors OK. New pads and shoes. ABS work fine and groans when engaged. (Sliding). GM recall installed the ABS which recognizes when in 2WD or 4wd. PS. GM NO HELP. In for the same prob many times never fixed. Said this is how the brakes work.

    Possible assumptions given. Bad Booster? BAD MASTER CYLINDER. However, I have been told " The master cylinder works or it don't work".
    \
    Any suggestions. While getting over your Christmas feast?


    CHAZZ
     
  2. Texas Ton

    Texas Ton TS Member

    Joined:
    Jan 29, 1998
    Messages:
    417
    First, do you have an SES light and/codes?

    No, a master can be leaking by and give some braking-----it isn't that it works or don't.

    How long have you owned it, and has it been like this always?

    The master is the first thing to try, but did this start when the ABS was worked on?

    If so, I think it needs to be bled using a hydraulic brake bleeder by someone who cares about doing it right. If you have the fittings and gauge (2,000#), you can pressure test the master.
     
  3. cmptrwz1

    cmptrwz1 TS Member

    Joined:
    Jan 29, 1998
    Messages:
    165
    Sound like a bad master cylender the the person who told you it works or not is wrong being power brakes and anti lock you would not feel the clyender haveing bleed by because of the above system I would change the cylender and bleed the brakes real good and also check the free play between the brake pedal and the power booster if the play in the shaft is to much may need to replaced or possible adj if it can be but it sound like a bad master cylender to me.
     
  4. break25

    break25 TS Member

    Joined:
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    Thanks, It has always been my gut feeling that it was the Master. I have been willing to go the expense of trying the replacement. Just replaced pads and rear wheel cylinders. So I ass u me that the brakes were BLED. But, still have same problem. One guy wanted to replace the CAT, said it was a vacuum problem.
    The car was purchased in 1999 with 24,120 miles.
    Went under GM extended warranty. Always complained. Have a thick folder of warranty repairs/replacements. Never fixed the problem. They also caused other problems that I don't want to get into.
    I drive very carefully and pump braks to stop. I would never try to sell it to somene as it has been quoted over 1 K to fix.

    CHAZZ
     
  5. Texas Ton

    Texas Ton TS Member

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    Jan 29, 1998
    Messages:
    417
    If you can pump them and get better brakes, put a master on it. Also make sure whoever changed the wheel cylinders put the right size (bore diameter) back on.

    It also could have had the wrong master put on at one time, for this one shot I'd go to a dealer, even an online dealer, give them your VIN# and aquire the correct master that way.

    If you happen to get along with any dealers/shop forman in your area, they can run your VIN and find out at least what has been done to it under warranty.
     
  6. maclellan1911

    maclellan1911 TS Member

    Joined:
    Dec 9, 2006
    Messages:
    4,226
    GMs get the low pedal complaint the highest at our shop. I find a lot of bad fluid. Flush old nasty fluid out. bleed brakes completly. at 10+ years replace the master just for good measure. Stay away from the rebuids go New GM. Also the self adjusters never seem to work in the rear drum systems. I find so many under adjusted drum brakes. Also make sure front caliper pins and pads are not frozen. I have had to bleed some systems several times to remove all the air. If you have any nasty dirty film inside your resevoir, thats through out your system. New master properly bench bled. Do not bottom out piston. flush system, check rear adjustment, check front for frozen hardware. I have seen many inboard pads frozen on the braket. Now the 4wheel disc brake system is even more spungy! good luck
     
  7. maclellan1911

    maclellan1911 TS Member

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    PS remember DO NOT PUMP the brakes when bleeding, down on pedal open bleeder and repeat. never let the pedal go to the floor either.
     
  8. 27hotrod

    27hotrod TS Member

    Joined:
    Jan 29, 1998
    Messages:
    20
    Just experienced the same thing with a '98 Jimmy. Master Cylinder fixed the problem.
     
  9. break25

    break25 TS Member

    Joined:
    Jan 29, 1998
    Messages:
    217
    Well today I had the Brake System Repaired. New front pads and roators, replaced rear Cylinders and brakes,AND a MASTER CYLINDER.
    So far I get good panic stops with the ABS groaning on todays wet roads and a higher pedal. Master was put in last, after taking a test run and did it as matter of taking a shot and clearing my head.


    Costly, but now I can drive it until I can afford another car. Also If I want, I can sell it with a cleares conscience.


    Thanks for all the help.


    CHAZZ
     
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