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GMC brakes repair questions and answers

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  • AutoMD Member
    AutoMD Member - 1998 GMC Savana 3500 - Brakes - 7/12/2014
    What is double flaring of a brake line ?
    Auto parts store told me to double flare the brake line . How do I do that , and why ?
     
  • Vicki
    Vicki - 2003 GMC Sonoma - Brakes - 6/16/2014
    Tail light and signal (rear) passenger side do not work, changed bulb but still didn't work. What could it be.
    There is a small box in there what is that called so I can replace it.
     
    • Boe
      6/3/2014 Boe
      it could have something to do with the fuse check those
      next could be the light switch
      james.boden.1@us.af.mil let me know
    • 63 Volvo
      6/16/2014 63 Volvo
      also check the trailer hitch wiring harness
  • olivetree
    olivetree - 2003 GMC Envoy - Brakes - 6/16/2014
    What is causing the brakes to apply themselves on turns only. (left or right)
    When making turns the brakes (what feels like the brakes) apply themselves. If at a very slow rate of a turn, it actually stops the vehicle. I've checked the front rotors, pads, brakes lines, & wheel wells for some sort of visible damage or rubbing & I have found ...
     
    • GT500Knights
      6/16/2014 GT500Knights
      Is your vehicle equipped with 4wd? This might not be possible, but it happened on my car: the electronic 4wd shift motor got stuck into 4hi on my vehicle one time. on my car, 4hi is only meant for off roading where there is loose traction. if 4hi is used on pavement, trying to make turns can damage the differentials--however what i had also noticed is that making turns on pavements drastically slowed down the vehicle. it was fine driving straight. so, this is one possible scenario.

      So when making turns is the braking effect feel like someone is actually stepping on the brakes? Or is the braking effect more gradual? Only other things I could think of would either be alignment severely messed up (toe and/or camber), steering linkage to one or both wheels severely damaged, or differential/transaxle internal damage.
      GT500Knights
      6/24/2014 olivetree
      Thank you for your time & reply.
      Your right it was on 4hi, i've put it back on 2wd & it is running fine
  • olivetree
    olivetree - 2003 GMC Envoy - Brakes - 6/16/2014
    What is causing the brakes to apply themselves on turns only. (left or right)
    When making turns the brakes (what feels like the brakes) apply themselves. If at a very slow rate of a turn, it actually stops the vehicle. I've checked the front rotors, pads, brakes lines, & wheel wells for some sort of visible damage or rubbing & I have found ...
     
    0 answer
  • Kentrell
    Kentrell - 2003 GMC Envoy - Brakes - 6/3/2014
    When on brakes acts as if it wants to cut off
    This only happens when the air is on, at a stop sign when I apply the brakes the car jerk and it sounds as if it wants to cut off but it doesn't. 168,000 miles and it happens all the time when I stop and the air is on, The check engine light is not on
     
    • Boe
      6/3/2014 Boe
      you have a vacuum leak some where check the hose from your brake booster to the engine
      james.boden.1@us.af.mil let me know if you have any questions
    • Chevy doctor
      6/3/2014 Chevy doctor
      I would have your belt and tensioner checked. Another issue is the fuel pressure regulator leaks fuel through the vacuum hose. Pull off vacuum hose and check for fuel. These are the most common issues.
  • cheandrews60
    cheandrews60 - 2005 GMC Sierra 1500 - Brakes - 6/3/2014
    When use the brake my truck hesitates to stop and I hear a grinding
    160 000 kms. all the time when using brakes I disconnected a wheel sensor (I think) and it didn't happen again until I reconnected it a code reading was done the machanic said he got 2 readings but couldn't tell what was the problem he said it could be electrical ...
     
    • Boe
      6/3/2014 Boe
      you have bad ABS sensors you will have to get the wheel hubs replaced \
      james.boden.1@us.af.mil let me know if you have any questions
  • AutoMD Member
    AutoMD Member - 1995 GMC C1500 - Brakes - 5/20/2014
    Do I have a bad ABS unit?
    I have done some recent repairs to this truck. I had to run some new brake line also. I can bleed the brake system, and get good brake pressure. After sitting for a couple of hours, there is no brake pressure. You can get some of the pressure back by pumping the ...
     
    0 answer
  • AutoMD Member
    AutoMD Member - 1995 GMC C1500 - Brakes - 5/20/2014
    How do you tell if the ABS unit is bad?
    The brakes have been bled numerous times. They work well when I am done. After shutting it off and sitting for a couple of hours, the brakes have no pressure. You can get brake pressure by pumping the pedal, but it will fade. I can detect no leaks in the lines ...
     
    0 answer
  • AutoMD Member
    AutoMD Member - 2001 GMC Jimmy - Brakes - 4/21/2014
    There is a clicking like a turn signal?
    After we put new brakes and pads on it started this clicking sound.
     
    0 answer
  • AutoMD Member
    AutoMD Member - 1989 GMC K1500 - Brakes - 3/8/2014
    Manuel 5 speed. when ingaged in reverse, rear brakes seem to be dragging.
    My clutch needs replaced possible throw out bearing going could that cause any problems?
     
    • HouseCallAuto
      3/8/2014 HouseCallAuto
      Maybe the parking brake cable is stuck partially on because of the cable being rusted and siezed. Maybe the rear brake shoes were installed backwards
  • earl
    earl - 1996 GMC C1500 - Brakes - 2/25/2014
    Brake pedal goes to floor while braking
     
    • Team Associated
      3/21/2011 Team Associated
      Air in the brake system – bleed the system

      2. Grease or something on the brake shoes – remove the rear brakes and look for fluid on the shoes or drums

      3. Low (worn out) rear brake shoes, or a problem with the self adjusters in the rear brakes

      4. A problem with the master cylinder – replace master cylinder

      5. Brake fluid distribution problem – make sure there is enough brake fluid going to the rear brakes – check diverter valve
    • smagic69
      2/25/2014 smagic69
      check your brake fluid if its low fill it up to the max and then have someone hit the brake pedal for you so you can get underneath the truck and look where there could be a leak or it could be the brake booster but id go with the first one
  • jimt
    jimt - 1997 GMC C1500 - Brakes - 2/23/2014
    How do you tell if the master cylinder or the booster is bad on my 97gmc truck
    Pedal goes almost to the floor but stops
     
    • HouseCallAuto
      2/23/2014 HouseCallAuto
      Its likely caused by neither one. The brakes have to be checked, in particular the rear brakes if they are drum type brakes. Is the brake fluid level low?
  • AutoMD Member
    AutoMD Member - 2000 GMC Yukon XL 1500 - Brakes - 2/13/2014
    Why is my rotor grinding? Why are my breaks going to the floor? Why is my driver side tire locking up?
    Grinding like metal to metal sounds. Clacking in driver side front tire. Abs light on. Breaks slipping
     
    • Jimm
      2/10/2014 Jimm
      Sounds like the front disc brake pads are worn down to metal-on-metal. If this is the case, then not only will the front brake pads need to be changed, then the brake rotor(s) will need to be changed as well.

      Remove the front wheels for a thorough inspection and to determine which replacement parts are needed.

      The parts are readily available from these many on-line sources, www.partsgeek.com, www.rockauto.com, www.discountautoparts.com, www.autopartswarehouse.com, www.jcwhitney.com - to list only a few possibilities.
      In fact, they (RockAuto) list the front disc brake pads (axle set = both sides) from around $10.40, and the front brake rotors from around $22.70 (each) for your vehicle.
    • HouseCallAuto
      2/10/2014 HouseCallAuto
      It is not your brake pads or the rotors that need service, well at least not for what you have detailed here. What you are experiencing is known as "false abs activation" and is not uncommon to happen. The cause is one of your front abs wheel speed sensors is junk and the computer that activates your abs (that clicking in the pedal and the sinking pedal is active abs) thinks that your tire is hitting ice or is in a skid when you are not and this is happening because the sensor is throwing out signals that it is. It is giving the abs computer false info and the compter is then activating. You have to determine which front abs sensor is the cause and in a shop this is determined by one of two methods. Jack up each front tire one at a time and the wheel bearing that has end play is the bad one -HOWEVER - the hub bearing (which is acytually the abs sensor) does not have to have any feelable play so this test is not foolproof. The other way is to read fault codes on an abs capable scan tool and the code will identify the affected wheel, but you do not have this scanner and autozone will not check abs codes for you..got it? This type scan tool can be purchased online maybe for as cheap as $150 if you are still in this game...are you?
    • fazio auto
      2/13/2014 fazio auto
      Probably extended the caliper too far and one side may be locked up
  • AutoMD Member
    AutoMD Member - 2000 GMC Yukon XL 1500 - Brakes - 2/13/2014
    Why are my breaks going to the floor? Why is my rotor scrubbing?
    Breaks slipping. Abs light on. Grinding like metal to metal sounds. Loud rough clacking. Front drive side tire locking up.
     
    • Jimm
      2/10/2014 Jimm
      Sounds like the front disc brake pads are worn down to metal-on-metal. If this is the case, then not only will the front brake pads need to be changed, then the brake rotor(s) will need to be changed as well.

      Remove the front wheels for a thorough inspection and to determine which replacement parts are needed.

      The parts are readily available from these many on-line sources, www.partsgeek.com, www.rockauto.com, www.discountautoparts.com, www.autopartswarehouse.com, www.jcwhitney.com - to list only a few possibilities.
      In fact, they (RockAuto) list the front disc brake pads (axle set = both sides) from around $10.40, and the front brake rotors from around $22.70 (each) for your vehicle
    • fazio auto
      2/13/2014 fazio auto
      Would venture to guess that your calipers are fully extended and leaking brake fluid. You may need to repair your brakes with calipers, rotors and pads.
  • AutoMD Member
    AutoMD Member - 1992 GMC K1500 - Brakes - 2/11/2014
    Rear brakes lock up when backing. Completely.
    Ive tried adjusting the manual adjustment gear between the shoes. But to get it to stop its so far in, the parking brake goes to the floor with no brake holding. And the brake pedal goes way to far before grabing. The locking up is instant and solid, like something ...
     
    • HouseCallAuto
      2/10/2014 HouseCallAuto
      If this were my job I would replace the rear brake shoes no matter how good they look (unless you already did that) and I would assemble with new self-adjuster repair kits. Diofferent part # for left and right and lastly I would replace or resurface the drums and also confirm that the rear parking brake cables are retracting fully after releasing the parking brake and not over-adjusted. I know this might be replacing more than what is needed to solve it but I want to do this job once and not get married to it. I suspect that the locking up is mostly related to the parking brake - maybe a bad left or right cable that is not retracting fully. Also I will assume that the shoes are not installed reversed, primary (less material on shoe) goes to front and secondary (more material on shoe goes to rear. Also confirm that the wheel cylinders are not frozen by using any suitable tool and pushing inward on the wheel cylinder pistons a 1/4" or so and feel them move easily at all four points. Here is a provedure that I want to try to explain that is not written down anywhere. After the shoes are in place and you feel that the shoes are adjusted correct to the drum, you should be able to grab the bottoms of both the front and rear shoes and pivot the shoes forward and backward like a half inch or so and the point where the top of the shoes touches the anchor pin should remain in contact with the anchor pin (the anchor pin is the top most stantion / pin) as the shoes move forward and backward. if the shoes lift away from that anchor pin as soon as you start to pivot the shoes then the parking brake lever is not retracted fully which causes the parking brake crossbar to become a fulcrum point as you pivot the shoes. Ok that might be confusing but maybe not.
      HouseCallAuto
      2/11/2014 AutoMD Member
      Thats the best answer I've heard from anybody. Incld my mechanic. I went to buy the rebuild kit even before I read ur answer. The one they said went to my vehicle had a large adjustment wheel, (approx 1" dia). Mine is only slightly larger than the threaded rod it spins on ( approx 3/8"). Has this just been updated over time? Or maybe not the correct kit. Also the only rear pkng cables they show are for extended cab, mines a standard cab, are they the same? Your answer is awesome
    • John's Auto Repair
      2/10/2014 John's Auto Repair
      Are you sure brake shoes aren't contaminated with brake fluid or gear oil?
      John's Auto Repair
      2/10/2014 HouseCallAuto
      I forgot that. Yeah of course.
    • HouseCallAuto
      2/11/2014 HouseCallAuto
      So you need to buy the "self-adjuster repair kit" as it is called and apparently your truck has 10" brakes as opposed top the 11" brakes they gave you the kit for that was wrong. The 10" brake kit has a much smaller star wheel diameter like you described.
 
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