Announcement

Collapse
No announcement yet.

Rear Brake vibration.

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • [Corsa C 2000-2006] Rear Brake vibration.

    Odd brake problem guys, need your help. Thanks all.

    Wife has an 03 1.2 sxi non abs model.

    Handbrake has never been the best so thought i'd whip of the drums, clean everything up, re-lube all contact areas for the shoes, cleaned out and re-greased the runners for the handbrake cable etc ready for m.o.t time.

    Whilst putting the nsr drum back on the bearing seperated. Not knowing that it just clipped back together I ordered and fitted a new bearing. Used a blow torch on the hub centre to help draw out the old bearing.

    So, new bearing fitted and hub back on. Now there's a really bad vibration when breaking from high speed and even at low speeds you can feel it on the pedal.

    Put it in for m.o.t. and explained the problem to my regular (and very good) m.o.t. tester and he confirmed there was a pulsing on the nsr. Not bad enough to fail it but he could see it on the rollers.

    So I decided I must have warped the drum with the heating/bearing replacement. Ordered 2 new drums with pre-fitted bearings and it's still the same.

    Today I replaced the rear shoes and it's STILL the feckin same!!!

    Now I consder myself to be a pretty goos home mechanic but this has me totally baffled. Had no problem whatsoever until I messed around with things.

    Hubs and wheels all torqued up correctly etc

    Help please guys, it's driving me mad.

  • #2
    A bit weird to say the least.

    First thought is to ask if there's any chance that the shock absorber has failed? Sometimes one on the verge of going lets pop when you jack the car up. A failed shock can show up as vibration on braking. Doesn't usually feel like pulsing though - just worth mentioning.

    The second thing is about the bearing separating when refitting. When the C first came out one of things I didn't like about it was that unlike the B the rear bearings came fitted to the drum rather than just buying the bearings themselves. A lot are still sold that way but you can get just the bearings now. However, they ain't meant to just come out so easily, which makes me wonder if the old bearing has damaged the stub axle at all?

    Bit of a long shot but you've already checked the obvious things.
    1972 Viva restoration thread - http://www.thecorsa.co.uk/projects-b....html#post1534

    Comment


    • #3
      Cheers Taurus. I've tried the old osr hub on the near side and the problem still exists. Not sure it would be the shock either. If driving in 1st and I apply the handbrake the nsr raises and lowers on each revolution of the road wheel as if the brakes are biting then not, biting then not. Does this in reverse too.

      It's got me beat.

      Gonna bleed the rear but can't see that making any difference. I'm clutching at straws.

      Comment


      • #4
        wheel cylinder seized ?

        Comment


        • #5
          Are you able to measure the new drums? Just wondering if they're out of true?
          1972 Viva restoration thread - http://www.thecorsa.co.uk/projects-b....html#post1534

          Comment


          • #6
            Wheel cylinder is fine Craig, compressed both pistons with my finger to put a cable tie around it whilst changing the shoes. Have no means of measuring any run-out of the drums unfortunately Taurus.

            Comment


            • #7
              I can only think of two possible causes -there may be others 1) The whole back plate/static brake assembly has been distorted out of true to the rotating drum/ hub. Did you use any force or dismantling that may have changed this relationship?
              2) The exact opposite. The stub axle/bearing/hub assembly is distorted out of true to the back plate components. Did you use any heat on the stub axle , or extreme force when removing the hub nut, or to remove the separated inner race?. Is the stub shaft bent,or the threaded area out of true? Any damage to the face where the bearing thrusts against the back plate, or on the nut, or any washer or thrust bearings that might be used,and are all present? Any signs of excess wear on the stub shaft that might indicate the bearing race has been rotating on its shaft, or any evidence that this has been bodged, such as shimming, filler etc?

              You might be able to detect discrepancies by careful measurement of both axles.
              Last edited by Bugman; 21-10-2015, 02:17 PM.

              Comment


              • #8
                If I read this correctly, you have swapped the rear "hubs" from side to side, and the problem persists on the NS. What do you mean by the "hub"? Do you mean the new drums containing the prefitted bearings, or the stub axles? (sorry, familiar with B setup, not C) Just wondering if prefitted bearings are not in square?

                Comment


                • #9
                  Removed the drum by hand after correctly releasing the handbrake all the way by putting a screwdriver through the hole in the backplate. The only heat I used was on the drum centre to assist in drawing the bearing out whilst on my bench. I even put the old osr drum on the nsr and the problem still exists. The only thing left to change now is the stub axle, but again, no force was used on that apart from undoing the centre bolt, and that wasn't exactly difficult or stubborn to remove.

                  It's an odd one this. Appreciating the suggestion guys, thanks all.

                  Comment


                  • #10
                    I just wonder if the clue is in the fact that ' When I apply the hand brake, the NSR rises and lowers with each revolution of the road wheel'.
                    This would suggest that SOMETHING is eccentric - but why only when the brake is applied?
                    Could it be that the bearing isn't FULLY onto the stub axle? - You could check that approximately the same amount of stub axle thread show OUTSIDE of the nut on both sides.
                    Is it possible that the eccentricity is there at all times, but only noticeable during braking? - Try placing a good solid object (spare wheel?) on the ground close to the NSR, then use this object as a 'steady' to rest a piece of chalk against, spin the wheel and carefully bring the chalk into contact with the rotating tyre/wheel - obviously you would be looking for a (more-or-less) continuous mark.
                    Does there appear to be the same amount of camber on each side? If the stub axle was bent (upwards or downwards) it would affect the camber - Make a rough check with a plumb-line across the face of the road wheel.
                    When you initially removed the brake drum, are you sure that you didn't lever against anything?

                    The above are only thoughts, sorry that I can't offer a definitive answer.

                    Do let us know the eventual outcome.

                    Regards

                    Comment


                    • #11
                      Stub axle I reckon, similar happened to my old b when the bearing seized

                      Comment


                      • #12
                        Well before I shell out on a new stub axle I may just swap the ones around that are on there. Gonna be a few days before i'll have time to do that but i'll let you know the outcome. Before i do that though i'll spin the wheel to see if I can see any obvious run out whilst it's on stands.

                        Comment


                        • #13
                          Wheel run out shouldn't just affect braking, it would be apparent all the time.

                          The rising of the car is down to braking force being applied then disengaged. (Like if you roll forward slowly and engage the handbrake the back of the car will rise due to the rotational force transmitted through the brakes being transferred into lateral force on the suspension.)

                          Just to check that this is apparent with the wheel jacked up and spun by hand, you always get slight variance in resistance but I assume you can feel the inconsistent braking effect just turning the wheel by hand. That proves the effect is being produced within the drum itself and not via any play in something like a suspension bush / shock mounting etc.

                          If so then swapping the stub (maybe source one from a scrappies) is the next step.
                          1972 Viva restoration thread - http://www.thecorsa.co.uk/projects-b....html#post1534

                          Comment


                          • #14
                            Exactly that Taurus, the rising of the car is the brakes biting then not as I said earlier. Tbh I don't think swapping the stub is going to affect anything. If I apply the handbarke a couple of clicks and spin the wheel you can feel the brake intermitently drag as the wheel spins, so everything about it tells me the drum is out of true, but why the hell was it fine before I cleaned everything up, and is now vibrating with the new, and used previously good parts??? Loving the Viva btw, my old man had one - RBO 628H. Burnt the back of my legs when I jumped in it once on the red hot vinyl seats as a kid wearing shorts

                            Comment


                            • #15
                              If the same drum and bearing runs true on one side but not the other doesnt this eliminate it as the cause? What happens if you swop sides with the new ones? When spinning the wheels also check for eccentricity between drum and back plate and compare with the other side. Personally I would just replace the stub axle and see how it goes. The corsa c stub looks quite spindly compared to a corsa B (the only type I have ever changed -on a nova.)As its the nearside it may have been slightly bent in the past by a curbing or something .Your old shoes may have adapted to this by wearing unevenly. When you disturbed the shoes they might no longer have quite matched,and nor do the new ones.
                              Last edited by Bugman; 22-10-2015, 10:46 AM.

                              Comment

                              Working...
                              X