brake pedal hammering after new drums fitted

Discussion in 'Mech Tech' started by SeanOC, Jun 7, 2024 at 1:15 PM.

  1. Hi all
    As above I have had new brake drums fitted, but when I break, I get hammering through the pedal. I don’t think it’s The vehicle is juddering just the Break pedal
    It’s like a pulse when braking at slow speeds.
    Any ideas before I start poking things?.

    Further comment.
    I have removed the wheels and drums & found that one shows signs of high temp, but only on one side of the drum. See pics.
    I replaced the drums as the same wheel was getting very hot & smelling.
    As I recall; there have never been any anti-rattle springs on clips on the van. But the mechanic drilled holes in the back plate when he replaced the shoes previously. Could the shoes be out of place?
    Any ideas please @davidoft @Lasty ?

    Attached Files:

    Last edited: Jun 11, 2024 at 2:30 PM
  2. Ordinarily that's a typical warped drum symptom but you have new drums ...
    Did they seat ok and nip up the cross head screws ?

    Sent from my SM-G960F using Tapatalk
    SeanOC likes this.
  3. mikedjames

    mikedjames Supporter

    Did the drums go on fully- torquing the wheel nuts should have helped.

    If its a faster hammering, then a misassembled handbrake lever could be hitting the back of the wheel studs.
    Somebody not closing up the horseshoe clip that secures the pin that holds the handbrake lever to the brake shoe (clip falls off, orbits drum and scratches shoes as it drags between the shoe and drum) , or they have used the wrong length pin to hold the lever on ( too long, lever rocks sideways. ..) .. I have done both.
    Pulling on the handbrake while driving will change the noise if its the lever moving around.

    In any case, wheel off, undo nuts securing drum, remove drum, inspect assembly.
    Last edited: Jun 7, 2024 at 3:22 PM
    SeanOC likes this.
  4. Does sound like warped drums.
    SeanOC likes this.
  5. davidoft

    davidoft Sponsor

    Sometimes you have to centre drums, pull the wheel off, rotate drum1/4 of a turn, press brake , do it a few times
    PanZer, SeanOC and Lasty like this.
  6. Do you have to shake it all about?
    davidoft likes this.
  7. davidoft

    davidoft Sponsor

    most definitely :D
    snotty likes this.
  8. That's what it's all about.
    snotty likes this.
  9. He forgot to put his left arm in :rolleyes:
  10. If the pins are the cause it is weird that the hot-spot is only on one part of the drum & it didn't smell or seem any hotter than the other side when I checked after driving for 30 miles...
  11. I guess I could just remove the anti-rattle pins & see if the vibration goes away ?
  12. Removed anti-rattle pins as SAMBA says they are not needed on a 1977 bay. - No improvement.
    I centered the drums as per @davidoft suggestion. - No improvement.
    How do I check for a warped drum?
  13. davidoft

    davidoft Sponsor


    The originals back on
  14. ^this
    davidoft likes this.
  15. mikedjames

    mikedjames Supporter

    Tighten the adjusters or pull on the handbrake until it just binds. Rotate the wheel 360 degrees. If the drag increases or decreases in sync with the rotation its either warped drum or the axle stub is bent..

    When mine warped, you couldnt turn it past the warped in point ( drums turning elliptical, probably got too hot then stopped with the handbrake on) , which happened twice per rotation of the wheel.. so I put the old drums back until the edge of the drum started rusting away after another 5 or so years.

    The anti rattle clips do nothing much (except making putting the shoes on harder ) which is why they were deleted.
    Last edited: Jun 11, 2024 at 6:11 PM
  16. Jack one wheel up, chock the other wheel. Remove wheel and refit and nip up the wheel nuts. Start the engine, release the handbrake, put in second gear release the clutch the drum will turn and note if there is any runout. This was a new pair of Febi drums. Don't do this if you have a limited slip differential.
    Lasty likes this.
  17. Stick with the original stuff!

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