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Problem with rear drum brakes, I'm out of ideas.

Discussion in 'Engine and Drivetrain/Mechanical' started by msell66, Jul 19, 2018.

  1. Horseplay

    Horseplay I Don't Care. Do you?

    Yeah, that pretty much sums up his reply right there.
  2. kb3

    kb3 Well-Known Member

    I would be tempted to spray a light coat of paint inside the entire drum and then install it. Should rub the paint off somewhere!?
    Grabber70Mach likes this.
  3. stangg

    stangg Active Member

    It sounds like you've discounted this idea because other "reputable" shops have looked at it.... yet none have come up with an answer.

    You can trust anyone's work, but when issues arise, go ahead and verify... hence why I suggest checking the drums run out... preferably bolted to the same axles. Just bolt the drums on "inside out", and set up a dial indicator to read the turned surface.

    I'd imagine an untrue surface would float some when turning by hand, and become more resistant when bolted down. Since the drums are hub centric, is there any slop between the drum's bore and axle's hub? what about the axle studs, are the splines protruding through the axle flange too much and not clearing the stud holes in the drum?

    By the way, I've seen some brake lathes with a bit of a wobble on their spindles that would obviously translate on to the disc / drums. Perhaps not enough to cause an issue with street pads, but maybe enough to exaggerate the drag with performance pads.
  4. Horseplay

    Horseplay I Don't Care. Do you?

    Not discounting at all. As a matter of fact you're on the same path I have been on with this since the start. Prior to this thread I asked Mark to take his axles over to the guy who built my rear end so they could check them out. And for the record, he has tried two sets of drums and had the first turned and then checked AGAIN to verify they were not out of round, etc. I'm of the mindset now that when torqued down something in the axles, studs, drum is getting, in technical terms, out of whack do to some incorrect contact surface issue. And to answer another question you pose, Mark says the the hub centric hubs fit perfect on the axle hubs.

    I'm done racking my brain from afar. Going to wait and see what this qualified Ford tech says this weekend.
  5. msell66

    msell66 Burning Fossil Fuels at c2 Donator

    I'm going to do this, again.
  6. msell66

    msell66 Burning Fossil Fuels at c2 Donator

    Never fails. Got stood up by the Ford tech

  7. tarafied1

    tarafied1 Well-Known Member

    bummer, I'm curious to know what's up with these things!
    Grabber70Mach and msell66 like this.
  8. Grabber70Mach

    Grabber70Mach Well-Known Member

    I'm with Craig but will add unless he has a good excuse may the fleas of a thousand camels infest his house.
    tarafied1 likes this.
  9. Gas_Pumps

    Gas_Pumps New Member

  10. Gas_Pumps

    Gas_Pumps New Member

    Is the picture the left or right side. Which way is forward? There should be a primary and secondary shoe on each side. The materials can be different. The forward shoe helps the brakes apply and must be the forward shoe. There is a left and right adjuster also. There is an L & R on the inside of the short cap. Did you tighten the adjuster just till you couldn't rotate the wheel or until the adjuster was difficult to turn?
  11. Gas_Pumps

    Gas_Pumps New Member

  12. Gas_Pumps

    Gas_Pumps New Member

    Spring arrangement does not agree with the 66 Ford service manual. Could be different if you bought a kit that included instructions etc.
  13. msell66

    msell66 Burning Fossil Fuels at c2 Donator

    These are not “Ford” brakes. The R4 shoes are the same size as always. Porterfield does not make the shoes different sizes and they worked fine on the old brakes.

    I’ve given up and just adjusted them with the wheels on. I’ll see how they work at the October race.

  14. Mach1Rider

    Mach1Rider Member

    Have you tried to verify the housing ends are square to the center section?
    I had like problem and it came down to the housing ends were bent ever so slightly from previous accident.
    The dragging hub only appeared when the wheels were on tightly.
  15. Mach1Rider

    Mach1Rider Member

    Reading thru this in post 27 you found the problem. The drums are binding on the backing plate.
    Look for the reason this is happening, drum depth to deep or axles set back too far in.
    I saw where the axles have new bearings installed, they may have been set too close to hubs.
  16. msell66

    msell66 Burning Fossil Fuels at c2 Donator

    The drums are not contacting the backing plates. There was no difference before or after bearings were replaced.

  17. Gas_Pumps

    Gas_Pumps New Member

    When there were only drum brakes and before automatic adjusters, I used to adjust then until the adjuster was tight and you could not turn the wheel in the forward direction. Then back it off until the wheel would almost turn freely. That way you were sure the shoes were centered. All done after turning the drums and radiusing the shoes to fit the drum. Nobody radiuses the shoes any more.
  18. JeffTepper

    JeffTepper Well-Known Member

    I was just wondering, have the shoes been arched (radiused) to match the drums?
  19. msell66

    msell66 Burning Fossil Fuels at c2 Donator

    The shoes fit the drum radius. Both sets, the stock type and the R4’s.

  20. msell66

    msell66 Burning Fossil Fuels at c2 Donator

    So, Quick Performance is here in town. They had a set of 11” x 2 1/4” rear drum brakes for the small bearing 9”. I bought the pass side to swap out what I have on the car. Sure enough, the problem is fixed. It’s been the backing plate all along. Now I can adjust the brakes so they just start to drag, mount the wheel and it still turns fine. Bought the driver side today and will swap that out soon.

    Now it all works with the same parts and drums, just the backing plates has changed! They are either bent or where the shoes contact, they’re not even. The drums have never made any contact to the backing plate.


    Grabber70Mach likes this.

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