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1976 3/4 ton 4wd drum brakes

Discussion in 'Chevy Trucks' started by 3/4tonTodd, Sep 5, 2000.

  1. 3/4tonTodd

    3/4tonTodd Member
    Messages: 63

    First off, I'd like to thank Chuck for his pages and his advice. I've been emailing him a lot and he's been responding to every one of my questions. I felt like I was taking up too much of his time, so I came here to give him a break from my brakes. My problem is this - I can't get the brake drum off of the truck. I adjusted them all the way down, pulled the axle shaft (full floater 14 bolt GM) and I can't get the silly thing off. After pulling the axle shaft, I removed the two large nuts, behind which is a large washer. Behind that last washer is a bearing set, which doesn't seem to come out until the drum is off - but I can't get the drum off. Am I missing a step? I can't find any further info in my Chilton's book, and a big hammer didn't do the trick. Bigger hammer, maybe?
  2. Alan

    Alan PlowSite.com Addict
    Messages: 1,393

    I'll bet there is a ridge around the inner edge of the drum that is holding you up. Back the shoes off all the way if you can taht will help, if you can't adjust them, then get out the prybars and big hammer and be prepared to wreck some hardware taht holds the shoes to the backing plate.
  3. plowking35

    plowking35 2000 Club Member
    from SE CT
    Messages: 2,923

    Better yet remove the backing plates from the housing and remove the drum and plate in one piece. Then use a press to separate the two.
  4. TX_Mudder

    TX_Mudder Junior Member
    Messages: 6

    I'll tell you how I got them off

    I have a 76 k10 that I put on k20 axles. I also changed the rear drums over to discs, so I had to take the drums off and they just wouldn't budge. You said you took the axles out and the hub nuts off, so the drum CAN come off now, it's just doesn't want to. If you promise not to laugh, I'll tell you how I got mine off. I hooked two tie-downs to the lips of the drum (It's secure) and then to the hitch on my 96 Dodge Ram with the 360. I eeeeeeeeeeeeased onto the throttle real slow and pulled the d**m things off.
    Not sure what the neighbors thought about it, but it worked.
    -- Mike

    BTW, the shoes were just wedged into the drum and that's why it wouldn't come off. It didnt damage anything taking it off this way and I could have reused evrything but the shoes if I had kept drum brakes.
    Obviously have the drum pop off onto grass and not your concrete driveway...
  5. bill rogers

    bill rogers Junior Member
    Messages: 6

    I have had good luck getting off pesky brake drums with a slide hammer. You will need one with a 90 degree flange ,put flange on back lip of drum and wang away then move it a few inchs and wang some more, keep going aroun drum untill they pop.
    bill rogers....
  6. grovej

    grovej Junior Member
    Messages: 3

    Hello all
    I just bought a 79 K20 1 month ago. I have been doing the basics. I need to adjust the rear breaks and need some help. I have the 14 bolt rear end, full floater. There is no access on the back of the drum to adjust the shoes. I looked at chucks chevy page and see that the 8 bolts need to be removed to get to the shoes. What precautions do I need to take to get them off, make the adustments and get everything back together. I can get the 8 bolts undone but I dont want to pull anything else out without having the right tools or needed extra parts

    79 K20
    Edelbrock Carb
  7. 75

    75 PlowSite.com Addict
    Messages: 1,382

    Grovej - look on the backing plate for two slots about an inch long on the lower portion (below the axle tube) They may have metal or rubber plugs in them so they won't be obvious at a glance, but those slots are where the brake adjustment is done.

    You need a brake adjusting tool (I've often heard them called "brake spoons") to reach in through the slot and engage the teeth ("star wheel") on the brake self-adjuster - which don't seem to self-adjust that well a lot of the time.

    Now, if it turns out the adjusters are seized, which isn't uncommon, you will need to get into more extensive brake work to replace them: Pulling the hub/drum assembly as described earlier in this thread and then removing the shoes/springs to get the adjusters out. Use plenty of antiseize on the new adjusters when they go together if you wind up replacing yours.
  8. grovej

    grovej Junior Member
    Messages: 3

    Thanks Rob
    I did look at the backing plate a while ago but only saw what looked like slots you could inspect the shoes. There are two slots per backing plate and they are about even with the axle tube. The slots are also about 180 degrees apart from each other. I looked at the bottom of the backing plate and there is no hole or knock out where I think the star wheel is located. I do have a small amount of fluid coming from the drums and when I remove the plugs from the slots it looks like there is fluid on the shoes. I am not sure if it is brake fluid or if I have an oil seal gone. No matter what I think the drums have to come off for inspection.
    Any other suggestions you might have will help

  9. 75

    75 PlowSite.com Addict
    Messages: 1,382

    If the fluid level in the brake reservoir for the rear half of the system is dropping, there's a leak somewhere and it could be the rear cylinder(s). If the brake fluid level stays up, it's axle lube that's leaking. Could also be a combination of the two, either way as you mention it's time to pull the drums and check things out.

    If there is fluid on the shoes I'd replace them, and since everything will be apart it's a good idea to put all new stuff in back there while you are at it: No point in going through all the work again 6 months later to replace another component, especially since it's a bit more work pulling the drum on a full-floater axle as compared a half-ton style.

    Don't forget to put a new axle seal in the hub/drum assembly even if it wasn't leaking when you took it apart - cheap insurance.
  10. Bill c

    Bill c PlowSite.com Veteran
    from ny
    Messages: 85

    Id have to agree with that there is a lip on the inner edge holding the drum on.If the shoes are adjusted in and the drums still won't come off ,I fire up the demo saw and cut a few grooves and then a few whacks with a mini sledge between the cuts and off they come.Don't be afraid to cut the drums they are most likely junk.
  11. CT18fireman

    CT18fireman Banned
    Messages: 2,133

    Hey Rob any progress on your truck? It could be snowing in 5 months.

    Better get moving. Hehe.
  12. grovej

    grovej Junior Member
    Messages: 3

    Thanks Rob
    I will let you know what the out come is. This is not my daily driver so it will be awhile.

  13. 75

    75 PlowSite.com Addict
    Messages: 1,382

    Haven't been too active on the truck the past month or so (been ironing "bugs" out of the Harley) but I have been plugging away at sheet metal work and the driveshafts are all machined up ready to go in.

    You're right - winter might seem a long way off but it sneaks up fast.......................... :eek: