Spec on turning Stepdown front drums

pseftoncomcastnetpseftoncomcastnet Posts: 134Senior Contributor
I've searched the ,manuals, but does anyone have a numerical maximum for turning front drums on a 1951 Commodore? Mine are already .060 over and out-of-round.

Peter Sefton

Comments

  • FrankvintagefullflowcomFrankvintagefullflowcom Posts: 929Senior Contributor

    IMO, if they aren't badly scored and already at +.060, you could remove just enough to make 'em round again. That, of course, depends on how far you need to go to achieve a round drum. Are they round but non-concentric or egg-shaped?

    In any case, if you true them up, don't go any further than you must. Leaving a little "witness" in the scored areas won't affect braking much, if at all, and shows that you didn't take any more than necessary.

    A drum at +.060 will require that the shoes be properly "arced" before installation (assuming that you are relining the shoes). Failing to do so will result in very poor brake performance even though you have new components. Finding a shop (unless you are equipped to do it yourself) is a bit of a  challenge these days. Finding a kid who even knows what a drum is might even be a challenge.  

    I never said any of this and you must eat it after reading it.

    Frank

  • Ken U-TxKen U-Tx Posts: 3,650Senior Contributor
    edited November 2016
    I have heard from other longtime HEt'ers that you may get away with up to .090" over on the Stepdown drums. Paul Schuster is one that comes to mind saying this. I prefer to just find better drums. With all the parts cars out there, there should be some drums well under the .060" recommended max oversize. I agree with arcing the shoes to match the drum at each wheel. I even arced a set of shoes myself,  not too hard to get it reasonably close by fitting to drum and checking with feeler gauges. In my case the shoe's arcs were bigger than the drum by a few thousands:in other words the top and bottom ends of the shoes lining were contacting the drum but there was @ 0.010" gap in center.  When installing new or relined shoes, you often have to recenter the shoes by the major anchor pin adjustment, again this can be done by checking with feeler gauges inserted through the inspection slot on side of the drum. If you do sand or grind on the shoe linings to arc them, DO use proper respiratory protection ( toxic dust mask) such as this: https://www.amazon.com/Safety-Works-817663-Multi-Purpose-Respirator/dp/B00009363G/ref=sr_1_3?ie=UTF8&qid=1478747765&sr=8-3&keywords=asbestos+face+mask

    It is best to do an sanding or grinding outside of the garage/ shop, Especially if garage is attached to house.
    Do not use compressed air, spray can brake cleaner or a vacuum to remove the brake dust, but instead use a mister type spray bottle of water and cleaner such as Simple Green and paper towels to clean and wipe the drums etc.  On any car, you should assume the brake and clutch linings along with various gaskets, etc have asbestos in them. Contrary to what many say, asbestos HAS NOT been completely banned from use in automotive applications.

    I also use the same standard disclaimer as Frank:
    "I never said any of this and you must eat it after reading it."
  • FrankvintagefullflowcomFrankvintagefullflowcom Posts: 929Senior Contributor
    edited November 2016

    I don't believe you'll find any linings made with the "A" word except in cases where one stumbles across some NOS or old relined shoes. True, if you don't know the history of your "new" shoes, best to be cautious. If occasional, inadvertent exposure was deadly, I wouldn't be here to write this......may I'm not............

    Eat this one too. Call it "dessert".

    F

  • pseftoncomcastnetpseftoncomcastnet Posts: 134Senior Contributor
    thanks all, these are great suggestions'

    peter s.
  • supersixsupersix Posts: 38Member
    There is a place in , Los Angles I believe that will put a new drum into your outer drum / hub . I’ll try to fine them but google a little and maybe you can find them. Get new stock drums .....mmmmm
  • supersixsupersix Posts: 38Member
    Here ya go 
    76068678-2BCA-4EBF-B7EC-55DA86206DA7.png
    2048 x 1536 - 895K
  • Ken U-TxKen U-Tx Posts: 3,650Senior Contributor
    Those cast iron liners are for the finned aluminum drums like used on BUICKS, they do not press liners into the thin cast iron drums. There are still many good drums from Hudson parts cars out there.

  • 54coupe54coupe Posts: 137Member
    supersix said:
    Here ya go 
    I called and spoke to this company a couple of months ago. They told me they can recondition Hudson drums. The cost was something like $300.00 each. I figured that for $1200 plus shipping , I could just go with four wheel disc brakes, and get it over with.
  • 54coupe54coupe Posts: 137Member
    54coupe said:
    supersix said:
    Here ya go 
    I called and spoke to this company a couple of months ago. They told me they can recondition Hudson drums. The cost was something like $300.00 each. I figured that for $1200 plus shipping , I could just go with four wheel disc brakes, and get it over with.
    I found my notes... 350 each for the fronts, and 300 for the rears on a 54 Hornet. Plus shipping each way. 
  • Ken U-TxKen U-Tx Posts: 3,650Senior Contributor
    You can still find good Hudson drums in the 11.010" range for like $50-75  a drum.....if you are a club member.

  • supersixsupersix Posts: 38Member
    I’m installing a disc brake set up from Scarebird. You might want to check them out. 125 for the brackets. Rotors, loaded calipers, hoses , were slightly less than 200.00 you have to remove the hubs from the drums and machine a small shoulder off of the hub and enlarge the hole in the rotor about 5 thousandth. New bearings and seals were 180. This set up allows a stock master cylinder to be used although a proportioning valve may be necessary for the rears. 
  • supersixsupersix Posts: 38Member
    Here is a pic of what needs to be done to the hub. Took longer to chuck ‘em up than to turn ‘em down.
    97B870BE-F0A5-4737-821F-032651DC0187.png
    2048 x 1536 - 6M
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