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curt
08-01-2006, 09:52 PM
I just took off a rear brake drum on my 1955 President,Dana rear end. The nut that calls for 180-200 ft pounds, well this one was not over 80 ft lbs, the durm came off like a dream. What harm is done long term using such low torque? What torque do you fellows use on that nut holding the rear brake drum?[?][?]:)

ROADRACELARK
08-01-2006, 10:54 PM
With that nut loose, you'll wear out the "key" and the "keyway" in the hub:(. You need to inspect it closely for the edges of the key or key way to be worn or rounded over...if they are, replacement is nessessary. Make sure the axel stub and the hub are clean of all grease.... bone dry reassemble and torque to 175 lbs.ft. if the cotter key lines up, great, if not go to the next hole. Hope this helps.:)
Dan

Road Racers turn left AND right.

N8N
08-02-2006, 11:49 AM
Yup, what he said. The high torque is necessary because the hub/axle interface relies on the friction between the axle and the hub along the taper to transmit torque. If the nut is loose enough, during a hard launch or hard braking the load will be transmitted through the key, which is Not Good. the key is only there to locate the hub on the axle and provide "limp home" capability; it is not to be relied on for normal transmission of torque.

nate

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55 Commander Starlight
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curt
08-04-2006, 08:10 PM
The key had a shiney area, edges still look sharo in the key hole, I ordered two new keys. Thanks for tjhe help!!:):)

ROADRACELARK
08-05-2006, 11:29 AM
Curt,
If you haven't already checked the axle bearing grease (this is commonly and area never checked, shop manual recomends repack at 25K mile intervals, IIRC)as well as rear axle grease seals, (inner & outer) now would be the ideal time. Re-pack and/or replace as nessessary. Shop manual gives excellent detailed instructions on these procedures.
Remember when reassembling, make sure you clean all mating surfaces with brake cleaner or the like, assemble totaly dry, set the keyway on the axle at 12o'clock, insert the key, tapered side DOWN and toward the diff, then slide the drum on. With a punch or a drift, tap the key in until it is FLUSH with the outside end of the hub, NO MORE. Install flat washer and nut, torque to 175 ft.lbs. or to the next hole beyond if the cotter pin slot didn't line up at 175. Hope this helps.
Dan

Road Racers turn left AND right.