Brake Drum Removal

[Guest]

Hello folks. I'm in need of some training on removing keyed brake drums. One of my issues is that I'm not sure what type of key is used for this application--parrallel, taper, etc. If it's parallel, I can see tapping it through, but a taper key seems to be more appropriate for the application and will also be the most challenging to remove. Do I tackle removing the hub/drum with a puller with the key in place, or am I doing myself a disservice by doing that?<P>Thank you for your assistance.

[ply33]

You don't say what kind of car you are working on. On all the older MoPars that I know of the key is square. You remove the drum with a drum puller then remove the key.<P>Even with a puller the drums can sometimes be a pain to get off. Without a proper puller you are very likely to damage the hub/drum and/or axle.

[Guest]

Thanks for the input Ply33. I'm working on a '29 Studebaker Dictator.

[Guest stude8]

The woodruff keys are usuall rectangular in profile shape not square plus if they are for the taper axle they will have an angle cut away on the inside edge that faces the axle.<BR>You didn't say whether this is a wire wheel or wood wheel car?<BR>Wire wheel drums you pull on three of the lug studs with a good tool like Owatonna makes with the arms that extend from a pulling ring with the threaded king bolt and then when it is loaded tight you whack the bolt head to shock the drum into submission. Usually a bit of heat on the hub helps, even if it is only from a propane torch if you don't have acetylene available.<BR>If it is a wood wheel drum they usually have a threaded outside diameter on the hub that you thread a puller tool onto then you run the threaded king bolt up to the axle end and go through the same whack it with heat trick to shock the drum loose. The wood wheel tools are pretty rare to find, a good one would have a split with a pinch bolt that really grips the hub tight when you pull on it. The answer to your original question is yes, you pull the drum with the key in place, it usually comes off with the drum. You might have to clean it up with fine sand paper to get it to fit smoothly again. They sometimes develop a "Wear Pattern" and end up a bit "Offset" from the drum moving on the hub. Good luck with your Dictator, I jusr did brakes on my 1930 President and be sure to use two grades of lining on primary and secondary shoes. The 3 shoe Bendix system on the President requires harder lining on the secondary self activating shoes or they will grab when applied. I had to do the job twice because of that problem. Antigo Auto Parts in Antigo, Wisconsin does good work reasonable for relining old shoes. Stude8

[1913Moline]

A couple of tips from my experience pulling drums on Pierce cars. The tapered axles are about 2 1/2 inch diameter!!! When you use a puller on the hub, dont do anything more than snug it up and then whack the axle with a brass drift or brass hammer sharply. If you pull it up too tight, they seem to pinch tighter on the outer portion of the taper.<P>If you are using heat on a drum with a keyway, only heat the section directly above the keyslot. That is the thinnest section and if you can localize the heat there, you will get the most expansion on the diameter that you are trying to relieve. This heating trick has worked on lots of bound shafts and parts. If you just pour heat to the whole area, everything will expand and you may not accomplish what you want.<P>Good Luck,<P>greg

[Peter J.Heizmann]

Good point Greg.<P>I compare the heat you place on the keyway to welding a Fe casting. Too much heat may free up the hub, BUT, you may damage the integrity of the hub by chrystallizing the carbides in the piece. One thing you don't want to create is weak sections on the piece, then, wonder why it shattered/cracked later. <P>Be very careful so as not to damage the hub's life. Heat it up slightly, if it does not pull, heat it up GRADUALLY until it is free.<P>Regards, Peter J.

[Guest stude8]

The theory of using heat is to cause an expansion great enough to dislodge the bond between the hub and axle. I suppose as an alternative to heating the drum, one could chill the axle (Shrink it even an infinitismal amount) with "Dry Ice" or a CO2 fire extinguisher. If you have access to liquid Helium or other Cryogenic matter even better! I recall accounts where frozen brake drums were freed by backing off the retaining nut a few turns, replacing the cotter key and then driving the car on a rough road with hard stops and starts until the drum loosened by "Natural" forces. Stude8

[ply33]

I guess that, in theory you can heat the hub or chill the axle. But how you are going to chill the axle without also chilling the hub? If you chill both then you will not have released the hub...<P>Having accidentally performed the experiment, I can assure you that leaving off the cotter pin on a rear axle hub nut is not a good idea. So I can believe that loosening the axle nut and driving the car around may will loosen the hub. Having experiened that once through stupidity, I must say that I'd rather get the hub off with a puller.

[Peter J.Heizmann]

Hi, folks.<P>I must add that chilling a Fe part is rapid. For example, Ductile Iron (which is basically a mild steel, pearlitic flakes) can, and, has been known to fail in industrial castings when the temperature falls below -5 F.<P>Hubs are not ductile, thus, being Graphitic (flakes), is more brittle.<P>To heat gradually the hub section and axle section is a lot more gentle to the longevitiy of the part than chryogenic means.<P>My advise, for what it is worth, is remember thermal shock whatever you do with Ferrous parts. Chilling the part rapidly could cause more damage than super heating rapidly. Cryogenically I have no experience, however, I would think one would have more control with heat. Freezing is a rapid shot with little, if any, control of the project.<P>Regards, Peter J.<p>[ 07-24-2002: Message edited by: Peter J Heizmann ]