GM-GMC: Brakes, ac delco, brake drums

Mysterious Brake Drum
Mysterious Brake Drum  
QUESTION: Hi! Would you Please tell me the difference in brake drums manufactured by Brenlo ,Bendix ,Wearever and any other manufacturer that manufactures 13" brake drums for a 14 bolt 10.5 ring gear.I am trying to get a reasonable quality set and many people say don't buy these(Not referring to mfg.'s listed above) because they are a very low grade metal.Everyone seems to have a opinion that some are better then others so I would like to ask you about your expertise on this.Where are the drums manufactured.What kind of steel.Heat Ratings etc.Also - How could this happen to a brake drum ? Image attached.Thank You Very Much!!! for any information you can provide.
Never bounced a curb or ran anything over - How could this happen ? (Image attached)

ANSWER: From what I can see from the picture, that material has been removed for balancing purposes.  It is pretty standard practice for all rotor and drum manufacturers to do this.  As for the heat ratings etc I cannot answer that with any certainty.  I work at a GM dealer, so the parts that we install are either genuine GM or AC delco.  I have heard similar complaints, more for rotors than drums though.  For one manufacturer to have a retail price three or four times less than another there must be some corners cut somewhere, the composition of the steel must be comprimised, but this is only a suspision I have no concrete evidence to support it.  If you are looking for a decent quality go with set of AC Delco Drums, they won't be the cheapest available but are of good quality.
Hope this helps.

---------- FOLLOW-UP ----------

QUESTION: Hi! I have looked at Brake Drums all over. I have been purchasing Brake Drums for my vehicles for over 20 years. NEVER!!!! Have I seen a Brake Drum so called "Balanced" as you are refering to here! When you buy a set of Brake Drums - the edges are always perfect.I have contacted auto parts stores and other mechanics - I do not know of any Manufacturer - including General Motors - that would give someone a Brake Drum like this.So I have to say I do not agree with your expert opinion on this.This is "NOT" standard practice and I believe - what it will do - is throw the balance out of the rear bearing and cause the rear bearing and seal to leak - giving a Mechanic another job to repair. Something that should have been prevented that will cause damage to the rear bearings,seal or the rear differential and axle.As I mentioned - I have looked at Brake Drums everywhere - This is "NOT NORMAL" and I believe it is a attempt to throw the balance out on a rear differential and rear wheel bearings and seal.Something that is a costly repair!!!!! I just looked at a Brake Drum in a auto parts store - No Way!!!!! are they like this! I believe I will go with Bendix as the rear Backer Plates are Bendix.A inexperienced mechanic does not know to look for a Bendix Total Brake System and will put inferior Brake Components on a Bendix System.A total Bendix system should remain a total Bendix system.Thank You!!! for your answer - but I must disagree with it.My limited knowledge is enough to recognize that a unqualified mechanic put some sort of after market components - When they should have been replaced with "ORIGINAL BENDIX" parts.Anyhow!!! - Have a Merry Christmas & Happy New Year!!! and Thank You Very Much!!! for taking the time to answer my question to the best of your knowledge.B.

Thank you for that.  Take the drum and put it on a standard wheel balancer and spin it up if you are concerned about it being out of balance.  

"- giving a Mechanic another job to repair......and I believe it is a attempt to throw the balance out on a rear differential and rear wheel bearings and seal.Something that is a costly repair!!!!!"

You should try to have a more positive outlook on things.  Not every mechanic out there is trying to screw their customers.  If you think yours is, than find another that you trust or ask around to find a reputable one.  
Hope that helps.