Split/crack around new drums?

icetech

Well-Known Member
Local time
10:43 AM
Joined
Jun 2, 2022
Messages
350
Reaction score
287
Location
Detroit
So, bought new drums so i can get my rear end back together (Waiting on 1 seal!) Anyway.. the drums showed up and both have this split in them, i have seen pics of other brands with the same thing.. is this just a processing thing? I haven't worked on any drum brakes in over 20 years but i don't recall seeing this before..
P.S. these are raybestos.. (The line where the hub meets the outer ring..
1669824250391.png
 

Cranky

Banned Henchman #27
Staff member
FBBO Gold Member
Local time
9:43 AM
Joined
Dec 4, 2009
Messages
28,985
Reaction score
30,575
Location
Down southeast Taxas
Seen that lots of times and never had a problem with them.
 

icetech

Well-Known Member
Local time
10:43 AM
Joined
Jun 2, 2022
Messages
350
Reaction score
287
Location
Detroit
Like on the left there.. i'm sure it's just the manufacturing.. but just seems odd to me is all, rather check and be sure that's normal :)
IMG_20221130_110914.jpg
 

zyzzyx

FBBO Gold Member
FBBO Gold Member
Local time
9:43 AM
Joined
Aug 5, 2011
Messages
3,188
Reaction score
4,194
Location
Lisle, Illinois
the hub is steel, the drum is cast iron. Two piece, different materials. Probably the way it's manufactured.
Raybestos drums I believe are made of "Chinesium".
 

Cranky

Banned Henchman #27
Staff member
FBBO Gold Member
Local time
9:43 AM
Joined
Dec 4, 2009
Messages
28,985
Reaction score
30,575
Location
Down southeast Taxas
the hub is steel, the drum is cast iron. Two piece, different materials. Probably the way it's manufactured.
Raybestos drums I believe are made of "Chinesium".
What isn't Shinese these days :(
 

icetech

Well-Known Member
Local time
10:43 AM
Joined
Jun 2, 2022
Messages
350
Reaction score
287
Location
Detroit
the hub is steel, the drum is cast iron. Two piece, different materials. Probably the way it's manufactured.
Raybestos drums I believe are made of "Chinesium".

But.. the 2 materials would explain it.. I know it was a silly question but i am paranoid bout brakes.
 

69Bee

FBBO Gold Member
FBBO Gold Member
Local time
8:43 AM
Joined
Nov 17, 2009
Messages
3,971
Reaction score
3,732
Location
Whetstone, AZ
Those are called "Composite" drums. They are a two-piece construction, cast iron outer molded onto a steel hub. What you see is normal.

edit: zyzzyx beat me to it... :thumbsup:
 

RJRENTON

FBBO Gold Member
FBBO Gold Member
Local time
9:43 AM
Joined
Jul 1, 2015
Messages
3,252
Reaction score
3,415
Location
South Shores area of Decatur, Illinois
But.. the 2 materials would explain it.. I know it was a silly question but i am paranoid bout brakes.
Its likely due to the shrinkage rate of the iron casting around the steel flange insert. Iron has many different alloys, and all have different shrinkage rates....possibly cured by a annealing process (controlled cooling to prevent shrinkage cracking as shown). The unknown quantity is the grade or composition of the iron alloy...knowing the source (Chinese) of the iron, it could be old coat hangers or engine blocks or scrap Yugo's or ???? and the casting process....via a mold or centrifugally cast..... judt my opinion of course
BOB RENTON
 

icetech

Well-Known Member
Local time
10:43 AM
Joined
Jun 2, 2022
Messages
350
Reaction score
287
Location
Detroit
Thanks guys, i had no idea they were made of 2 materials... now i know :)
 
Top