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Brake drum

Posted: Thu Feb 06, 2020 1:41 pm
by egdod
Hi all, can anyone tell me the maximum size the 3/4 tonne-1 1/2 tonne brake drum can safely be skimmed out too?

Re: Brake drum

Posted: Thu Feb 06, 2020 1:56 pm
by Gordon_M
I've never had to do it, but because the outside face is cast and probably not perfectly concentric with the bore I'd be more inclined to look at the section thickness at at least four points round the drum, rather than an internal diameter. It's also likely that you wouldn't want to skim it to take out every single internal mark to full depth, unless you were very lucky.

Re: Brake drum

Posted: Thu Feb 06, 2020 2:04 pm
by egdod
Hi Gordon, I’m not looking to skim as the drum is in nice nick, I’ve run out of adjustment so need to know if the drum is ok to use with oversize linings.

Dave

Re: Brake drum

Posted: Thu Feb 06, 2020 2:14 pm
by Gordon_M
If the drum looks good, just go for it, but try to be the same both sides. :thumbup:

Re: Brake drum

Posted: Thu Feb 06, 2020 2:15 pm
by egdod
Drum looks good but would be nice to know for sure.

Re: Brake drum

Posted: Sat Feb 08, 2020 5:04 pm
by Kaegi
a brand new drum would be 14.125 or slightly less. maximum diameter is 14.215. some books say 14.185 but I have run them at 14.215 with no heat issues and I used to drive them many many 1000s of miles

and always machine drum when its attached to the hub!!

Re: Brake drum

Posted: Sun Feb 09, 2020 12:14 am
by Ray Edsall
G,Day all . My wc53 seems to come to a stop when i take my foot of the accelerator :lol: .If you take your drums to get machined .Tell the machinast that you only want a fraction taken off . Most shops will take every score mark out , There for wasting a lot of metal,and stopping into the future . A few score marks will not matter as the brake shoes will settle down into any groves, that might be in the drum .As new drums are almost extinct ,it is not a good policy to take to much metal off . The drum,s that are on your truck will last a lot longer that way . I seem to recall ,that when the drums get machined past the champher on the edge they are getting to there use by date .Ray

Re: Brake drum

Posted: Sun Feb 09, 2020 1:00 pm
by egdod
Hi, not looking to machine the drums as they are in perfect condition just need the maximum allowable diameter,thanks