I replaced the rear brake shoes on my 97 Accord today, and looking at the drums they looked ok and the maximum diameter is listed as 121 centimeters.

Measuring the drums diameter with just a ruler, they look to be about 120 CM.

Does anyone know at what diameter you should replace them, or just wait until 121 CM?

Also was wondering what new drum diameters are brand new.

Thanks for any info!

 

120cm? That's about 47 inches.

Probably next time you replace the shoes, the drums will be worn enough that you want to replace them. That maximum diameter means a shop isn't supposed to re-surface them unless they can do it within that dimension.

I don't know what diameter they are new. Maybe that's in the specs in your owners manual. It'll definitely be in the specs of a Helm repair manual.

 

my mistake, 121 milimeters is the number which is about 4.75 inches in diameter.

I'll check the manual I have and might go to the autoparts store and actually measure a new one to compare.

 

There should be a number that you can safely cut the drum to and a throw away one. Any place that cuts drums should have the specs.

 

I wouldn't bother measuring a new one until next time you have to BUY a new one. The shop that resurfaces them will ask you make/model/year so they can look up the allowable resurfacing dimension. If it's too big, they're supposed to refuse to do it. That's how you'll know you need to buy new ones.