Brakes

Hi y’all.
I took my drums in to be turned yesterday, and at 50k I’m 4mm under the max diameter.
My truck had 39k and new brakes when I bought it from Toyota.

Is this common?

 

Ummmmm is their measuring device still in spec or the monkey behind the tool using and reading it correctly. There is a down and dirty way to check but it isn't always 100% to the spec. On rotors and drums there is a small chamfer before the contact point of the pads/shoes if that chamfer is pretty big and you don't have a whole lot of lip from the braking surface to the chamfer then you should be good to go. In my experience this is not normal and they weren't measuring, reading, or looking at the wrong truck specs when they checked. Take it somewhere else. Also the drum should have the max spec cast into it usually on the inside lip. It will more than likely be in mm but a unit converter on your phone is an invaluable app to convert to sae if that is what they are measuring in.

 

Typically the rear drums last 150k

 

I believe the max was 356 mm and they were at 352 mm.

 

That's very weird is that the max machine to spec or discard spec? I would take it to another shop and see what they say.

 

. It was 4 mm under this number.

 

Forgot I’d taken this picture.

 

Do you have an outside mic. that can measure that distance?

 

The guy at O’reilly’s did. I don’t.

 

Toyota recommended O’reilly’s because their equipment was much better than what Toyota had.

 

have an '05 here......157K miles & rear brakes still going strong

 

Damn, look at that rust. Is that typical for a 5yr old truck?

 

I was surprised by how small this beveled area was when I seen it. Is that the camfer that you’re referring to?

 

Midwest salt working it’s magic.

 

Your drums are still good. As long as your measured numger is less than that spec stamped into the drum you are good. The guy that measured it got confused. Rotors have a minimum spec and drums have a maximum spec. But I would still get some else to measure them.

 

Correct me if I'm wrong but max diameter (O.D.) is 256mm and you're at 252mm. So you're under the max and you should be good. As the drums wear down your current measurement will increase and eventually be over the 256mm max.

 

That number isn’t for the maximum inside width? They would’ve removed more than 4 mm.

 

No, only the inside diameter of the drum changes with wear. As stated above it would be different if we were talking about the front rotors

 

Also, to give you an idea 256mm equals about 10 inches. That would be a very wide drum

 

Yes you are correct! You only have ~.15" to machine before max. dia. which is not a whole lot to get a uniform surface. Yes that chamfer is what I was talking about. I am surprised that you are at that point already. If you cannot go to another shop and get another measurement the drums shouldn't be that expensive I'd just replace them.