Well this seems very odd to me, but I cannot find a specification for the lateral or radial disc run out on my F-150!

The Chilton manual says to measure the run out and if it's out of spec replace the rotor. The Ford service manual does not seem to give the spec anywhere that I can find. I was all through Section 206, and, unless I'm missing something, I'm just not seeing it.

Can anyone tell me what the specifications should be?

I know a lot of people will just say to replace the rotors, but all I am doing is checking them as part of general maintenance. For now I just need to know the numbers to know whether they should be replaced or not.

PS: I did a forum search and I can't find this topic anywhere. I would think that this might have been discussed somewhere but I couldn't find that either. if it matters, my truck is a 2015 XLT with electronic parking and the 2.7 l engine. 4WD and 17" wheels.

 

if you don't feel and shuddering/pulsing or similar issues when breaking then the runout is fine, when the pads wear out replace the rotors so they are matched to the new pads. I prefer to replace them this way, some will do just pads but rotors do not have any extra material like they did 40 years ago, you basically run them until they wear out and then replace.

 

There's a thickness service limit stamped into the rotors telling me exactly what that should be. Useful if you do machine them.Of course, the Ford service manual says that they should only be turned with an on-vehicle lathe, so not something I'm likely to encounter.

You're right as far as replacing them goes. However if I get to the point where I have shuddering then I've probably passed the service limit and I'd like to know how close I am to it. Still hoping someone knows what the number is.

 

That's the expensive way to do it. A brake job needn't include replacing rotors every time. Unless they're deeply scored, they usually have enough material to turn them once before replacing. Or if the surface is in good condition on both sides and still within specs, just keep them and don't do anything to them.