Brake Rotor Machining Specs

Brake rotor specs for machining all performance brake rotors are sold in pairs and come zinc coated in either black or silver to help prevent rusting.

Brake rotor machining specs.

The footnote 3 on this bmw denotes the rotor should be replaced not machined. It s a little known fact that you should machine new rotors or drums before installing them on your vehicle. To measure parallelism subtract the smallest value measured from the largest amount measured. As the rotor reaches its minimum thickness the braking distance increases sometimes up to 4 meters.

The only true throwaway rotors are marked like the one in figures 19 2 19 3. Using an on the car lathe can help to reduce runout on new rotors. The assumption is that if the pads are replaced and the rotors are over machine to they should not experience enough wear to allow them to go below discard thickness through the life of that set of pads. It has often been said that you should never machine new rotors but in some cases a new rotor should be machined to match the vehicle with an on the car brake lathe.

A better option would be to remove your brake disc take it to a shop that turns rotors have it turned to the right levels and specs then re install it. Brake rotor machining comes with benefits and disadvantages. Brake rotors should be replaced before they reach the worn rotor minimum thickness limit which. If the parallelism is higher than 0 0006 inches 0 015mm use an approved on car brake lathe and machine the brake rotor.

Check with any rotor or drum manufacture and they recommend this practice. Pads and rotors wear with use so you should keep a close eye on them. One last note on machining. The average difference between nominal and machine to thickness is 050 to 060.

It can also smooth out surface irregularities that can cause vibrations such as varying thickness. What if the runout exceeds the manufacturer s specifications when the new rotor is installed on the vehicle. With the average machining taking off 010 to 015 there is usually always room for one machining and sometimes 2. True throwaway rotors are marked in this fashion.

Brake pads should be replaced when there is 1 8 to 3 16 of friction material left on the steel backing plate. If the rotor thickness is acceptable a dial indicator should be used to check for lateral run out dishing or taper see figure 2. Disc brake rotor minimum thickness also known as scrap thickness is the minimum safe working thickness of a rotor at which it must be replaced. So don t think that installing new rotors or drums will solve a vibration problem sometimes it doesn t.

This is a simple machine that can be used to machine a rotor.