Alright, here's a terminology lesson for all of you. I brought my G35 Coupe 04' to the shop. It's a 5AT, and many of you will know. the brakes wears out after 15000Km (darn!). So the shop owner told me he needs to machine my rotor if I don't want to change the whole thing.

So.. does machining a rotor = turning a rotor = cutting a rotor?? I have been reading posts using different terms.

Are these procedures refer to the same procedure, grinding a thin layer off the rotor surface? And why is this needed?

04' G35 Coupe's 5AT 's rotor are very thin so I can only machine it once, is this true as well?DOMO

Regards,

ILuvMyG35

 

Also, I brought a digital electronic caliper (measure to 0.0001" accuracy) from CanTire to measure how much I still have left on my front rotors.

How do I measure it correctly? What is the specs on the front and rear rotor. I am suspecting the shop just wanna make money off me by telling me rotor's no good.

 

Most rotors will have the minimum thickness that the manufacture recommends stamped on the rotor, look on the hat area somewhere, or even the edge of the rotor for marks. I seem to remember seeing groove marks in the sides of the brembo rotors when I took them off, I believe this was the manufactures way of identifying minimum thickness (may be wrong). If its not, call infiniti and ask. I didn't have an issue with getting them turned so I wasn't too concerned about it.

Either way, just take several measurements around the rotor to determine it thickness and it will give you a guesstimate at how much they will need to remove. Typically you won't get a shop to remove material if they need to go below that minimum measurement (they are too concerned of being sued if something were to go bad due to the rotor thickness). It really depends on how bad of shape its in on how much material needs to come off to make it true again.

Anyway, GL.

 

I heard that they can be turned on the car. True?

 

I've never seen it done, but I suppose it you had the right equipment it could be done.

 

Yes all those terms do mean the same thing and often used interchangeably. I wouldn't say the oem rotors are thin, but rather the pads are quite abrasive. Chances are it has already eaten away enough rotor mater for 1 resurface by the time you need such a job necessary.

Btw, are you familiar with the Infiniti brake TSB warranty for '03-'04 non brembo G35 owners?
Seeing as you have an 2004 model, you may have just missed the 3 yr/36,000 miles limit, to which Infiniti will pay in full for all services required to replace or rework your pads and rotors.

 

With the trend of ever increasing oem rotor sizes, most all manufactures now recommend (some actually requires) their dealers to only use "on-car" lathe for resurfacing brake rotors. It is the best and surest way to minimize rotor lateral run-outs, the source of brake shimmy.

 

There are several reasons why rotors needs to be turned:

1 - they are warped

2 - there are hot spots throughout the rotor (glazing), and those need to be turned out, otherwise the next brake job wont last and you'll get lots of squealing.

3 - rotors can just be turned because of brake squeeling...whenthe surface hazes, it will make noise and cause excessive heat as well.

Be careful with some shops though. Make sure they tell you what the minimum thickness is and write down what it is after the turning. The thinner a rotor gets, the hotter they will be as well, and that will affect your braking potential. They should also do what's called a cross hatch on the rotors after being turned. Basically they take a sanding pad to the rotor, while it's turning, and put circular scratchers into it. It helps with initial adhesion and brake pad seasoning.

Typically, there are at least 2 cuts done for a rotor turn. 1 to get the 'bad' metal off and the surface completely flat (no warping), and a final cut to clean the surface properly. Depending on the rotors and your driving, your's could need 2-3 turns before the final cut. AND DON'T FORGET, when they are thinner, they don't work as good, regardless of specs.

If you have Brembo's - I would look at the TSB and get to the dealer. If you don't, you may want to consider a better aftermarket rotor, likely slotted or cross drilled. They will dissipate the hear much better, last longer and allow your pads to work more efficiently. You may also want to consider upgrading the pads as well.

This doesn't have to cost $$thousands$$. the general braking system in these cars is very good, but better pads and rotors make a huge difference. Also, for $100, put some stainless brake lines on at the same time...you'll never have a squishy pedal!

Rick

 

Thanks, ISMSOLUTIONS, what is meant by TSB you mentioned in your post?

Regards,
Brian

 

A TSB is a Tech Service Bulletin - somewhat of a recall, althought those are separate as well. There is/was one forthe Brembo cars - but check with your dealer for the possiblity...you may end up with a free brake job!

 

You have that confused for the non-Brembos and only applies for '3-'04 model years.

 

Sorry, my bad..

 

like THX said... machining a rotor,turning a rotor,cutting a rotor are the same.basiclly it's use a turning machine (lathe) to cut a rotor
this is one of many brake lathe models

and this is one of the "on-car" lathe in action


nomally they use the micrometer to check the rotor thickness.but a electronic calipers will do.bring 2 jaw all the way together and then hit reset button to reset the reading to zero.then measure the rotor in different places using the same presure and just read the read out.most digital calipers comes with a button to switch from inches to metric...because i think specs are in metric (mm)

 

How much does it usually cost to turn the rotor? I can get the new ones (OEM from Tony@Riverside) for about $65.

I'm thinking of OEM pads.... the only question I have is it worth turning? My local mechanic suggests that i get new ones.... but he wasn't resoning or making sense when he tried to explain.

 

If you take the rotors to Pep Boys, they will turn them for $6 each, assuming they aren't too thin.