The only time I ever replace rotors is if:
1) they can't be turned any more
2) I switched to a ceramic pad and the equipped rotors weren't built to handle it

There's nothing wrong with turning a rotor if it has some life left. It's also pretty normal to see some surface rust on rotors if it's wet / salty outside. I feel like there have been a lot of these discussions in multiple threads lately.

 

Ok so I've removed a few posts that meant this thread was going way off topic.
The subject as penned by the OP is corroded rotors / discs, please stay on topic and help where possible


Thanks

 

Update:
I received an online survey from Jaguar. I responded with my displeasure in having to replace rotors that only had 30,000 miles because they were corroded. Got a call from jaguar north America and went through my story with them. The lady said she would investigate and get back to me within 3 days. She did and they are sending me a $300 customer goodwill certificate that can be used on service or accessories and has no expiration date. I can't complain about that!

 

You've won a watch there buddy, nice one Jaguar

 

Good.

I was about to suggest that if the vehicle was a true CPO under the Jaguar
CPO program, the rotors should never have been passed in the first place.

As for turning rotors ... I believe in it. Light skim cuts.

The problem is finding a shop that will do it that way
and do it right.

Can't see the point of shining up hills and valleys with
sandpaper though. Either its flat or its not.

 

On the other hand, using it to remove pad deposits from an otherwise serviceable rotor makes far more sense than grinding metal away...............

 

It was a CPO. It was my son's leased car that he paid to have the certification inspection and then he purchased the car at the end of the lease a few weeks later. That was the point that I tried to make at the dealer. How could these rotors be so bad but yet passed an inspection a few weeks earlier!

 

If you can remove pad imprinting in this way then you can save money. However, if you can't remove pad imprinting by a series of very hard braking events, the standard method, I very much doubt emery cloth will help. Sanding or grinding the sharp edges of squealing pads can work to eliminate squeal but I don't think sanding badly imprinted rotors could be cost effective from a labour perspective. Depends what you value your time at.

 

Who mentioned emery cloth?

 

I did. It's a type of sandpaper used mainly on metals. Using anything less to sand anything metal is just working up a sweat, it's not removing anything.

Pad imprinting isn't just a surface build up it is actually embedded into the cast iron, that's how brakes bed in. You cannot remove pad imprinting with ordinary sandpaper. I doubt you can make much of an impression with emery cloth but you're welcome to think so.

 

I can only assume that you have little or no actual hands-on experience with such matters then. The 3M kit I mentioned way up above works just great for removing pad deposits that have contaminated the rotor. There's lots of similar products on the market. If your mechanic is not aware of this procedure, that's at least two areas where he's steered you wrong.

 

Aluminum oxide is the abrasive embedded into emery cloth so we are on the same page.

The link says nothing about removing pad imprinting, only scratching the surface of machined discs which is a similar idea to cylinder honing. Good quality new discs are already machined with such a surface.

I am fully familiar with brake servicing which is why I no longer do it myself. The labour isn't paid back by results.

The most effective way to remove pad imprinting is rebedding by successive very hard stops. If that doesn't work the most cost effective repair is new good quality discs.

Here's good information from one of the world's leading brake manufacturers:

http://mintex.co.uk/wp-content/uploa...isc-EN-WEB.pdf