Tourer - rear disc questions

[fago]

Further to my previous post I bought a 2007 tourer.

One of the issues from the pre purchase check was that one of the rear discs had been replaced.
The Honda dealer recommended both be replaced.
I am just trying to understand the technical aspects of this, as its going to cost a bit.
One rear disc was replaced at about 22K when a stone got caught between the pad and disc and scored it.

So I am trying to understand:
- with one replaced what is the safety issue: can the slight width difference make that much difference in braking distribution.
- when normally would the rear discs need to be replaced.
- why not replace the other since there's just 10K on the new disc.

thanks.

 

[jayok]

So I am trying to understand:
- with one replaced what is the safety issue: can the slight width difference make that much difference in braking distribution.
- when normally would the rear discs need to be replaced.
- why not replace the other since there's just 10K on the new disc.

thanks.

Discs are normally replaced in pairs to maintain a balancing braking force. However, for the rear discs, which don't only about 10% of the braking effort (90% from the front) methinks, there'd be little wear between the two at 10K.

Having said that for the sake of safety, I'd replace both rotors, as brakes are ultimately what will stop you. Rear Rotors aren't that expensive.

I take it you bought it privately? If you bought form a dealer get them to fix it.

<edit> I missed the question about when would you replace them. Normally once they are outside the serivce limit for thickness - no idea what that is without a service manual. I normally do this by checking the amount of lip on the rotor - more of a rule of thumb thingy

 

[brodziu]

<edit> I missed the question about when would you replace them. Normally once they are outside the serivce limit for thickness - no idea what that is without a service manual.

less than 8mm it's scrap.

 

[accord player]

Always check they really need replacing. A notorious dealer trick is to advise punters to replace partially worn discs when theres still good mileage left in them. It gives their workshop revenue & with scrap prices at an all time high the dealer gets cash back from the scrap metal dealer at the end of the month. No one dares to question it cos its safety related. However I must stress that you have to bear in mind that they dont last forever and you need to keep an eye on them and replace when necessary - especially if youre heavy on the brakes.

 

[crolandc]

In my opinion if both discs are okay that's it ! waste of money replacing something that is okay. Just check for lipping on oldest disc, if only slight forget it.

 

[riot68]

I wouldn't bother either, there's going to be so little difference between them, just do what you should be doing anyway and keep on eye on them...