New brake discs?

[msherry21]

Hi all, Basically as the title really,

I have ordered new Pagid pads all round but was thinking of getting new discs as well. How do I know if I need new discs or not? Is there a check I can do? I'm not that technically minded, sorry.

thanks for any help,

Cheers,

Michael.

[System-G]

Discs can develope a number of faults over time, but basically if there are deep grooves running the circumfrence (sp?) or if there is a "lip" present near the edge of the discs or you feel juddering when braking, it's time to replace discs.

As a rule I always change discs when I do the pads (and/or visa~versa).

[Ian Geary]

Assumming you've not had any shaking or shuddering from the wheel when braking (a usual sign that front discs are warped) the easiest way is a simple visual test, which can be done with the wheel on, but preferably with it off:

is the disc scored? (usually caused by pads that have worn down to metal)
is the disc discoloured? - blueish streaks are a sign of overheating at some point, which can warp discs.

Also, feel the outer edge of the discs - is there a lip? This gives an indicator of how far down the braking surface of the disc has worn (the very outer edge isn't in contact with the pads, so doesn't wear.

If the top three are no, then your discs will probably be OK and won't need changing.

A more thorough way would be to measure the disc thickness, and also it's run out - ie is the disc warped? but you'll need a gauge to measure this.

Mk 2 plain front discs are £25 each for rev1 and £30 for rev2 onwards (plus vat and delivery) from Brakes International. You have to buy 2 at once of course. Rears are £35 and £27 respectively, so not huge money.

I've assummed you've got a Mk2, as the majority of people on here have (no offence mk1 people)

Hope this helps you decide - as you're having the pads off anyway I'd say change them, but it depends what budget you're on.

Don't forget to bed them in for a hundred miles or so.


Ian

[BenF]

Hi all, Basically as the title really,

I have ordered new Pagid pads all round but was thinking of getting new discs as well. How do I know if I need new discs or not? Is there a check I can do? I'm not that technically minded, sorry.

thanks for any help,

Cheers,

Michael.

Just wondering - why do you think you need to change them at the moment?

There are some tests you can do if you've got the right tools (minimum disk thickness, run-out tests to check to see if they're warped) - if you don't have the tools its probably cheaper/easier just to get a new set of Brakes international Disks and put them on to go with the pads.

Btw, only use new pads and new disks together - don't mix old pads and disks.

[JohnnyC]

Btw, only use new pads and new disks together - don't mix old pads and disks.

Nothing wrong with new pads & old discs.

I was originally led to believe you should only change discs at every 2nd pad change.
I guess it depends though, my first car wore out it's pads at 27,000 miles.
Whereas on my wifes car I changed the pads because I also needed to change the discs that had developed a fault - the pads were only 2 thirds worn at 40,000 miles, crazy. If the discs hadn't developed the fault and the pads had lasted 60K miles then I'd not want to keep the discs to 120K miles