brake disc machine

[Veee1.8t]

hi guys just a quick question, if theres a slight lip on the rotor discs can i get them machined or would yopu have to replace them? asking because the brake place near mine reckons i have to replace the rotors rthat than machine???


cheers guys
vee

[Guy_H]

Its a thickness issue, not a Can / Can not machine issue.

If they can be machined & be over the minimum thickness - thats legal, if they machine them & they are undersize, thats Illegal.

If they measured them & tell you they won't take a machine (and you trust them) - then thats correct. If in doubt - visit a second Brake place & get their opinion!

Good luck

[Bubu]

Where on the disc is the lip?

Its normal wear for them to have a slight lip on the outer and inner most edge of the disc. Thats because the brake pads are just slightly smaller than the disc and therefore do not wear out the entire face of the disc.

[Preen59]

What Guy is saying is that if the discs will not clean up on both sides at minimum thickness after machining them, then you have to replace them. The lip isn't really an issue unless it's fairly thick, in which case your rotors could be getting down to minimum thickness...

[Veee1.8t]

theres a bit of a lip around the edge of the rotor, not much lip on the back rotors. what happens if they are too thin when machined?

[Blitzen]

theres a bit of a lip around the edge of the rotor, not much lip on the back rotors. what happens if they are too thin when machined?

If they are too thin after machining, they will be unroadworthy, and will need to be replaced.

[Spec83]

theres a bit of a lip around the edge of the rotor, not much lip on the back rotors. what happens if they are too thin when machined?

They will be less resistant to temperature fluctuations and develop warping if I rememeber correctly...

[Jmac]

Actually the last post is close to the money, When you go undersize they may look ok and brake in general "ok" and you think what the hell ill use them . Well as the previous post states the thermal efficiency of the brakes. When you are undersize the stopping distance actually increases as the disc doesnt cool as quick. Imo you shouldnt mess with your brakes there is a min thickness stated on the disc and manual for a very good reason. There really isnt much difference between New thickness and min thickness around 2-3mm. So whoever you get to machine your discs should be competent and someone you know and trust that will measure them and be straight up with you. Trying to save you a bit of money might bite you down the track.
My 2c
JMac

[Ben_GTI]

It's a good justification to your wife or gf as to why you need to get a Brembo kit from APR

[Veee1.8t]

thanks guys....im going to get them checked this week....whats the round about price of discs anyway and are there specific brands to look out for?

cheers
vee

[Bubu]

DBA (Disc Brakes Australia) have a very good reputation for making discs from OEM replacements to more heavy duty stuff for the track.

Have a look at their website and see what they got.

https://www.dba.com.au

[Blitzen]

DBA (Disc Brakes Australia) have a very good reputation for making discs from OEM replacements to more heavy duty stuff for the track.

Have a look at their website and see what they got.

www.dba.com.au

When I rang DBA diretly the other week(Brisbane office), they said they only had the direct replacement discs for the 9N Polo, and no slotted, or drilled and slotted items, however they did have the full range of discs for the 6N Polo...Go figure!!

[Veee1.8t]

hey blitzen...would you have the part number for the 9n polo discs..a mate works for repco and tried rining dba for the discs but they said they only have have them for 6n.

cheers mate.
v

[Blitzen]

hey blitzen...would you have the part number for the 9n polo discs..a mate works for repco and tried rining dba for the discs but they said they only have have them for 6n.

cheers mate.
v

Sorry mate...I don't have the part number, as I rang DBA directly to get the part number for slotted rotors, not the plain rotors, so I didn't bother in the end.

[Veee1.8t]

but theres definatley one for the 9n polos?