Disc Skimming Opinions

[jamesogt]

My Boxster S has just passed it MOT.

As a note they have mentioned that the 2 front discs are looking corroded/creating wobble under braking. The feel through the pedal is still very minimal even at 70mph.

The car only does circa 5k miles a year and I am guessing this could be the reason for the corrosion build up.

Is it worth having them skimmed for £70 before jumping in to buying and having new discs fitted?

Cheers

[thegoose]

Have you tried the Italian tune-up method yet?

[jamesogt]

thegoose said:

Have you tried the Italian tune-up method yet?

Does that involve going out and possibly finding a long straight road with nobody behind me and testing there emergency stopping at 70?

[Trev450]

jamesogt said:

thegoose said:

Have you tried the Italian tune-up method yet?

Does that involve going out and possibly finding a long straight road with nobody behind me and testing there emergency stopping at 70?

Something along those lines, yes.

The technique to adopt is to bring the car from about 70 to about 20 mph as quickly as possible a number of times. Don't bring it to a complete stand still and cool them down before parking up and applying the handbrake.

[thegoose]

jamesogt said:

Does that involve going out and possibly finding a long straight road with nobody behind me and testing there emergency stopping at 70?

Repeatedly as necessary, but not allowing the brakes to become too over-heated.

You can also drive along, take your feet off all pedals, then press the brake lightly with your left foot, and keep doing so, followed by the accelerator (if done the other way around the eGas will just cut the throttle) - you can then drive along at a more moderate pace whilst also working the brakes quite hard. If you've never done it before I'd suggest doing this on a closed section of straight road as I wouldn't want to be responsible for anyone's (in)ability to operate the brake pedal with their left foot.

[MadMark911]

jamesogt said:

thegoose said:

Have you tried the Italian tune-up method yet?

Does that involve going out and possibly finding a long straight road with nobody behind me and testing there emergency stopping at 70?

5 really hard stops from well over 70 leptons should do it - otherwise it's new discs and pads for you! Perhaps worth passing on that if they're corroded and pitted on the innner / outer disc faces - then they will be "internally" corroded too. Mine failed it's MOT not on disc face corrosion (there wasn't any) - but on "internal, structural corrosion of the discs". In essence the metal inner sections of the disc were so badly rusted that they weren't safe ....

[jamesogt]

Cheers for the replies.

It has passed, it was just in the comments section. I am assuming as it passed they can't be too bad. And like I mention the feel through the pedal is very minimal.

[MadMark911]

James - what I would say is that I bought my Boxster S just before it was 2 years old (at about 16,000 miles) and after I changed the discs and pads (at about 24,000 miles and 3 years old) - it stopped harder than it had ever done!

Amazing feeling of deceleration and less pedal pressure required too - they just "bit" so much harder, so do be aware that as they corrode and the pads age / go through more heat cycles - they lose performance!

[jas xjr]

if at all possible , just drive it more often

[gl20]

MadMark911 said:

James - what I would say is that I bought my Boxster S just before it was 2 years old (at about 16,000 miles) and after I changed the discs and pads (at about 24,000 miles and 3 years old) - it stopped harder than it had ever done!

Amazing feeling of deceleration and less pedal pressure required too - they just "bit" so much harder, so do be aware that as they corrode and the pads age / go through more heat cycles - they lose performance!

Agree with this. The first time I bought a Porsche I hadn't done all my homework so didn't know about this problem and resented the OPC failing it on its first ever MOT (somewhere else passed it, with an advisory note). While annoying, I should have just changed them. On my second Box the brakes were clean and I've kept them this way and the difference is night and day. Now if I'm away for a week and see even a small bit of corrosion on the disc surfaces on my return I take it straight out to burn it off.

[anonymous-user]

gl20 said:

MadMark911 said:

James - what I would say is that I bought my Boxster S just before it was 2 years old (at about 16,000 miles) and after I changed the discs and pads (at about 24,000 miles and 3 years old) - it stopped harder than it had ever done!

Amazing feeling of deceleration and less pedal pressure required too - they just "bit" so much harder, so do be aware that as they corrode and the pads age / go through more heat cycles - they lose performance!

Agree with this. The first time I bought a Porsche I hadn't done all my homework so didn't know about this problem and resented the OPC failing it on its first ever MOT (somewhere else passed it, with an advisory note). While annoying, I should have just changed them. On my second Box the brakes were clean and I've kept them this way and the difference is night and day. Now if I'm away for a week and see even a small bit of corrosion on the disc surfaces on my return I take it straight out to burn it off.

Do you lave the car outside? My 911 stands for quite long periods, especially over winter but is always put away inside with hot discs and shows no corrosion at all.

[gl20]

REALIST123 said:

gl20 said:

MadMark911 said:

James - what I would say is that I bought my Boxster S just before it was 2 years old (at about 16,000 miles) and after I changed the discs and pads (at about 24,000 miles and 3 years old) - it stopped harder than it had ever done!

Amazing feeling of deceleration and less pedal pressure required too - they just "bit" so much harder, so do be aware that as they corrode and the pads age / go through more heat cycles - they lose performance!

Agree with this. The first time I bought a Porsche I hadn't done all my homework so didn't know about this problem and resented the OPC failing it on its first ever MOT (somewhere else passed it, with an advisory note). While annoying, I should have just changed them. On my second Box the brakes were clean and I've kept them this way and the difference is night and day. Now if I'm away for a week and see even a small bit of corrosion on the disc surfaces on my return I take it straight out to burn it off.

Do you lave the car outside? My 911 stands for quite long periods, especially over winter but is always put away inside with hot discs and shows no corrosion at all.

Yes - garage full of junk. But car gets driven about 5 days out of 7 so not normally a problem for me.

[MadMark911]

REALIST123 said:

Do you lave the car outside? My 911 stands for quite long periods, especially over winter but is always put away inside with hot discs and shows no corrosion at all.

Yes my car lived outside and was only used at weekends ....