Front disc inside edges rusted
Discussion
After taking the boxster s (06 my) in for it's mot the guys warned us about the inside edge of the discs having some fairly bad pitting.
As the car only gets very occasional use we're always very careful to dry the rotors & pads off after washing etc but we didn't think that the inside edges would be any different to the outer edges.
Any ideas why this might be? On the track cars we use we've sometimes noticed the inside pads wear out quicker but we don't understand why this is happening with the discs?
They aren't bad enough to need replacing yet but seeing as the car gets such light use we obviously want the consumables to last as long as possible
any ideas anyone?
As the car only gets very occasional use we're always very careful to dry the rotors & pads off after washing etc but we didn't think that the inside edges would be any different to the outer edges.
Any ideas why this might be? On the track cars we use we've sometimes noticed the inside pads wear out quicker but we don't understand why this is happening with the discs?
They aren't bad enough to need replacing yet but seeing as the car gets such light use we obviously want the consumables to last as long as possible
any ideas anyone?
Hi ,
I have had the same problem on my 996tt. Had the front discs, both faces skimmed. New Pads. It has worked but 1 year on they are starting again. (I have done 10000 miles this year!)
Whilst sorting out my Turbo corrosion problem ( On going) I have noticed my rear Discs have to be done as well. Much cheaper than buying new discs just make sure the machine shop is competent at doing them. Might sound daft but you get bounch from the cutting tool which can ruin the disc face. Also there is a wear limit for the discs. Once this limit has been reached you cant go any further. I think it is called "disc run out". I had the ammount written down once I will have to try and find it. I think I gaot it from a workshop CD.
Frank
I have had the same problem on my 996tt. Had the front discs, both faces skimmed. New Pads. It has worked but 1 year on they are starting again. (I have done 10000 miles this year!)
Whilst sorting out my Turbo corrosion problem ( On going) I have noticed my rear Discs have to be done as well. Much cheaper than buying new discs just make sure the machine shop is competent at doing them. Might sound daft but you get bounch from the cutting tool which can ruin the disc face. Also there is a wear limit for the discs. Once this limit has been reached you cant go any further. I think it is called "disc run out". I had the ammount written down once I will have to try and find it. I think I gaot it from a workshop CD.
Frank
It's not so much the rusting that's annoying,rather the fact we thought we had it under control by the look of the outer faces.
I guess I'm right in thinking that to provide such good stopping power the brakes have a high iron content which leads to excessive rusting yeah?
Is the only answer a 50 mile country road bast after washing?
Shame .......
I guess I'm right in thinking that to provide such good stopping power the brakes have a high iron content which leads to excessive rusting yeah?
Is the only answer a 50 mile country road bast after washing?
Shame .......
Hi
It's very common on Porsches. It appears to be a characteristic of the braking system. No one has been able to explain the mechanism of how it occurs to me but my Indy who has been in the business for many years assures me it is very common indeed, so I accept this as empirical data.
The best way to avoid or at least minimise it is to use your brakes very hard over several successive stops. Hard enough so that the ABS is about to activate. It's the sort of braking that will occur on a track day.
If your car does suffer from it you can prolong the life of the discs by having them ground on the car. This is a Porsche approved process and an Indy with the correct kit will do it for around £70 per corner. I'm told that the older cars 964 and 993 have more meat on the discs so can be ground a couple of times, where as later cars 996 /Boxster etc have less material, so probably only once.
pp
It's very common on Porsches. It appears to be a characteristic of the braking system. No one has been able to explain the mechanism of how it occurs to me but my Indy who has been in the business for many years assures me it is very common indeed, so I accept this as empirical data.
The best way to avoid or at least minimise it is to use your brakes very hard over several successive stops. Hard enough so that the ABS is about to activate. It's the sort of braking that will occur on a track day.
If your car does suffer from it you can prolong the life of the discs by having them ground on the car. This is a Porsche approved process and an Indy with the correct kit will do it for around £70 per corner. I'm told that the older cars 964 and 993 have more meat on the discs so can be ground a couple of times, where as later cars 996 /Boxster etc have less material, so probably only once.
pp
mankey said:
Surely at £70 a wheel you're beginning to wonder whether to replace aren't you?
Yes, I thought about this. However, for £70 a corner you drive the car in to my Indy, the discs are ground on the car. I then then drive the car away having drunk frothy coffee and eaten their biscuits. I don't get my hands dirty and it doubles the life of the discs.The alternative is that I change the discs on my driveway. This is fine when the weather is good and I have the time. It will cost me more than £70 a corner and the discs will inevitably rust again after a period of time.
The other option, as somebody else mentioned, is to remove the discs and have them skimmed at a workshop.
pp
cragswinter said:
It's not so much the rusting that's annoying,rather the fact we thought we had it under control by the look of the outer faces.
I guess I'm right in thinking that to provide such good stopping power the brakes have a high iron content which leads to excessive rusting yeah?
Is the only answer a 50 mile country road bast after washing?
Shame .......
After washing my 996tt I always take it out and do a few fairly severe stops from 60 - 70mph. Almost emergency stops. You've got to really heat them up, get all that water evaporated quickly. I guess I'm right in thinking that to provide such good stopping power the brakes have a high iron content which leads to excessive rusting yeah?
Is the only answer a 50 mile country road bast after washing?
Shame .......
Noticed some rust on the inner inch diameter on my fronts only the other day so whipped
them off for a look and sure enough the inside is far worse with a bit of scoring so
they're off to get skimmed. Car doesn't get much mileage and I may be guilty of rolling
it out the garage, washing it and putting it back...( I know, I know, it'll be getting
a thrashing after a clean in future!). I'll be pulling off the back discs for a look once the
fronts are done, I could just look under the car but where's the fun in that, and you get a
chance to give wheels, calipers, inner arches a good clean.
them off for a look and sure enough the inside is far worse with a bit of scoring so
they're off to get skimmed. Car doesn't get much mileage and I may be guilty of rolling
it out the garage, washing it and putting it back...( I know, I know, it'll be getting
a thrashing after a clean in future!). I'll be pulling off the back discs for a look once the
fronts are done, I could just look under the car but where's the fun in that, and you get a
chance to give wheels, calipers, inner arches a good clean.
RDM said:
Noticed some rust on the inner inch diameter on my fronts only the other day so whipped
them off for a look and sure enough the inside is far worse with a bit of scoring so
they're off to get skimmed. Car doesn't get much mileage and I may be guilty of rolling
it out the garage, washing it and putting it back...( I know, I know, it'll be getting
a thrashing after a clean in future!). I'll be pulling off the back discs for a look once the
fronts are done, I could just look under the car but where's the fun in that, and you get a
chance to give wheels, calipers, inner arches a good clean.
be careful mate you know where these things lead to.....them off for a look and sure enough the inside is far worse with a bit of scoring so
they're off to get skimmed. Car doesn't get much mileage and I may be guilty of rolling
it out the garage, washing it and putting it back...( I know, I know, it'll be getting
a thrashing after a clean in future!). I'll be pulling off the back discs for a look once the
fronts are done, I could just look under the car but where's the fun in that, and you get a
chance to give wheels, calipers, inner arches a good clean.
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