Mk7 Golf GTI - severe scoring of rear discs
Discussion
Anyone come across this before? I've searched PH and drawn a blank but there's a thread on the Golf R forum and another Golf one.
One of the rear discs (other side's the same):
Here's one of the fronts by comparison:
The wheels and calipers aren't always that dirty, honest... Car last used three days before pics taken.
Total mileage currently 22K done in about 26 months. However, scoring had begun long ago - maybe a year/12K miles.
In 40-odd years of motoring and generally having new cars at each change, and putting 40K to 80K miles on them I've never had an issue with brakes or even needed new pads. I don't hang around either. I wouldn't say I'm a heavy braker but stopping 1.5 tonnes of car from 70 mph or so puts the discs and calipers to work and ought to keep the discs clean. And I haven't been off road or driven in 'abrasive' conditions.
My local dealer says I need new discs and pads. What, at 20K miles? Any ideas as to cause or how to address? Worth getting them skimmed?
One of the rear discs (other side's the same):
Here's one of the fronts by comparison:
The wheels and calipers aren't always that dirty, honest... Car last used three days before pics taken.
Total mileage currently 22K done in about 26 months. However, scoring had begun long ago - maybe a year/12K miles.
In 40-odd years of motoring and generally having new cars at each change, and putting 40K to 80K miles on them I've never had an issue with brakes or even needed new pads. I don't hang around either. I wouldn't say I'm a heavy braker but stopping 1.5 tonnes of car from 70 mph or so puts the discs and calipers to work and ought to keep the discs clean. And I haven't been off road or driven in 'abrasive' conditions.
My local dealer says I need new discs and pads. What, at 20K miles? Any ideas as to cause or how to address? Worth getting them skimmed?
I've seen similar on Briskoda about Fabia rear brakes, some people even needing new discs after 1 year. Seems to me there's not much rear brake bias so the corrosion doesn't get cleaned up under normal braking. Whenever I've seen the corrosion start to build up I've just done some heavy braking and they've cleaned right up. Might be worth doing that and seeing if they clean up first?
If you can do 80K miles without needed pads then you're not using the brakes much.
I had this on a Merc at 40K - dealer said discs were heavily pitted and they were baffled as they were hardly worn. I really only use the car on long motorway trips so was rarely braking.
Just had discs and pads all round on daughter's more basic 6yr old / 60K mile Golf6. I'd noted the rear discs haad stayed shiny until recently but last time I looked they'd deteriorated a lot - I think once areas of rust start to rub the pad away the disc never cleans up, even with heavy braking.
We had a Honda Jazz and the rear discs on those are noted for always looking bad as they do so little work. Of course Honda is a bit different to VW and they changed them at 3yrs as goodwill. They're supposed to have increased the pressure on the rears on later models.
I had this on a Merc at 40K - dealer said discs were heavily pitted and they were baffled as they were hardly worn. I really only use the car on long motorway trips so was rarely braking.
Just had discs and pads all round on daughter's more basic 6yr old / 60K mile Golf6. I'd noted the rear discs haad stayed shiny until recently but last time I looked they'd deteriorated a lot - I think once areas of rust start to rub the pad away the disc never cleans up, even with heavy braking.
We had a Honda Jazz and the rear discs on those are noted for always looking bad as they do so little work. Of course Honda is a bit different to VW and they changed them at 3yrs as goodwill. They're supposed to have increased the pressure on the rears on later models.
Edited by Sheepshanks on Wednesday 1st March 18:26
Is it actual scoring or is it just that some areas have been unevenly cleared of corrosion/salt?
As said, the rears to very little on car like this, particularly a hot model which will have bigger brakes on the front. If you're a light braker and/or do a lot of motorway miles then it could easily happen, either through deterioration of the disc itself or through deterioration of the pad and then the disc as a consequence.
Worth giving it a good bedding cycle (I.e. a controlled pasting) to see if it clears up, if you still struggle you could even try loading the car up with some weight in the back and braking really hard to get the EBD going in shifting some pressure to the rear.
Personally if it's not creating any noise issues, judder or noticeable drop in brake performance I'd be inclined to ignore it. The first two will more than likely appear before the last.
As said, the rears to very little on car like this, particularly a hot model which will have bigger brakes on the front. If you're a light braker and/or do a lot of motorway miles then it could easily happen, either through deterioration of the disc itself or through deterioration of the pad and then the disc as a consequence.
Worth giving it a good bedding cycle (I.e. a controlled pasting) to see if it clears up, if you still struggle you could even try loading the car up with some weight in the back and braking really hard to get the EBD going in shifting some pressure to the rear.
Personally if it's not creating any noise issues, judder or noticeable drop in brake performance I'd be inclined to ignore it. The first two will more than likely appear before the last.
The Wookie said:
Is it actual scoring or is it just that some areas have been unevenly cleared of corrosion/salt?
As said, the rears to very little on car like this, particularly a hot model which will have bigger brakes on the front. If you're a light braker and/or do a lot of motorway miles then it could easily happen, either through deterioration of the disc itself or through deterioration of the pad and then the disc as a consequence.
Worth giving it a good bedding cycle (I.e. a controlled pasting) to see if it clears up, if you still struggle you could even try loading the car up with some weight in the back and braking really hard to get the EBD going in shifting some pressure to the rear.
Personally if it's not creating any noise issues, judder or noticeable drop in brake performance I'd be inclined to ignore it. The first two will more than likely appear before the last.
It is actual scoring. I accept that my car usage and driving style combine to minimise brake wear but I've been doing this for years and it's never happened before.As said, the rears to very little on car like this, particularly a hot model which will have bigger brakes on the front. If you're a light braker and/or do a lot of motorway miles then it could easily happen, either through deterioration of the disc itself or through deterioration of the pad and then the disc as a consequence.
Worth giving it a good bedding cycle (I.e. a controlled pasting) to see if it clears up, if you still struggle you could even try loading the car up with some weight in the back and braking really hard to get the EBD going in shifting some pressure to the rear.
Personally if it's not creating any noise issues, judder or noticeable drop in brake performance I'd be inclined to ignore it. The first two will more than likely appear before the last.
I'm in two minds about what to do: get it sorted (at some considerable cost) or leave it (on the basis that the brakes still make a fine job of stopping the car). A mate who does a fair bit of amateur spannering reckons the rear pads are a bit thin.
ETA: I think the discs are too far gone to respond to some stand-on-pedal braking.
Edited by Maxym on Wednesday 1st March 19:34
Maxym said:
It is actual scoring. I accept that my car usage and driving style combine to minimise brake wear but I've been doing this for years and it's never happened before.
I'm in two minds about what to do: get it sorted (at some considerable cost) or leave it (on the basis that the brakes still make a fine job of stopping the car). A mate who does a fair bit of amateur spannering reckons the rear pads are a bit thin.
ETA: I think the discs are too far gone to respond to some stand-on-pedal braking.
Even at minimum thickness you're not going to have a problem, but if they're at minimum depth (which if they're heavily grooved or lipped they likely will be) you may as well just change themI'm in two minds about what to do: get it sorted (at some considerable cost) or leave it (on the basis that the brakes still make a fine job of stopping the car). A mate who does a fair bit of amateur spannering reckons the rear pads are a bit thin.
ETA: I think the discs are too far gone to respond to some stand-on-pedal braking.
Edited by Maxym on Wednesday 1st March 19:34
ETA - just noticed the low mileage, unless you goon around a lot of roundabouts and are digging into the ESP a lot then that's not right. Likely a pad batch issue, not sure who supplies those but I've seen a rapid wearing pads slip through a well known quality pad manufacturers quality control before
Edited by The Wookie on Wednesday 1st March 20:02
Sorry but that looks like deposit to me - which may feels to the touch exactly like scoring. I would go on a late night repeated intense braking session on the very edge of ABS triggering (x10 60 to 20) and see what happens. If it is scoring then no big loss but it is uneven glazing it should show signs of cutting through it.
I'm probably wrong but worth a check.
I'm probably wrong but worth a check.
nickfrog said:
Sorry but that looks like deposit to me - which may feels to the touch exactly like scoring. I would go on a late night repeated intense braking session on the very edge of ABS triggering (x10 60 to 20) and see what happens. If it is scoring then no big loss but it is uneven glazing it should show signs of cutting through it.
I'm probably wrong but worth a check.
If it were a deposit of some sort it would scrape off, wouldn't it? I mean, I could see if I could remove what looks like scoring with a scraper of some kind...?I'm probably wrong but worth a check.
Thanks for all the comments, suggestions, etc. Much appreciated.
nickfrog said:
... repeated intense braking session on the very edge of ABS triggering (x10 60 to 20) and see what happens.
Mate of mine does that in his Boxster which lives outside and is only used at weekends. He reckons it's hard on the tyres but they're cheaper than Porsche brakes!On my Merc, I was surprised how bad the inside face of the discs looked - doesn't make any sense to me, as the piston is on the inside but while the outside looked a bit ropey, the insides where terrible.
Maxym said:
ETA: I think the discs are too far gone to respond to some stand-on-pedal braking.
If you really think that, then you shouldn't be driving on them.Edited by Maxym on Wednesday 1st March 19:34
But they're not. The discs look virtually untouched, wear-wise, and that scoring is a fraction of a mm deep. The brakes won't even notice. I'd do some hard stops and if it's fine, not worry about it, personally.
It's kind of embedded and baked on the disc so that's why if feels like scoring. After a track day where I have overheated the pads it can take 10 days of road braking to eventually go. I even water the discs at night as the rust in the morning helps speed up the healing process (how weird).
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