Replacing brake pads and discs
Discussion
Last Sunday whilst on holiday in Lucerne, Switzerland, the brake pad warning light came on whilst driving. Subsequently went off again and didn't come on after switching engine off and on afterwards later that day.
A quick search on the internet at the time suggested that it must be the front pads as there are no wear sensors on rear pads (car is a 2012 Audi S4 avant s-tronic). I'm not mechanically minded so not entirely sure what i'm looking at but thought I could see some meat on the front pads but struggling to see anything on the rears but this could also be due to the spokes and caliper placement restrcting the view.
As I was returning home to London on Monday, I took the car to Audi Lucerne to ask for advice on which pads needed replacing and whether they would need to be done immediately or if they would last the 750mile approx journey home.
The technician took a quick look around the car (wheels on) car on ground, using a torch and said it was the rear inner pads that were worn and should be good for 3,000 km before metal to metal contact. This put my mind at rest and I drove home on Monday without incident. Warning light did not come in at all on the journey despite several stops.
Yesterday I took the car to an Audi dealer (won't mention which one, and not necessarily the local dealer), and asked them to check which pads needed replacing. They carried out an inspection (car on ground, didn't leave the customer car park) and came back saying that pads and discs front and rear were 70% worn and therefore all needed replacing.
The car has done 30k miles (approx 8k a year) and no mention was made on the full service in May (mileage approx 27k) that pads and disc replacement would be imminent.
I don't want to be flamed about running costs - i'm not complaining about the cost (although 950 odd for 4 nee pads and discs sounds a bit pricey), but I would have thought that the discs don't need replacing just yet if they are only 70% worn and I would have expected them to last longer. In fact, 70% wear would imply an expected life of around 45k miles which I think is more reasonable.
I bought the car at 3 years old with 13k and its not had any brake replacement done in my ownership. I feel that 30k in the original pads is pretty good going but I'd have thought fronts would wear quicker than the rears. I'd also expect that discs last longer than pads.
Is there an easy way for me to measure the discs and pads myself as I find it surprising that pads and discs both front and rear are all 70% worn. Perhaps i'm being a bit cynical.
As it stands I'm currently booked to change the pads but hold off on the discs.
FWiW car is used mainly for school run, no track days and little motorway work.
A quick search on the internet at the time suggested that it must be the front pads as there are no wear sensors on rear pads (car is a 2012 Audi S4 avant s-tronic). I'm not mechanically minded so not entirely sure what i'm looking at but thought I could see some meat on the front pads but struggling to see anything on the rears but this could also be due to the spokes and caliper placement restrcting the view.
As I was returning home to London on Monday, I took the car to Audi Lucerne to ask for advice on which pads needed replacing and whether they would need to be done immediately or if they would last the 750mile approx journey home.
The technician took a quick look around the car (wheels on) car on ground, using a torch and said it was the rear inner pads that were worn and should be good for 3,000 km before metal to metal contact. This put my mind at rest and I drove home on Monday without incident. Warning light did not come in at all on the journey despite several stops.
Yesterday I took the car to an Audi dealer (won't mention which one, and not necessarily the local dealer), and asked them to check which pads needed replacing. They carried out an inspection (car on ground, didn't leave the customer car park) and came back saying that pads and discs front and rear were 70% worn and therefore all needed replacing.
The car has done 30k miles (approx 8k a year) and no mention was made on the full service in May (mileage approx 27k) that pads and disc replacement would be imminent.
I don't want to be flamed about running costs - i'm not complaining about the cost (although 950 odd for 4 nee pads and discs sounds a bit pricey), but I would have thought that the discs don't need replacing just yet if they are only 70% worn and I would have expected them to last longer. In fact, 70% wear would imply an expected life of around 45k miles which I think is more reasonable.
I bought the car at 3 years old with 13k and its not had any brake replacement done in my ownership. I feel that 30k in the original pads is pretty good going but I'd have thought fronts would wear quicker than the rears. I'd also expect that discs last longer than pads.
Is there an easy way for me to measure the discs and pads myself as I find it surprising that pads and discs both front and rear are all 70% worn. Perhaps i'm being a bit cynical.
As it stands I'm currently booked to change the pads but hold off on the discs.
FWiW car is used mainly for school run, no track days and little motorway work.
I don't know the car but the discs should last longer than that and rears way longer as they do a lot let work. If you can find some one that works on these cars they should be able to tell you the minimum width of the disc and that should be easy to check. In the morning, before you drive the car (or it will be hot) run your finger across the disc. It should be flattish with no big lip.
You can measure the pads with a rule, or vernier calipers. There should however be wear indicators which can visually check.
You can measure the discs with a micrometer.
As for the cost, that is expensive, but I'm not sure what the Audi parts cost along with an hour or so's labour.
For example pattern Brembos for a full set are just under £300, some might want something more premium however (personally I think people often over-estimate their performance needs and they would be fine).
You can measure the discs with a micrometer.
As for the cost, that is expensive, but I'm not sure what the Audi parts cost along with an hour or so's labour.
For example pattern Brembos for a full set are just under £300, some might want something more premium however (personally I think people often over-estimate their performance needs and they would be fine).
An approved dealer / franchised Audi workshop is always going to try to sell you the maximum they can, sometimes even if it's not needed. A smaller independent garage might be different, but likewise places like Kwik Fit will do the same. Like you have admitted yourself, you're not mechanically minded but you know there's something wrong with the brakes. I'm surprised they didn't offer to replace the handbrake cables whilst they were at it...
Quick scoot online looks as though you could get Bosch pads and discs all round for around £250. So that's £700 labour - depends how keen you are on having Audi do it "themselves", but I'd be willing to bet an independent garage worth their salt could do it in a couple of hours.
The best way to tell if discs are past their best is whether they have a significant 'lip' formed on their outer edge, as this indicates they have reduced in thickness beyond what the manufacturer recommends. There will always be a greater thickness here as it's not within the swept pad area, but if it's really bad it should be obvious. You can check with a micrometer tool the overall thickness if you wish. The other thing to check for is any substantial scoring or surface cracking.
Quick scoot online looks as though you could get Bosch pads and discs all round for around £250. So that's £700 labour - depends how keen you are on having Audi do it "themselves", but I'd be willing to bet an independent garage worth their salt could do it in a couple of hours.
The best way to tell if discs are past their best is whether they have a significant 'lip' formed on their outer edge, as this indicates they have reduced in thickness beyond what the manufacturer recommends. There will always be a greater thickness here as it's not within the swept pad area, but if it's really bad it should be obvious. You can check with a micrometer tool the overall thickness if you wish. The other thing to check for is any substantial scoring or surface cracking.
C.A.R. said:
An approved dealer / franchised Audi workshop is always going to try to sell you the maximum they can, sometimes even if it's not needed. A smaller independent garage might be different, but likewise places like Kwik Fit will do the same. Like you have admitted yourself, you're not mechanically minded but you know there's something wrong with the brakes. I'm surprised they didn't offer to replace the handbrake cables whilst they were at it...
Quick scoot online looks as though you could get Bosch pads and discs all round for around £250. So that's £700 labour - depends how keen you are on having Audi do it "themselves", but I'd be willing to bet an independent garage worth their salt could do it in a couple of hours.
The best way to tell if discs are past their best is whether they have a significant 'lip' formed on their outer edge, as this indicates they have reduced in thickness beyond what the manufacturer recommends. There will always be a greater thickness here as it's not within the swept pad area, but if it's really bad it should be obvious. You can check with a micrometer tool the overall thickness if you wish. The other thing to check for is any substantial scoring or surface cracking.
Quite. I can change pads and a disk in 30 mins per corner (ish) on my driveway so a full ketted garage with car lift and all the tools to hand should be able to do it in at least 90 mins I'd have thought.Quick scoot online looks as though you could get Bosch pads and discs all round for around £250. So that's £700 labour - depends how keen you are on having Audi do it "themselves", but I'd be willing to bet an independent garage worth their salt could do it in a couple of hours.
The best way to tell if discs are past their best is whether they have a significant 'lip' formed on their outer edge, as this indicates they have reduced in thickness beyond what the manufacturer recommends. There will always be a greater thickness here as it's not within the swept pad area, but if it's really bad it should be obvious. You can check with a micrometer tool the overall thickness if you wish. The other thing to check for is any substantial scoring or surface cracking.
It's such an easy job to learn though, OP, if you don't want to pay others to do it for you.
mgv8 said:
I don't know the car but the discs should last longer than that and rears way longer as they do a lot let work
Well that's not necessarily the case. Traction control, stability control, brake based torque vectoring and dynamic cruise control all use the brakes to function. So it's not uncommon for the rears pads to wear out first.xxChrisxx said:
mgv8 said:
I don't know the car but the discs should last longer than that and rears way longer as they do a lot let work
Well that's not necessarily the case. Traction control, stability control, brake based torque vectoring and dynamic cruise control all use the brakes to function. So it's not uncommon for the rears pads to wear out first.It's impossible to give generic figures for 'reasonable life', as too many factors impact on wear. What has been stated doesn't seem out of the ordinary but some people can see well over 100,000 miles out of a set of pads, others a couple of thousand. Different drivers, different conditions.
Usually the pad wear light has quite a reasonable safety margin built in as far as mileage until replacement is critical.
The problem with extended service intervals is that garages are often replacing discs/pads at what some consider to be too early a stage, whereas the reality is they might be fine for 5,000-10,000 miles, but not 15 or 20,000. Many people see a car as a white goods, that gets serviced, if you're lucky, once every 12 months, or 2 years.
It is possible you might have a sticking caliper, particularly if the inner pad is worn noticeably more than the outer pad.
Jaguar XFs, particularly the earlier ones, are renowned for getting through rear pads in pretty short mileages, I've heard of 6,000 miles being not unusual.
Edited by tonys on Thursday 24th August 14:57
xxChrisxx said:
mgv8 said:
I don't know the car but the discs should last longer than that and rears way longer as they do a lot let work
Well that's not necessarily the case. Traction control, stability control, brake based torque vectoring and dynamic cruise control all use the brakes to function. So it's not uncommon for the rears pads to wear out first.Is the light a pad wear warning light, or does it double as something else (ABS-T/C)?
catman said:
Is there any reason why you're only going to Audi garages for advice? There are lots of independant garages out there, who won't charge that much and many who won't see you as an opportunity to do unnecessary work.
Tim
Good point. So far the car has been covered under warranty and came with a service pack so no need to take it out of the dealer network. I'll probably take to an independent for second opinion.Tim
mgv8 said:
I don't know the car but the discs should last longer than that and rears way longer as they do a lot let work. If you can find some one that works on these cars they should be able to tell you the minimum width of the disc and that should be easy to check. In the morning, before you drive the car (or it will be hot) run your finger across the disc. It should be flattish with no big lip.
This is what I thought but I understand that ESC and electronic handbrake will shorten the life of the rears. Also, when changing over from winter to summer tyres I usually feel the disc for a lip. But as i'm not mechanically minded I'm not able to judge what is acceptable.
Pica-Pica said:
xxChrisxx said:
mgv8 said:
I don't know the car but the discs should last longer than that and rears way longer as they do a lot let work
Well that's not necessarily the case. Traction control, stability control, brake based torque vectoring and dynamic cruise control all use the brakes to function. So it's not uncommon for the rears pads to wear out first.Is the light a pad wear warning light, or does it double as something else (ABS-T/C)?
Pads get the most punishment on the inside simply due to that being where the pistons are.
Would take a few YouTube lessons on changing pads and discs it's one of those jobs that can be done yourself and the peace of mind it brings will more than make up for oily hands. If you're travelling over 1000 miles it's a good idea to learn a bit about jobs you can do and parts&tools to carry. The front pads are subject to 80% of the breaking thus need changed twice as much as the rear.
Don't ignore warning lights that represent your brakes. Typically changing brake pads won't take a novice more than an hour for both front callipers.
Would take a few YouTube lessons on changing pads and discs it's one of those jobs that can be done yourself and the peace of mind it brings will more than make up for oily hands. If you're travelling over 1000 miles it's a good idea to learn a bit about jobs you can do and parts&tools to carry. The front pads are subject to 80% of the breaking thus need changed twice as much as the rear.
Don't ignore warning lights that represent your brakes. Typically changing brake pads won't take a novice more than an hour for both front callipers.
I hope so, and I hope he survived. Casual advice to take the wheels off and have a look at the brake pads, to someone clearly not used to self-servicing who will not have axle stands and only the jack provided by the car maker, is unwise.
Self-servicing must include H&S observation as strict, or stricter, than in a dealer, as often the operator will be alone.
John
Self-servicing must include H&S observation as strict, or stricter, than in a dealer, as often the operator will be alone.
John
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