V8 Vantage Brake Disc Minimum Thicknesses?
Discussion
Generally brake discs will have a minimum thickness after machining - the thinnest is disc is allowed to be with new pads fitted.
The wear limit is generally 2mm away from a new disc so a 26mm wear limit will likely come from a 28mm new disc
If you have a disc 0.3mm away from a wear limit it is advised you do not fit new pads (as the pad and its wear indicator will outlast the disc)
The wear limit is generally 2mm away from a new disc so a 26mm wear limit will likely come from a 28mm new disc
If you have a disc 0.3mm away from a wear limit it is advised you do not fit new pads (as the pad and its wear indicator will outlast the disc)
It really boils my pi55 about getting near to limits, it really depends how you drive and how much, lots to go into the mix here, possible scenarios are you have not had the car long and drive like miss daisy and only do 2k a year, or had it from new and it's 10 months old and you do 2 track days a month. the garage does not know which but baring in mind it services cars to make money it can only recommend "on safety grounds sir" you change them.Put the question in your mind by calling euro car parts with your reg and find out what the parts cost, remember no car maker manufacturers any of the brake systems they fit, this is not about cost cutting or running about with brakes about to fail it's about trust, a second opinion on how much they are worn will help your mind I'm sure
k20erham said:
It really boils my pi55 about getting near to limits, it really depends how you drive and how much, lots to go into the mix here, possible scenarios are you have not had the car long and drive like miss daisy and only do 2k a year, or had it from new and it's 10 months old and you do 2 track days a month. the garage does not know which but baring in mind it services cars to make money it can only recommend "on safety grounds sir" you change them.Put the question in your mind by calling euro car parts with your reg and find out what the parts cost, remember no car maker manufacturers any of the brake systems they fit, this is not about cost cutting or running about with brakes about to fail it's about trust, a second opinion on how much they are worn will help your mind I'm sure
Bare in mind though, that you've taken the car in for service and or work. It's the garage's duty to report back on their findings. It's down to you to decide if you want the work. I'd be more miffed if the garage didn't do a thorough job and overlooked items that could potentially need work in the future. It saves you being stranded at the side of the road one day or heaven forbid in a crash. The garage wouldn't want someone else looking over the vehicle after them saying, "Why didn't the garage who's just serviced this not pick up on X,Y,Z etc"It's a piece of engineering that needs maintaining properly for the longevity of it and for it's correct and proper operation.
It adds to your enjoyment and may save your life.
Never knock a garage that's doing their job properly
Brake discs are obviously and important component, especially with the speeds that our cars are capable of.
I have twice been told new discs are needed on daily drivers. Once by Kwik Fit, when I knew the discs were less than a quarter worn. Never did business with them again.
The second time by a Mercedes dealer. I said change pads, but not discs. Funny that, because they continued to service the car and ten years later, the same discs are on the car and they have never mentioned that matter again.
Hence the 2nd opinion, the customer has rightly been informed by the garage, would I trust them no way and I don't care who they are, don't ignore the advice get it qualified, like I explained if the OP does low miles they will last ?? 5 years, if he's got a track day done in this weekend, the garage have quite rightly reported as they should.
Interesting point about how I drive it.
I was nicknamed captain slow in the Maserati Club and never drove it faster (on a private road) than 120mph. I generally will rarely ever exceed about 95mph on such private roads. I rarely brake hard at speed, unless when I am curing the brake squeal that usually presents itself after my wife has been driving. I also do 2k-3k a year. I don't do track days.
I have spoken to one Indy who has said, if those are the real measurements, then change them.
The trouble is you cannot fault a garage for wanting to make money. It is why they are there. I want them to give me this information. But I would also appreciate if they used their own experience to tell me what they thought was reasonable and what was must-do's.
If anyone has a recommendation of who might be reasonable to speak to, please PM me a name.
I was nicknamed captain slow in the Maserati Club and never drove it faster (on a private road) than 120mph. I generally will rarely ever exceed about 95mph on such private roads. I rarely brake hard at speed, unless when I am curing the brake squeal that usually presents itself after my wife has been driving. I also do 2k-3k a year. I don't do track days.
I have spoken to one Indy who has said, if those are the real measurements, then change them.
The trouble is you cannot fault a garage for wanting to make money. It is why they are there. I want them to give me this information. But I would also appreciate if they used their own experience to tell me what they thought was reasonable and what was must-do's.
If anyone has a recommendation of who might be reasonable to speak to, please PM me a name.
rear disc @ new = 28mm
rear disc @ service limit = 26mm
easy way to check wear at home is to measure depth of slats
depth when new = approx 1.50mm
if disc was on service limit of 26 mm, the slat depth would therefore be 0.5 mm (each side)
I wouldn't advise fitting a new pad to a disc that was @ 26.5mm unless the disc was perfectly flat and not rippled like a record or pad will not bed in, braking performance likely be reduced but importantly, so would DSC performance.
When just wearing past the 0.5mm slat thickness limit, disc looks like this - as long as pad is meaty and not approaching pad minimum wear limit you will get away with a disc being this thin, nothing is going to fall off / crack - this particular disc came off a track car
So, if in doubt about whether to change discs based off service report, just ask for a picture of disc face showing slat depth and surface condition and make your own judgement call based on annual mileage / harshness of use / if you want a trip back inside a workshop mid service interval or take care of everything in one hit
Whilst it is possible to source cheaper parts from outside OEM, be careful spec is like-for-like, for instance i have seen a copy of the OEM pad not having wear lead indicators. When the pad wears thin the pins will contact disc, the wear light illuminates prior to this happening, if pins contact disc, disc is pretty much wrecked, if disc was new / this was first set of pads used on it, then buying the cheaper pad without wear lead indicator is false economy.
rear disc @ service limit = 26mm
easy way to check wear at home is to measure depth of slats
depth when new = approx 1.50mm
if disc was on service limit of 26 mm, the slat depth would therefore be 0.5 mm (each side)
I wouldn't advise fitting a new pad to a disc that was @ 26.5mm unless the disc was perfectly flat and not rippled like a record or pad will not bed in, braking performance likely be reduced but importantly, so would DSC performance.
When just wearing past the 0.5mm slat thickness limit, disc looks like this - as long as pad is meaty and not approaching pad minimum wear limit you will get away with a disc being this thin, nothing is going to fall off / crack - this particular disc came off a track car
So, if in doubt about whether to change discs based off service report, just ask for a picture of disc face showing slat depth and surface condition and make your own judgement call based on annual mileage / harshness of use / if you want a trip back inside a workshop mid service interval or take care of everything in one hit
Whilst it is possible to source cheaper parts from outside OEM, be careful spec is like-for-like, for instance i have seen a copy of the OEM pad not having wear lead indicators. When the pad wears thin the pins will contact disc, the wear light illuminates prior to this happening, if pins contact disc, disc is pretty much wrecked, if disc was new / this was first set of pads used on it, then buying the cheaper pad without wear lead indicator is false economy.
leerandle said:
If someone has just replaced the pads (because they did it on the cheap) and there is plenty of meat left on them and the discs being near limit, is it worth swapping discs and pads at the same time ? Or could you just swap the discs and keep the existing pads ?
the answer to this question could be quite long, advising limits of minimum disc / maximum pad and visa-versa thresholds / combinations.simple way to answer it though, is, if stringing consumables out for the longest life absolutely possible without consideration to brake performance. The ultimate no go is change pads within 500 miles of wear light illuminating on dash, and change discs when slat face is just at point of disappearing. But with an axle set of discs and pads fitted at service, for let's say £520+VAT, stringing safety critical brakes out this way isn't perhaps how an Aston should be fettled?
The issue I have is that my AM dealer, seems to guess everything. In reality as soon as you've driven 10 miles every part has a degree of wear, you may well drive 5000 miles in the following week so any recommendation to change can be justified by the dealer if need be.
I recently complained to Gaydon about the vagueness of the service reporting, it seems that (in my experience at least) they pick any random high number out of thin air for wear on brakes. I believe for a premium priced service we should get exact measurements with upper and lower parameters and we can make our own minds up. It shouldn't take more than a few seconds to measure a set of pads/discs. My service in May 2014 said that my handbrake pads were 80% worn, which at the time seemed a bit strange as I'm not sure how they actually wear, 18 months later I'm changing the rear pads so Rick at BMG supplied me a set of handbrake pads as well. The new ones are nearly identical in thickness to what's on the car, so I didn't bother changing them. I'd be intrigued if anyone knows how thick a new handbrake pad should be. I'm pretty sure that my dealer was (trying to) rip me off.
I recently complained to Gaydon about the vagueness of the service reporting, it seems that (in my experience at least) they pick any random high number out of thin air for wear on brakes. I believe for a premium priced service we should get exact measurements with upper and lower parameters and we can make our own minds up. It shouldn't take more than a few seconds to measure a set of pads/discs. My service in May 2014 said that my handbrake pads were 80% worn, which at the time seemed a bit strange as I'm not sure how they actually wear, 18 months later I'm changing the rear pads so Rick at BMG supplied me a set of handbrake pads as well. The new ones are nearly identical in thickness to what's on the car, so I didn't bother changing them. I'd be intrigued if anyone knows how thick a new handbrake pad should be. I'm pretty sure that my dealer was (trying to) rip me off.
gilbo said:
Bare in mind though, that you've taken the car in for service and or work. It's the garage's duty to report back on their findings. It's down to you to decide if you want the work. I'd be more miffed if the garage didn't do a thorough job and overlooked items that could potentially need work in the future. It saves you being stranded at the side of the road one day or heaven forbid in a crash. The garage wouldn't want someone else looking over the vehicle after them saying, "Why didn't the garage who's just serviced this not pick up on X,Y,Z etc"
It's a piece of engineering that needs maintaining properly for the longevity of it and for it's correct and proper operation.
It adds to your enjoyment and may save your life.
Never knock a garage that's doing their job properly
It's a piece of engineering that needs maintaining properly for the longevity of it and for it's correct and proper operation.
It adds to your enjoyment and may save your life.
Never knock a garage that's doing their job properly
Edited by huggy1 on Friday 6th November 23:58
A main dealer is highly unlikely to lie about measurements like this. Ask them to retain the old parts if you want to check them and take a micrometer along. If they're not what they told you, tell them to put them back on or negotiate a better price
That close to the minimums for a safety item I'd be inclined to change them.
Haven't you just bought the car?? Did you know the discs needed changing at that point??
I'm also not sure I'd bother using pads that had been used on an old set of discs for any length of time. When I was 17 tooling about in a MkII Escort that was more P38 than metal I might have...but not on a car with 3x the power and nearly twice the weight to lug around. And, of course, now I'm >2.5x this age I value my and others' safety that bit more
btw, when main dealers give me the advisories I ask them what the brand new measurements are. I can then work out what I want to do from %age worn - helped by me being the only owner of this car so I know wear rates .
That close to the minimums for a safety item I'd be inclined to change them.
Haven't you just bought the car?? Did you know the discs needed changing at that point??
I'm also not sure I'd bother using pads that had been used on an old set of discs for any length of time. When I was 17 tooling about in a MkII Escort that was more P38 than metal I might have...but not on a car with 3x the power and nearly twice the weight to lug around. And, of course, now I'm >2.5x this age I value my and others' safety that bit more
btw, when main dealers give me the advisories I ask them what the brand new measurements are. I can then work out what I want to do from %age worn - helped by me being the only owner of this car so I know wear rates .
rossyl said:
...
The trouble is you cannot fault a garage for wanting to make money.....
Panto season so....Ohhhhhhh yes you can.The trouble is you cannot fault a garage for wanting to make money.....
rossyl said:
...
It is why they are there. ...
And ohhhhhhh no it isn't (well not really).It is why they are there. ...
They are there to service high quality cars. And to do so with commensurate high quality and integrity.
If they do this, they will make money. Lots of it knowing main dealer prices.
Main dealer recommended change points are conservative IMO, but if you have a decent chat with them it's all usually OK IME.
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