Our car's done 50,000 miles. Should it need new discs?

How badly worn is a disk that needs replacing? I can feel a step of about 1.5mm on the edge of the disc where the brake pads have worn away the braking surface, is this on the verge on needing replacement?

Bah. Mechanics trying to generate recession-busting work or genuine requirement?

I fear the former

I'd guess the latter – 1.5mm of wear and a step is quite a lot. if you're that worried most manufacturers state how much is 'acceptable' in terms of wear – google might help.

50k doesn't sound too bad for discs to be honest, depends on the type of driving you do. 1.5mm doesn't sound like a lot though. Is it an MOT failure? If not then just change the pads.

Oh. OK, maybe it's fine – I'll do a bit more research. Thanks.

(no, not an MOT failure, just a service, but it may be later in the year)

Cheers,

Ben

whats the run out on them?

Disks are cheep (£15 for standard ones usualy) but car makers often make them a PITA to replace by moving them inboard of the hub.

With a 1.5mm step its replacement time and thats without finding any cracks or uneven wear. Easy DIYjob take about 1hr and about £70 in parts depending on your car.

It's much more common for discs and pads to need replacing together since the asbestos (i think) content of the discs was removed.

1.5 mm step on the disc – assume the same thee other side – thats 3mm worn off the disc. Thats a lot Replace now IMO.

50 000 miles is OK if not amazing life for a disc. Using sinterd pads will wear discs a lot.

Renault very kindly make the disc and hub as a single unit to save costs during manufacture as I found out recently to my cost…

really?

Brakes aren't a place to save money.

(Especially if you have a Toyota)

If your changing the pads you might aswell do the discs too. They tend to wear more at the outer edge where the speed is fastest and get thicker as you near the center of the hub. When you put new pads on an old disc against this angled face you compromise the efficency and it dosent get any better with wear. For the cost that most manufacturers will sell a complete braking set, rather than seperate discs and pads, you might as well change the lot. For example, last time I did the Astra brakes, it was £40 for the pads, or £60 for the full set of discs and pads.

epicyclo – Member
Brakes aren't a place to save money.

That's what makes them such an easy sell for a bit of unecessary work. Bloody ford would replace my discs every week if I let them.

Good lord. I've been through sets of discs and pads in 6000 miles. 50000 is a *lot* of miles.

For what it's worth, the manufacturers publish minimum thicknesses for brake discs, and for the average vented disc they allow 1mm of wear per side – ie, a 20mm thick disc can wear to 18mm. On solid disks you sometimes get 4mm. So if you can operate a pair of calipers, you can check out what the garage is saying yourself. Same goes for pads.

Now, worn discs have two effects – less mass, so there's less to dump heat into, therefore your brakes get hotter, the pads wear faster, and they stop working sooner (ie after a few uses of the brakes on a series of bends, or during an emergency stop on the motorway – the pads start burning up, and they stop working. See the bloke who died in a Lexus). The second effect is that the increased heat cycling and force on less metal eventually leads to cracks. Cracks eventually lead to disintegration – one will inevitably go before the other, possibly resulting in a spin. Another place you do not want to go.

So the executive summary is: A 1.5mm lip suggests the disks are way past it. The results of not changing them can be catastrophic brake failure. Catastrophic brake failure can lead to death. Change the brake fluid whilst it's all being done too, as not changing that can also lead to brake failure.

Also if you let your pads wear too far, it'll screw the discs – as we found when my wifes car had its second service at 20k. I had a chat with the Service Manager and he said that the pads on these normally last 15k, especially with it been an auto…

Note to self, check discs/pads evey 10k.

tron +1

VW have minimum thickness on the pads too. Only about half the material is used.

sounds ok

I now ask for the 'old parts' to be retained and given to me BEFORE the work is done, learned the hard way …………..

Our Megane failed it's first MOT on the front disc wear, 64,000 if I remember right. Also seem to remember it was expensive! 😕

FWIW I just traded in an 06 Diesel Focus with 90k miles on the clock (all mine) and it still had the original discs & pads on all round (and it passed an MOT 3 months ago at +/- 85k on.

Mind you, about 75% of the 90k miles were on motorways which doesn't really cause brake wear if you look ahead far enough

80,000 miles here for discs and pads together.

Motorway cruising all the time though so if its a town type car 50,000 is a reasonable time to change.

Right-ho, I'll get them done (poor credit card…. 🙁 )

Thanks everyone,

Ben

A specialist independent could be a lot cheaper than a main dealer. Might be worth looking for recommendations via google for your local area and ringing round.

I paid 50% of a main dealer quote for replacing disks and pads on one car

smurf

I've just put new front pads and discs on my car (Passat) at 45k. That doesn't feel too out of line with other cars I've had and the discs were visibly lipped and pads visibly worn so not remotely surprising. Rear pads got done as well so quite an expensive service. Plus of course it would be within a month of 4 new tyres wouldn't it? Oh yes. Naturally! Poor me.

Personally I don't bother at 1.5 mm. Wait till the MOT man complains. The wear limits are very over sensitive and not an issue unless the car has thin sporty vented and drilled discs IMHO.

I've used cars with well over 70k on one set of discs. Does depend on driving style.

Think I'm on my fourth pair of front discs/pads and have done 80k. Not yet worn out pads before discs need replacing. IMO the inside of the discs get pitted due to water and the garage says to replace them. I provide the parts as I can get geniune mazda parts (or aftermarket) cheaper on line than the garage can get them. This also includes Mazda dealers who have a massive mark up on their parts as well as an inflated hourly charge.

How do you know the disk hasnt had the lip ground off in the past therefore its another 3mm wear, Unless the disks measured you wont really know! All i'l say is its your life and whoevers you take with you!!

I'm a sad act who has always got the spanners out on my Frenchie 😆 everytime the pads are changed the disks are done too, so i'm looking at every 3 years ish

DIY time I say, easy job and spend the cash saved on some new bike bits 😉

Good lord. I've been through sets of discs and pads in 6000 miles. 50000 is a *lot* of miles.

6000 miles!!! FFS what are you doing to it? Driving round with your left foot on the brake all the time? Are you one of these people that brakes for every single corner and can't back off and roll up to a junction instead of braking for every one? I'm truly dumbfounded by that….. 😯

50k a lot? Nahh.
Our last car (Which Solamanda above bought off us) had done 39k when we bought it. We replaced the OE pads just after that, then did 60k + on it (So 100k total). It was still on the same pads when we sold it, and the OE discs. Solamanda hasn't mentioned that he's replaced the discs to me yet, but I know he's done another 12k at least by now, so that's 112k on one set of dics and 2 sets of pads…..And it's a diesel Vectra estate, a fairly big heavy car.

Where and how you drive has more bearing on brake life than anything else. Motorway miles use no brakes at all, town kills them. That said, even in town it's possible to hardly use the brakes at all if you're smooth and plan ahead. It's not hard, you just have to put some thought into it. 🙂

LOL @ Peter

It's on 120k now. *goes to double check the discs*

I'm pretty sure its partly down to the engine in a car. A heavy lump diesel is easy to drive without the brakes as the engine braking slows the car down very well.

Renault very kindly make the disc and hub as a single unit to save costs during manufacture as I found out recently to my cost…

Yes they are a thoughtfull lot as i found out with our renault and the best bit was 4 different diameter discs? WTF?

I think our A4 had never had 'em replaced 'till about 150k – tho' to be fair about 140k of that was my OH doing 60 miles each way to work.

>engine braking slows the car down very well

Even my old 1.3 Escort had decent engine breaking..

You need a proper disc measuring calliper and the manufacturer's data for a definitive answer, but as a rough guide, 1.5mm per side is worn out. Replace them.

I've got 98k from new on my Passat Estate a big a heavy car and I haven't had discs or pads yet :oops

and only 2 sets of front tyres and one set of rears – I only changed the rears because of their mileage not because the tread was worn.

You must drive like Colin F&*%$£ McCrae 😀

It's over £400 for a disc and pad change all round on my car 🙁

For what it's worth the MOT man will only tell you to change the discs once they're way past it – scored or breaking up. They can't take the wheels off, so they don't measure them or even get a chance to eyeball them for being thing.

An MOT isn't at all akin to a service in terms of the level of inspection done.

6000 miles!!! FFS what are you doing to it? Driving round with your left foot on the brake all the time? Are you one of these people that brakes for every single corner and can't back off and roll up to a junction instead of braking for every one? I'm truly dumbfounded by that…..

Ford Ka, brakes were fairly marginal for the car as standard – 3 passengers in and you really had to work to stop it. That said, I was 18 and going everywhere at warp speed 9 on B roads. Occasionally upset a local bloke with an Elise… I was also getting through tyres at the same rate. Made servicing nice and easy though – oil change, tyres, discs and pads. Everything at the same time 😆

It's over £400 for a disc and pad change all round on my car

Cheap as chips. Fronts on my '91 car are 148+VAT a pair, rears are 178+VAT and pads are ~£50 per axle + VAT. Don't bother going to dealers!

Ford Focus parts. The costs used to make my eyes water, glad they were customer cars!

Cheap as chips genesis 🙂 <ouch!>

You build WRC cars?

Used to work on event and part time for a team that ran privateer GroupA and WRC cars, gave it up when it clashed too much with my work and personal life. Coolest thing we built was an RS2000Maxi