My car (FWIW:2017 Subaru Forester with auto CVT gearbox) is in for 60,000 km service and garage have just called saying front brakes are down to 15% and they need to replace pads (fair enough) AND rotors (wtf!).
This is the first time pads need replacing.
Is this now standard practice to replace pads and rotors together?
I'm sure discs wear out, but surely they should outlive one set of pads...
(Yes, we live somewhere hilly and do take the car off road in dusty conditions so the pads down to 15% doesn't surprise me)
It usually depends on how the discs have worn. If they have a substantial lip or internal corrosion, many places will want to replace them even if they aren't worn too thin.
depends on the reason for needing the discs to be replaced.
Did they say they were worn past (or near to) the minimum thickness? or are they warped or cracked.
I wouldnt have expected them to be worn down to near minimum thickness in that mileage, but if theyre warped/cracked then thats not mileage related, but is usually due to excess heat, which can occur in very short order if subject to hard stops from high speed, or towing heavy loads etc.
They didn't mention anything about lips, corrosion, warping or cracking. Only said that putting new pads on old discs can lead to more noise and vibration...
Ask the garage why the disks need changed.
It's not "standard" practice but it's often best practice especially as the garage is fairly reasonably allowed to thinkt he common majority of the population will not check their pads for another 60k....and certainly unlikely to check the disk
Only said that putting new pads on old discs can lead to more noise and vibration…
Is accurate.
putting new pads on old discs can lead to more noise and vibration…
Can... That's the key word here.
Take the wheel off and have a look yourself.
The only time I've ever replaced a rotor /disk is because I've upgraded it, not because it was knackered.
That's not to say that's the case with you. A small lip is fine and expected. If it's been stood for 6 months outside and the disk is a rusty mess.. Probably time for a new set of disks and pads.
It's not standard practice to replace rotors when pads are worn at all. But if you do live in a hilly area and are heavy on the brakes it's not inconceivable, I'd just be a little skeptical.
Eyeball the disks yourself, a photo would help. Of the vented section on the outer rim of the disk.
It's very rate to find a garage that will turn rotors. Pads never cover the entire rotor surface so there will be a lip on each edge, plus the pads and rotors bed together. Putting new pads on old rotors means the irregularaties that were matched won't be and you won't like the result. When rotors were routinely turned you could get a good enough surface to put new pads on refaced rotors.
I just replaced 8000 mile rotors because they'd developed laterl runout. Had to do the pads too, even though they had 95% thickness
Addition.. Car brakes need to be bedded in or they will sqeal and judder.
Bedding in is pretty easy.
1. Do half an hour of stop start town driving to get some heat into them.. Don't do it cold.
2. Do a series of heavy braking, maybe 5 times, find a quiet road and very carefully be aware, get up to about 60mph, and brake very hard down to about 20mph.
Not hard enough to skid or activate ABS, but pretty hard.
Do that a few times.
Car brakes need to be bedded in or they will sqeal and judder.
Never been a thing for me and I've replaced alot of ****ed disks over the years - and given that they would usually have come on used cars it can't be blamed on lack of bedding in... Usually the inside face has broken up through corrosion cracks but also seen cracks in the vents and areas where the disk had discoloured causing the pad to grip more in that area causing vibration /grabbing under braking
I always replace the discs when doing the pads on my cars, by the time the pads are worn down to 2-3mm the disc is almost guaranteed to be more than half worn. Putting new pads on would mean that the disc would wear out first, ignoring any bedding in issues, so you could see plenty of pad left but the disc could fail. I changed the pads and discs on my Fabia at 86k and the discs were 3/4 worn, same as the pads. Pads were £28 or I could get a full disc and pad kit for £80. For the extra £52 it was worth it for peace of mind.
For the cost of doing it all at the same time vs a potential crash due to a safety component failing I don't risk it.
Since Asbestos was banned from brake pads they have had to make the friction material harder and the disks softer to get the same performance. Ask people in the trade and they will suggest that most disks these days are only good for a maximum of 2 sets of pads. Add in TC and if you have ever driven in anger on mud or snow/ice then you won't be long wearing em out anyway.
The discs on our 50k miles mk7 golf were completely fisted after 1 previous pad change. I changed both out as their really not that expensive.
Anecdotal evidence but I took my car to main stealer for 2 year service on a supposed fixed price deal. They said they need to replace the pads and disks for xxx, no idea what. Anyway, I smelt a rat so took it to my indie who said they were trying to pull my pants down.
I think it was fluid too, it was stupid money like 500 quid. Anyway, indie did the pads only. I drive like a pensioner but live at the top of a hill.
Back in the day I used to get 10k out of the discs on my Ka - but I treated like a go cart, flat out into every corner, hard on the brakes, hard on the power. Lots of fun without braking the speed limit as it was so gutless.
I'm grown up now so I hardly touch the brakes. A3 had the discs replaced at 110k.
What welshfarmer said - except I might be wrong but I thought it was the other way round; the pads are softer because they don't have asbestos, so any rust on the disc isn't always cleaned off fully and wears a little depression in the pad, which allows more corrosion, so by the time the pads are worn out they're not flat any more and nor is the disc. Happens particularly if you are light on the brakes and keep the car outside.
I’ve just put new front discs and pads on my forester at 78k miles.
It had brand new rears fitted @52k miles when I bought it, theey were so new they hadn’t even been bedded in.
I’ll guess that the fronts had been replaced before this, as they were already lightly worn.
So a forester needing new discs at 43k miles doesn’t seem unusual to me.
My 2p, I always replace discs and pads as one.
They are safety critical, and truthfully not that expensive.
For reference my VW front rotors have done 116K/ second set of pads fitted at 45k - upgrade. Rears were replaced at 102K
Just bought some discs for my old BMW and was suprised to see the marking on the discs showing wear minimum was only about 2mm or 3 mm from new discs !! As said brake material has changed now and is more aggresive to discs . Depends on how you drive and where you drive. More motorway distances will use the brakes less and more town and hilly, more. I remember a mate having a scooby sti wrx and the discs would crack and warp more than he filled it with fuel, so wonder if the forrester has small brakes also , which may increase brake wear.
Hmmm, I've given the go-ahead to replace pads and rotors on the front. They tell me the rears have 30% life left so I guess I'll be getting those replaced next time. Ho hum...
I have no idea how much P&L I'd save by just replacing the pads but the cost of pads and rotors is $537 CAD (so around £318) and that's at an indie not using OEM parts