Life of Yaris brake discs?

[MikeSh]

5 hours ago, Toymo10 said:

The fact that it never happens on nearside implies a disc/pad/caliper issue perhaps.

Is the car usually left with the offside more exposed to the weather? Given the time of year, and possibly your location (salt?), it might just be the elements attacking that side more.

[Stevie J]

My car has 34K miles on it and had the pads replaced about 1500 miles ago when I noticed the pads looked a bit thin, I had them done on a service and it was said to me that they recommended the discs be changed as well, but as it only had about 32K miles on it at that time, I said just do the pads for now, as I would have expected the discs to last longer than just 32K miles.

Last week I did look at the brakes as I was inflating all the tyres before the cold weather sets in and the TPMS light starts coming on, and I did notice there was a fair sized lip around the edges of the discs on the front, not hugely worn, but worn nevertheless, so I was quite surprised about it for such a low mileage.

It will no doubt be checked and either failed or advised on the MOT next month.

What does concern me more is the fact the biting point on the clutch is now right at the top of the pedal, and it would seem that at just 34K miles, it is on the verge of needing a clutch replacement. It still bites and can do a standing start from an uphill incline, but it is tiring on the leg to have to keep raising the clutch pedal so high before getting engagement, and if gets any worse I wont be able to do a hill start. I have had works vans in the past I got when brand new, drove them through over 120K miles, and they were still on the same original clutch. For this Yaris to be needing a new clutch so soon is very disappointing. I have never ever had to replace a clutch on a car with such a low mileage. I gather Aygo's are the same and have very short lives on their clutches too, with failures often occuring by 40K miles.

To be hearing wheel bearings failing at less than 30K miles on Mk3 Yaris's is also pretty concerning, but I think a lot of that could be down to the poor state of the roads, with pot hole damage rife.

As my car is one of the earliest to be fitted with TPMS sensors, I am also expecting these to start failing soon with expired batteries, and these are not cheap to replace either.

I do feel that this Yaris may well be my last one, as I am not very happy with the clutch - it makes driving it an absolute pain, and a looming large bill for repair - at less than 35K miles.

[anchorman]

Modern pads don’t contain asbestos and contrary to popular belief, they don’t contain Kevlar (which is way too expensive).  They tend to use steel wool as a base fibre material and they sometimes contain Rockwool or similar product.   You can get different grades and some of the less pure can contain a particle of shot.  It honestly doesn’t harm but it can cause a groove.  Odd bits of roadbourne debris come and go so you might not find it after it left a groove in the disc.  Photos are always helpful in this kind of topic.  

[Cyker]

A lot of them use the same materials as clutch discs these days supposedly, which does include chopped up 'aramid fibres' (Essentially 'legally-distinct-kevlar' which is a similar material but much cheaper and isn't subject to you getting sued by DuPont)

 

If you are doing lots of stop-start traffic and hill starts, that will impact the life of the clutch a lot - Even in my diesel Yaris I could wear out the clutch in 30-40k easily and those tended to have beefier clutches than the petrols, and this is with my very coasty driving style too!

 

1-sided break wear is usually a stuck or sticky caliper, maybe the pin or debris in the pad. Could also be a fluid or brake line issue but that's rarer. Dealers often not great at diagnosing such things as they tend to just replace parts rather than check first as they get rushed through all the jobs by the higher ups.

[Toymo10]

"1-sided break wear is usually a stuck or sticky caliper, maybe the pin or debris in the pad. Could also be a fluid or brake line issue but that's rarer. Dealers often not great at diagnosing such things as they tend to just replace parts rather than check first as they get rushed through all the jobs by the higher ups."

This is my consideration too but I would not expect this on a new car ie ungreased pins and a stuck caliper. I don't have a huge confidence with the level of customer support with Toyota and  agree with your point about swapping the part option without considering the technical perspective fully.

From my previous post I considered what has been mentioned earlier ie driving and braking style and the time of year. I always drive with economy in mind and also brake gently and let the car bring itself to a stop without braking hard last minute. So with that in mind Ive tried heavier last minute braking which has cleaned up the disc overall but has not removed the  the deeper scoring. I dont like driving in this way so that won't continue. It was just a test.

Im beginning to think that the technology being so good on these cars is actually causing premature scoring on the disc but I will pursue a more meaningful conversation with the service dept when I go in and see what they say.

What I don't want to be doing is changing discs and pads after 3 years for unnecessary scoring as opposed to high mileage wear ( which I fully accept) as it fails the MOT. At my expense I might add.

 

[Derek.w]

I strip my brakes down every other year so missed it out this year it still passed it mot.

If I have a large lip on the brake disk then if thickness is within limits I grind this back

it aids removal next time.

[TonyHSD]

The problem comes from regen braking  and as a result the actual brakes rarely gets over 30C° even after hours of driving, this is very good for overall wear on the pads and discs but terribly bad for the callipers and slider pins.
In uk due to the rain, moisture in air and salt during winter the brake parts and particularly the slider pins and callipers gets water that stands on them and because these never gets hot enough the water can’t evaporate and finds it’s way through the rubber boots on both slider pins and into the piston of the calliper on each wheel. With the time these metal parts gets corroded and pistons get stuck and slider pins gets stuck too and this will preven the pads to properly move and put equal pressure which leads to uneven wear and pitted discs surfaces. 
There is no other way around except regular moderate to progressive slow downs or slow downs in N. 
As preventative maintenance really good thing is every two years to dismantle all brake parts , clean thoroughly, inspect pins if pitted replace them and live them with silicone grease but not too much and put all back together, replace brake fluid and you will have clean and shiny discs and properly working brake system, and brake parts that will last ages. 

[Derek.w]

On 11/5/2024 at 11:13 PM, TonyHSD said:

The problem comes from regen braking  and as a result the actual brakes rarely gets over 30C° even after hours of driving, this is very good for overall wear on the pads and discs but terribly bad for the callipers and slider pins.
In uk due to the rain, moisture in air and salt during winter the brake parts and particularly the slider pins and callipers gets water that stands on them and because these never gets hot enough the water can’t evaporate and finds it’s way through the rubber boots on both slider pins and into the piston of the calliper on each wheel. With the time these metal parts gets corroded and pistons get stuck and slider pins gets stuck too and this will preven the pads to properly move and put equal pressure which leads to uneven wear and pitted discs surfaces. 
There is no other way around except regular moderate to progressive slow downs or slow downs in N. 
As preventative maintenance really good thing is every two years to dismantle all brake parts , clean thoroughly, inspect pins if pitted replace them and live them with silicone grease but not too much and put all back together, replace brake fluid and you will have clean and shiny discs and properly working brake system, and brake parts that will last ages. 

For cars without regen braking still strip them down every 2 years.

[TonyHSD]

3 hours ago, Derek.w said:

For cars without regen braking still strip them down every 2 years.

That’s a good practice indeed. 👍