Rear brake disc corrosion....

[Lawnmowerman]

Run-out 2018 Hybrid Design.

Following on from my post regarding the rear suspension, it was reported at the service (2 years - 16.5K miles) that the rear discs were corroding and required renewal. Corrosion was noted at 1 year old and 9.5k miles. They have now deteriorated further.

Light corrosion on front discs and a reported wear of 20% - 25% wear on front pads. Rear pad wear 10% - 15% and heavier corrosion. 

My days of driving spiritedly have long gone and prefer a much calmer side to my driving hence the low pad wear rate. However, surely this suggests that the pad material used (particularly rears) is an incorrect choice hence the corrosion of the discs to the point of renewal.

I have no desire to have to replace brakes as frequently as this and wonder if anyone has had a similar experience?

Many thanks.

LMM 😊

 

 

[Avalon]

It depends where the corrosion is taking place and how bad, a photo would really help. In general the swept areas would stay clean with use, the edge may lip/corrode if the pad doesn’t sweep all the way to the outer edge. That said, if for example you live by the sea etc. that may play a factor. A decent independent factor should be significantly cheaper than Toyota if it comes down to it.

[Lawnmowerman]

Corrosion across whole disc - the outer edge is normal. It is the contact area that is the concern. Don't live on the coast.

My post was to see if this was prevalent or not. Thanks for your reply

[PeteB]

Your mileage doesn't seem desperately low, do you have lots of days where the car isn't used?

In my experience Toyota brakes seem to like daily use.  Brake wear has been minimal on 7 Prius I owned since 2002, covering over 330,000 miles between them, even though the cars were not garaged.  What they hate is infrequent use, where a cycle of rust/wear, rust/wear can eat the discs and pads in just 10,000 miles or less!  I found this to my cost with a Gen 1 Prius - at 70k, hardly any wear.  I then only drove it once every one or two weeks, and then mostly short distances for a year, while I had use of a company Prius.  I needed new discs/pads all round very soon after.  I used the car daily again for the remaining 4 years I owned it, and when sold the new brakes had done about 70k and were still hardly worn.  I've heard of cars being sold at over 100k with original discs/pads still in place.

At 60,000 miles, my Gen 3 Prius (2012-2016) had used about ¼ of the pad thickness, so I wouldn't have expected any brake maintenance for a very long time.  My Gen 4 Prius (2016-2019) had 39,000 miles on the clock (exactly - to the mile!) when I traded it for my RAV4, and again brake wear was minimal.

I brake gently too, using the HSI to achieve good regen without resorting to assistance from the friction materials.  I also lift off the accelerator early where possible when approaching roundabouts, speed limit changes etc to try to minimise brake use.

In the early noughties, Toyota routinely replaced rusty discs (including mine that one time) under warranty, but after that they fixed the problem by changing the warranty to exclude them!  A shame they didn't fix the mix of metals in the disc instead, which I suspect more than the pad compound.

[Lawnmowerman]

6 minutes ago, PeteB said:

Your mileage doesn't seem desperately low, do you have lots of days where the car isn't used?

In my experience Toyota brakes seem to like daily use.  Brake wear has been minimal on 7 Prius I owned since 2002, covering over 330,000 miles between them, even though the cars were not garaged.  What they hate is infrequent use, where a cycle of rust/wear, rust/wear can eat the discs and pads in just 10,000 miles or less!  I found this to my cost with a Gen 1 Prius - at 70k, hardly any wear.  I then only drove it once every one or two weeks, and then mostly short distances for a year, while I had use of a company Prius.  I needed new discs/pads all round very soon after.  I used the car daily again for the remaining 4 years I owned it, and when sold the new brakes had done about 70k and were still hardly worn.  I've heard of cars being sold at over 100k with original discs/pads still in place.

At 60,000 miles, my Gen 3 Prius (2012-2016) had used about ¼ of the pad thickness, so I wouldn't have expected any brake maintenance for a very long time.  My Gen 4 Prius (2016-2019) had 39,000 miles on the clock (exactly - to the mile!) when I traded it for my RAV4, and again brake wear was minimal.

I brake gently too, using the HSI to achieve good regen without resorting to assistance from the friction materials.  I also lift off the accelerator early where possible when approaching roundabouts, speed limit changes etc to try to minimise brake use.

In the early noughties, Toyota routinely replaced rusty discs (including mine that one time) under warranty, but after that they fixed the problem by changing the warranty to exclude them!  A shame they didn't fix the mix of metals in the disc instead, which I suspect more than the pad compound.

No, it's used regularly. 14 miles (part dual carriageway) in the morning and the return in the evening.

Going back MANY years I remember when the discs could outlast the pads by a factor of three (the cars that had discs 😊). Then they thought it a better idea to remove the asbestos (not good to kill the mechanics) and used sintered metal in place - goodbye long-life discs.

 

[PeteB]

A Vauxhall Nova I bought new in 1984 and sold 14 years later with 93k on the clock still had original discs, pads, shoes and drums (and clutch)!

I'm sure if they used more stainless steel and/or other corrosion resistant materials in the discs it would help.  If they didn't rust, they wouldn't eat the pads so much.

[Lawnmowerman]

Asked Toyota Customer support for assistance. Basically said on yer bike (at least its brakes are good!).

Was told that none of Customer Support are technical - he said they relied on the dealers for technical advice (what!). So asked if it could be escalated to a technically qualified manager. That was three weeks ago - no reply, nothing!

Have written a letter (old-fashioned) to the new President and MD of Toyota GB (1st September) Agustin Martin asking for his intervention. Sent first class and signed for.

To have your correspondence ignored is the worst case of customer support imaginable. Didn't expect that of Toyota.

 

LMM 🙄

 

[FROSTYBALLS]

Most manufacturers now only warranty discs for six months as they're seen as consumables. 

The son of our neighbour had a 2011 Polo from new. At the 12 month service the discs needed replacing through being blued - overheated. VW replaced the discs under goodwill even though they were only covered for six months under the new car warranty. The second service the discs were again blued, but this time the customer had to pay for replacement. Their two new Polos since have been OK.

[Lawnmowerman]

Received e-mail on behalf of Agustin Martin and as expected they aren't interested in the corroded brakes.  Won't repeat myself - very disappointed in the quality (oops - just have).

However, they did shed some light on the rear trailing arm bushes - will update that thread.

LMM 😊