Brake Discs

[Chris81]

A few months ago my dealer brought my front brake discs to my attention for being pitted. They look fine from the outer facing surface, but the inner face of the discs is 'pitted'. I've had a feel/look and there are a few thick rust rings on the inner face of both discs, though braking performance seems the same as it always was. Didnt get them done at the time but as service time beckons I'm considering it. Had them skimmed once and they can't skim again as discs are too thin. A few questions...

1. How much should the dealer charge me to supply and fit new discs?

2. Will I also need new pads? There's plently life in the existing ones but I suspect the inner pad will have been ruined by the rust rings in the disc.

3. What causes the inner faces to pit but the outer ones to be fine? I use the car daily and make use of the brakes (!) so it's not as if the car is sitting around idle for long periods?

4. Do you think they definitely need doing? Like I say, brakes seem as effective as they always were.

5. As part of the MOT test, does the garage carry out a braking performance test on the rollers?

[alfiejts]

I got a new set of discs and pads from my local trade motor factors for my old Yaris and they only cost about £50 for everying. Easy to change yourself with a few tools...

Assume 30 mins labour as well, if you're paying a garage, so you shouldn't be payin gmore than £100 all in fitted I'd say...

[Madasafish]

1. How much should the dealer charge me to supply and fit new discs?

IF it's a Toyota dealer : pads and disks c £150 plus labour.. is my estimate.. Non Toyota parts c £100.. The quoted £50 for pads and disks above ... well lets put it like this.. I bet they are an unknown brand and I would NOT put my life at risk...

2. Will I also need new pads? There's plently life in the existing ones but I suspect the inner pad will have been ruined by the rust rings in the disc.

New disks meqan new pads. Period. Every time...

3. What causes the inner faces to pit but the outer ones to be fine? I use the car daily and make use of the brakes (!) so it's not as if the car is sitting around idle for long periods?

Water from the wheels .. and stopping and leaving the car when disks are wet. Sometimes calipers do not move freely on slides giving uneven wear..

4. Do you think they definitely need doing? Like I say, brakes seem as effective as they always were.

Hmm.. Difficult to say. Wife's 106 had light pitting as you describe 8 years ago: I just drive it once a month and brake very hard down our steep hill.. Still OK...

5. As part of the MOT test, does the garage carry out a braking performance test on the rollers?

Yes.. How else can they test them..?

Note: advisories in the MOT are just that...Advice...

[Chris81]

Cheers for the advice. I suspect at least £200 inc VAT and labour at a dealers is about right . Motor factors cheaper but I don't trust myself doing the job. Maybe a compromise is getting a decent independent to quote for the work but think I'll see how they perform on the MOT first. The t-sport brakes have never been that great IMHO and I've had the car from new. Even when I had them re-skimmed and new pads fitted a couple of years back it didn't seem to improve braking performance. Funnily enough I've driven an old 1.0 Yaris and the brakes felt way better on that which is strange as the t-sport has discs all round.

[Raeman]

I got my new discs & pads from Toyota when i did mine last year.

Cost quite a bit more than buying from the motor factors, but i allways use the best i can when it comes to brakes.

I also inspected and cleaned out the rear drums when i changed mine, the result was/still is brilliant braking.

Think it cost me about £100 for the discs and about £50 for the pads but i'm glad i got the proper ones.

[Chris81]

Well it had its MOT and passed, but got an Advisory Note for 'both front brake discs heavily corroded on inner face'.

Just wondered how much of these the tetser can actually see through the little gap in the back of the brake disc guard. I've had a feel and there are definitely a few thick circles of rust on the inner faces. The outer faces are absolutely fine. Obviously the car passed the brake roller test ok and I have to say the feel from the brakes is the same as it always was (same as when discs were new, same as when I had them skimmed). There's no drop off in performance, in fact if anything they feel slightly better than they once were. Loads of life left in the pads as I had new ones on about 15k ago when the discs were skimmed. I've no problem in spending the cash and getting new discs and pads fitted if necessary, but given that the brakes feel fine it seems a waste. I'm guessing they get gradually worse rather than just fail one day?

The advisory note is also an excercise in @rse covering. It says how you can be liable for prosecution, invalidate insurance etc etc if these things are not attended to. Does anyone know of anyone who has ever been prosecuted or had an insurance claim voided for failing to take the testers advice? Surely it's either safe or it isn't. There should really be no middle ground.

[Madasafish]

Well it had its MOT and passed, but got an Advisory Note for 'both front brake discs heavily corroded on inner face'.

I'm guessing they get gradually worse rather than just fail one day?

Just brake HARD once a fortnight and they will be fine.. and the day they are not, change them

The advisory note is also an excercise in @rse covering. It says how you can be liable for prosecution, invalidate insurance etc etc if these things are not attended to. Does anyone know of anyone who has ever been prosecuted or had an insurance claim voided for failing to take the testers advice? Surely it's either safe or it isn't. There should really be no middle ground.

Bull**** baffles brains...

[minidoughty]

i allways use the best i can when it comes to brakes.

why didn't you get 3G discs then? or ferodo/endless/project mu etc. pads? All of which are better quality and perform better than the standard toyota ones?

[Parts-King]

Surely it's either safe or it isn't. There should really be no middle ground.

If only life was that simple!

I would think it unlikely anybody has been prosecuted, yes there is an amount of rrr's covering, but there are drivers out there who take not a blind bit of good advice and only have work done on their cars when it either fails the MOT or breaks down and it cannot be driven. There is a bit of a misconception over MOT work, most people think it is black and white, pass or fail, but that is not the case. You could quite easily have brakes worn down to the limit, working perfectly well, pass the MOT with an advisory only to fail completely a week or two later! (para phrasing a situation here but you get the drift) The conversation then goes something like "Well it only passed the MOT last week" thereby inferring something was done on the MOT that caused the brakes to fail. An advisory is just that, advice and an opinion that work will need doing at some time in the future

Kingo

[minidoughty]

I agree, just change your brakes already...

If the discs need doing anyway, may aswell have the pads changed at the same time.

[Raeman]

i allways use the best i can when it comes to brakes.

why didn't you get 3G discs then? or ferodo/endless/project mu etc. pads? All of which are better quality and perform better than the standard toyota ones?

Because for a 10yr old 1.3 Yaris, the standard Toyota ones are more than capable of doing the job to stop the thing.

I used to be in the VW scene years ago and remember spending silly money on a set of drilled discs and fancy pads only to make the car look better. The performance was the same at normal driving as the standard ones so total waste of money.

[Chris81]

Just to follow up this thread, 8 months have passed and I haven't yet replaced the discs. However I had a good feel of the inner faces of the front discs again and they've got a lot worse. There's literally an inch at the topmost of one disc which isn't been swept at all by the pad as it's just thick rust. I've decided to get them replaced now, however what's causing the problem in the first place, as I worry I could just get the new parts fitted then it could re-occur. The brakes do get plenty use so I can't understand it, and the car never gets left for more than a day at a time. Brake performance is still the same. Could it be a sticky caliper maybe? Any other potential causes?

And another question while we're talking brakes... Has anyone ever replaced the disc guards/hub plates - whatever you call them. Mine are excessively rusty - when feeling found the back of the disc there were big flakes of paint/rust coming off these guards.

[Chris81]

To follow up this thread in case anyone comes back to it, I had new discs and pads fitted by Toyota, at a cost of £220 fitted - that price included a small discount. Not too bad for genuine parts, especially given the prices they're going for on eBay.

[Captain Scarlet]

I also regularly get an MOT advisory about the front brake disks being (in my case) slightly pitted on the inner face. Outer appearance is fine and so is performance, although I am puzzled how the inner faces can be seen without swinging the caliper out of the way. Mine is an 02 T-Sport which I have owned for about 6 years.

The reason why they are corroded is because the inner pad is not moving properly (or maybe at all) on the caliper guides, leaving areas of rust where insufficient contact is being made with the disk. This is a common fault with this type of caliper design and not specific to make or model. The guides get clogged with brake dust and crud from the road over time preventing full movement of the pad. This is likely to be exacerbated if the pad is not exactly the right size which is often the case with aftermarket pads. (My disks and pads are OE) In the worst case scenario the guides could be seized in the caliper but presumably in your case the garage checked this when putting in the new disks and pads. At the same time they should have cleaned off all the debris restricting free movement and lightly smeared the guides with copper grease.

Do you notice a significant improvement in the braking performance now?

[Cyker]

Yeah, sounds like the inner caliper isn't clamping properly/flatly