How can you tell if brake pads & discs are worn out?

How can you tell if brake pads & discs are worn out?

Author
Discussion

jimmyb

12,254 posts

197 months

Thursday 16th July 2009
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Apparently aygos have a wear indicator on them so when braking if time to change they will squeal and squeak. Aygos apparently have an issue with discs and pads and it seems that on the aygo owners forum they recommend not using toyota pads and disks as the toyota supplied disks wear quite fast.

http://toyotaownersclub.com/forums/index.php?s=12a...

stephen300o

15,464 posts

209 months

Thursday 16th July 2009
quotequote all
jimmyb said:
Apparently aygos have a wear indicator on them so when braking if time to change they will squeal and squeak. Aygos apparently have an issue with discs and pads and it seems that on the aygo owners forum they recommend not using toyota pads and disks as the toyota supplied disks wear quite fast.

http://toyotaownersclub.com/forums/index.php?s=12a...
Similar to Jeep then, the oem discs are a joke, they warp badly. My dads discs lasted a couple of months, so went to patern parts and had no trouble.

Dogwatch

5,949 posts

203 months

Thursday 16th July 2009
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If your toolkit doesn't run to micrometers and other scientific measuring equipment a 5 mm drill shank held against the pad material in-situ will give you a quick guide to how much material is left. Much below this thickness is time for a change.
Be sure no grease or oil is inadvertently allowed on the disc during your investigations!

Mr_Yogi

Original Poster:

3,265 posts

236 months

Saturday 25th July 2009
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Just thought I'd update this thread.

Took a look at the rims with the wheels still on, and there were very deep groves on them, both sides of each disc. After reading the above links regarding chocolate brake discs, and couldn't find any alternatives which were unanimously agreed on as being better, I prepared to bend over and take the main dealer offer.

However when I came to pay for the work, without even complaining about the short disc life, they had done them under warrantee thumbup

I've had a few problems with my Aygo but the dealer has always been very good thumbup

I'm so glad I went for the Aygo over the 107 or C1, having had previous experience of the Peugeot main dealers.


Edited by Mr_Yogi on Saturday 25th July 21:00

rsv gone!

11,286 posts

222 months

Saturday 25th July 2009
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tinman0 said:
Mr_Yogi said:
The garage has said both front discs and pads need replacing, however alarm bells started ringing when the phrase "your pads are 95% worn" was used, something I read on here years ago.
Garage has a lack of work on. Hence you needing new discs.
yes They are always quick to suggest a brake change.

The dealer I took my Evo to recommended I changed my pads as 'there's only a couple of thousand miles left in them.'

The car did another 9000 miles (two services) before they needed to be changed.

Drive Blind

4,623 posts

158 months

Saturday 25th July 2009
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slightly OT, but is it just me or are discs being made out of softer metal or is it the pads getting harder?

I've been driving nearly 20 years and until recently discs would last 2 or 3 sets of pads. Now it's discs and pads at the same time and they only last about 20K miles. BTW i'm not taking a dealers word for my discs needing replaced I can see the wear myself and feel the reduced braking performance.

Discussing this with my dad he recalls when you rarely ever changed discs. They would last forever.

What's the cause? Change of materials, heavier cars, dealers spotting an easy way to make money at service time?

WhoseGeneration

4,090 posts

188 months

Saturday 25th July 2009
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Drive Blind said:
slightly OT, but is it just me or are discs being made out of softer metal or is it the pads getting harder?

I've been driving nearly 20 years and until recently discs would last 2 or 3 sets of pads. Now it's discs and pads at the same time and they only last about 20K miles. BTW i'm not taking a dealers word for my discs needing replaced I can see the wear myself and feel the reduced braking performance.

Discussing this with my dad he recalls when you rarely ever changed discs. They would last forever.

What's the cause? Change of materials, heavier cars, dealers spotting an easy way to make money at service time?
Generally thought to be the result of the banning of asbestos as a part of pad material.
I've been driving over 40 years and your and your dad's observations are correct.

triggersbroom

2,360 posts

185 months

Saturday 25th July 2009
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Correct. They now use a metallic compound in the pads - hence the increase in disk wear nowadays.

BTW - I almost always have found the inner pads wear more than the outer, so beware! Looking at the outers alone doesn't always tell you the full story!

keithton

13,229 posts

161 months

Sunday 26th July 2009
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i was told that mine had only 10% left 20k ago. The car has now done 46K on the origional disks and pads. They will likely stay until about 55K or when they start to go, and even then i will only change the pad's. The disks can be changed at 100k.

On another note, two origional tyres are still on the car, the fronts changed at 18K and then rears swapped to front at 35K when they still had a good 6mm left. Now at the 46 they are on about 2-3. Again shouldn't need to be replaced until atleast 50K. Not bad going in my book.

Pinger23

104 posts

206 months

Sunday 26th July 2009
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Ford dealer said my pads & disks needed changing at 35k.
Next year service at 42k asked about the disks & pads - same guy! - no problems ...

Rich_W

12,548 posts

193 months

Sunday 26th July 2009
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Can I just pooint out that brake pad/disc wear is (should be) only ever an estimate. Tjhe person examining the car has NO idea how you drive. You oculd be Schumacher or you could be a little old lady. All they can do is say how mich percentage is left on the pads. And then give a estamte as to how many miles that will last. So if a set of pads will normally last 20-30K. Then 30% left gives around 7-9K miles left. Which in most cases is less than the time to the next service.

You'd all be moaning if they didn't tell you and 5K later you went metal to metal, needing new discs as well (which may have happened with the OP)

Talksteer

4,154 posts

214 months

Sunday 26th July 2009
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The Wookie said:
hehe

Well if you're comfortable getting the wheel off, you're 80% of the way to changing the pads, it really is an easy job that dealers love charging lots for. Changing discs requires minimal effort on top.
Depends on your car, on a Fiat Coupe you have 4 pot Brembos, this is the sequence:

Take off wheel
Leaver out pad retainers
Use g-clamp to retract pads
Pads still won't move use a combination of a drift and a screw driver as a leaver plus swearing to get pads out.
Remove bolts securing disc
Try to remove calliper, apply 16st to end of socket wrench (me) fail to move bolt
Go out in other car to buy longer wrench.
Apply ridiculous force and several litres of boiling water to free bolt
Take off disc
Watch as brake line crumbles in front of you due to corrosion
Realise that as garage closed at 12:30 I won't be able to get a new one until tuesday.
What car piss out all it brake fluid
Watch it rain every evening till next weekend (I need a garage)
put it all back together again
Bleed litres of brake fluid back through the calliper until bubble stop coming out.

Simples


Ranger 6

6,694 posts

230 months

Monday 27th July 2009
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GaryST220 said:
Ranger 6 said:
I thought they were there for balancing.
Nope, when the outer edge (raised part) comes close to/wears into the machined (inner & lower part) then the discs need replacing. If like those in the picture it's roughly half and half then you can estimate with the pad wear rate as to whether you can fit another set of pads before the disc is too far gone.

Using this method I told the dealer when fitting pads that I only wanted pads fitting and not to try it on as I'd checked the discs - suprisingly enough they agreed smile