when to change brakes

[dbird]

this may sound really stupid but..... how do I know when to change my discs and pads??

 

[maggi200]

Before the NEED changing. Unfortunately in this country, much like tyres, they become a 'distress purchase'.

I'm not sure on the tolerances off the top of my head but tbh it's gonna be obvious. The disc you'll have a visual look over and the lip will tell you if they need doing, if it's going to soon but not yet and you need new pads, do it anyway, cos you'll only have to replace the pads again anyway.

For the pads, you can see how much meat is left through the caliper. Again, it'll be obvious.

 

[dbird]

thank youuu

 

[singlespeed]

The measurements are in here>> https://www.twingo133.net/technical-and-paint-information/twingo-renaultsport-maintenace-t371.html

As Maggi said, they are often neglected untill they start to make a noise.
Theres no wear indicators, so a visual inspection is needed. If your light on the brakes and they don't wear down from being used hard, then the pads seizing in the carrier or, the caliper guide pins/sliders seizing up is a possibility. If you have a bit of time and the tools required, then a strip down and clean once a year is a good idea as it can save the hastle of having to get it fixed when its gone wrong... which will never be at a convenient time.

Theres a picture guide in the how to section for stripping down the fronts.



Mine were stripped and cleaned yesterday as I was swapping wheels over

 

[maggi200]

Carries made 50k until they needed changing, and even the rears only needed doing because a caliper seized and decided to grind the pad down to near metal quite rapidly.

 

[oscar]

basically everything that neil said! you'll need a micrometer for measuring disc thickness, steel rule for measuring pad thickness and some emri paper / sand paper for cleaning up the caliper carrier and caliper itself of dirt of grime / rust. some copper grease is a good thing to have here also so that you can apply some more to help prevent any squeeking on the caliper carrier and to prevent seizing on it. use the link that neil provided you with to compare your measurements too and you'll be good to go from now on doing your own brakes.


one other way to recognise that your brakes may need changing without stripping them down would be that your brake fluid level may look a bit low which means your caliper pistons are sitting out further than they should to take up the wear in your pads.

 

[dbird]

got it, I will probs do the basic looking over seeing as I am a student and so have a lack of money, space and time for tools and proper maintenance work.

Thanks for the info!

 

[MovingShadow]

My front brakes were worn on the 60k kilometer service.

 

[oscar]

My front brakes were worn on the 60k kilometer service.

seems about right man, depends on the compound used and the driver in question. some people use a lot of engine braking whilst others brake harder than others with their foot. taxi drivers are the worst culprates!

 

[MovingShadow]

I use alot of breaking on the engine and I try to anticipate. My home - work travelling is usually driving like a grandmother :-D

 

[the_notorious_C_A_T]

I skinned mine in 16k miles. I hardly drive like a maniac either :-(

 

[Ollie133cup]

Well , after my cars been sitting for a year and half. Ive decided to change mine, still plenty of meat on the old pads as they have only done ~14k miles.

 

[dbird]

anyone recommend any specific websites / brake companies to buy from?

 

[MovingShadow]

anyone recommend any specific websites / brake companies to buy from?

https://www.kamracing.co.uk/car-tuning/renault/renault-twingo.html

 

[dbird]

So I have a definite lip in my disc that my finger nail gets stuck on as shown In photo but my pads have plenty of meat, what should I do ? Replace all of it pads and discs?

 

[oscar]

BRAKE DISC / PAD DIMENSIONS AND TORQUES
Front brakes:-
Front disc diameter 280mm
Minimum Disc Thickness For Replacement / Ventilated Front : 21,8 mm
Disc Runout Front : 0,03mm
Minimum Pad Thickness Front : 8,2 mm (measurements include lining and pad backing plate)
Front disc bolts : 14N.m
Front guide pin bolts : 35 N.m
Front caliper support bolts : 100 N.m

Rear Brakes:-
Rear disc diameter 240mm
Minimum Disc Thickness For Replacement Rear : 7,0 mm
Disc Runout Rear : 0,06mm
Minimum Pad Thickness Rear : 6,0 mm (measurements include lining and pad backing plate)
Rear disc nut : 175 N.m
Rear guide pin bolts : 32 N.m
Rear caliper support bolts : 105 N.m

technical-and-paint-information/twingo-renaultsport-maintenace-t371.html

that lip is normal, that's the basic wear pattern of discs. being made from cast iron, it's only normal that the contact area between the pad and disc is always shiny and renewed upon every application of the brake pedal.

for future reference, to measure your brake discs for thickness and adhering to renaults above service requirements you will require :

external micrometer - 0-25mm
and that's your whack! this will measure the thickness of the remaining disc, so that you can always keep an eye on the thickness. it will also measure the thickness of your brake pads
in the shop we'd usually use an angle grinder or a bench grinder to smooth out the lip but it's really not required as it's doing no harm. take a file to it if you have one, you can also remove the discs and hammer the circumference face of the discs and give the lips a good tap... the rust and lip should fall off, then file the rest down to cure your OCD compulsions.


another oscar essay! lol

 

[dbird]

Haha oscar you are one of the most helpful guys on here! I'll buy a micrometer as I get worried about braking etc.... I painted my brake calipers today so I also wire brushed down the exterior of the rusty discs.... ALOT came off!

 

[oscar]

calibrate the micrometer by lining the 0 indicator up with the 0 black line on the micrometer and then twist it open till you get it on the pad and then slowly tighten it until you feel the tiniest of the tiniest resistance developing ; that'll be your measurement, like this for your pads (below)

this is how to read the micrometer just incase you get confused, this would read as 14.28 / 14.29 mm (or maybe it's 15, i can't clearly see if it's over the 14 or into the 15 ... but you should get the idea)

i wouldn't go down to the minimum before you change though. a good rule of thumb is to add on 1mm / 2mm on top of the official figure for vented discs and 1mm for the rear single solid type discs,

your calipers look like a good job man!

 

[dbird]

Thanks man I'll give it a go!

 

[singlespeed]

That's 14.29

Clearly 10 on the fixed scale, plus four marks showing... 14.xx
The rotating dial has 100 divisions per revolution. With the line against the 29mark, denoting 29/100ths of a mm
14.29mm

With nothing in the micrometer, and it closed up fully, the rotating zero should line up, denoting 0.00mm. If that's out then the above measurement will also be out. So, worth a check before and after each use.