Baking contaminated brake pads – myth or not???

So, Nigella recommends 30 minutes at 200oC.

Question is, does it work, and if so, is it safe?

I used to just give them a good blast with the blow torch 🙂 Just do it in stages and when they stop smoking theres no oil left. The trick is to not overheat them so the friction material falls off the backing !!

The million dollar question is normal oven or fan assisted?

Yes it works, I always just heat them with a blow torch or oxy acetylene until the paint starts look slightly singed. What do you think is unsafe about heating something that’s designed to get hot?

Our oven is likely to add oil rather than take it away.  Plumbers blowtorch is the thing, a really useful piece of kit to have anyway if you don’t already, it’ll crisp up your Creme Brulee and do plumbing as well.

They will never be the same again the material is porous and will absorb oil. The pad material is also unlikely to be designed to cope with the heat of the blow torch.

You cant ever sweat all the oil out and the pads will be compromised

Bin them at £12 for 3/4 sets of cheap pads why bother.

I thought it couldn’t possibly work. Then I tried it and it did. About twenty minute at 180.

It’s worked for me for mildly contaminated pads, but a recent case of pads liberally squirted with hydraulic fluid (don’t ask) didn’t work, so new pads time.

I’d say give it a try – doesn’t take much time and effort, but as above pads are pretty cheap. Do remember to degrease the discs first though !

Muc Off works quite nicely for me, but then I have Hope brakes so contamination is brake fluid based not oil.

You could also try dishwasher.

north country boy – the working temp of a disc brake pad is a few hundred degrees c  Much hotter than an oven

I have burnt / baked disc pads a few times.  Once it then fell off the backing but a few times it worked

A few times it worked!

steering and brakes are things that need to work properly all the time.

Yup – and you can easily tell if it worked or not.  Its standard practise to burn off superficial contamination but then I do not use cheap shit pads.  I only use hope sintered

I think your over estimating your brake temp considerably

Stopping

Mass of bike + rider = 100kg

Speed = 10 m/s (36km/h, about 22.4mph)

kinetic energy = 0.5 m v^2 = 5000J

A basic 180mm steel brake rotor weighs about 150g and the specific heat of steel is about 0.5 J/gK (Joules per gram-degree), so converting 5kJ of kinetic energy into heat in the rotor should increase the rotor temperature by 67 degrees (C), assuming none of the energy is absorbed by the brake pad, caliper body or brake fluid (not realistic, but useful to identify an upper bound for the rotor).

Descents

To maintain constant speed on an even slope, the change in gravitational potential energy must equal the heat energy extracted by braking (plus other sources of friction and drag that we’re ignoring).

Descending a 1 in 10 slope for a 100m distance gives a height change of 9.95m (not 10m, because the distance is along the hypotenuse).

Gravity on earth is about 9.8 m/s^2.

Energy change = m g h = 100 * 9.8 * 9.95 = 9751J

This would increase the rotor temperature by 130 degrees.

Descending a 1 in 10 slope for a 100m distance gives a height change of 9.95m (not 10m, because the distance is along the hypotenuse).

10m isn’t a very big hill.

Sometimes I’m fortunate enough to go places a bit hillier than that.

In fact, come to think of it, even living in Cambridgeshire that’s possible. Madingley Mountain is higher than that!

I’ve had good results getting rid of mineral oil this way.  Doesn’t take much (10min at 200C).  Equally, getting them properly hot on the bike also does the job.  I did it a few times when trying to diagnose leaking calipers.  Once I eventually got the calipers replaced, one final blast in the oven and they’ve been perfect since.

Last ones I did , I threw in the oven when it was doing a prophetic cleaning cycle. Think it’s about 450 degrees for an hour. Uber pass were fine after, the other lads which I can’t remember the name of turned to dust

i have always used the gas hob. Depending on what has contaminated them you can sometimes see a colour in the flame. The problem with replacing pads is that you have to wait for the postman to deliver them.

I sprayed mine with isopropyl alcohol then blowtorched them.  They were ok after.

Didn’t work so well with Greene King IPA.

I think your over estimating your brake temp considerably

Did you work any of that out or just copy and paste it from here to look scientific?

https://bicycles.stackexchange.com/questions/47326/maximum-brake-temperatures

If you’re hard on brakes light brown to bluish discoloration is easily possible which I think from memory indicates around 250-300 degrees C?

The tandem brake discs are blued badly.  Regularly get well above boiling point as you can tell when you put water onto them.

Disc brakes are badly misunderstood by many mtbers.

I always tend to think its my disc brakes that don’t understand me.

I think your over estimating your brake temp considerably

Stopping

Mass of bike + rider = 100kg

Speed = 10 m/s (36km/h, about 22.4mph)

kinetic energy = 0.5 m v^2 = 5000J

A basic 180mm steel brake rotor weighs about 150g and the specific heat of steel is about 0.5 J/gK (Joules per gram-degree), so converting 5kJ of kinetic energy into heat in the rotor should increase the rotor temperature by 67 degrees (C), assuming none of the energy is absorbed by the brake pad, caliper body or brake fluid (not realistic, but useful to identify an upper bound for the rotor).

Descents

To maintain constant speed on an even slope, the change in gravitational potential energy must equal the heat energy extracted by braking (plus other sources of friction and drag that we’re ignoring).

Descending a 1 in 10 slope for a 100m distance gives a height change of 9.95m (not 10m, because the distance is along the hypotenuse).

Gravity on earth is about 9.8 m/s^2.

Energy change = m g h = 100 * 9.8 * 9.95 = 9751J

This would increase the rotor temperature by 130 degrees.

Just buy new pads, they are not expensive and quite and important part of the bike!

Re:  sweating the oil out – obviously you clean them up as much as possible with disc brake cleaner first.  The heat then pyrolyses (possibly with some combustion also) the oil that is left.  There will still be some “contaminant” left in there, but it will not be friction-reducing oil, it will be carbony stuff.  You will need a high temperature to achieve that, I am not sure a hot oven will quite make it, hence the blowtorch.

Descending a 1 in 10 slope for a 100m distance

But our brakes work much harder than that when we need to stop from 30mph at the bottom of a 1:5 in a third of that distance…

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Just buy new pads, they are not expensive and quite and important part of the bike!

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No fun when grownups post 🙁

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It’s a tricky one – my life depends on these pads and they’re contaminated. Shall I attempt a half-arsed bodge in my kitchen that probably won’t work, or spend a fiver on some new ones?

I coat my pads and discs in Isopropyl and then use a lighter to burn anything off.

I have recently burned my fingers using a lighter so I have just ordered a camping gas blow torch to use instead, must make sure I am not near any seals when doing this, their fur goes up like a christmas tree!

To be honest, if you usually fit £5 pads I would just buy some new ones.

That sounds snobby, lol, which I don’t intend it to sound like! I just mean that some people spend a lot on branded pads so I can see why they try to save them but for a fiver id fit new. 🙂

I don’t and won’t use cheap brake pads.  False economy.  Lightly contaminated pads can be cleaned up easily – why throw them away when its easy to save them.  The only ones that this failed for for me were cheapo ones – they fell off the backing plate.  If the bond is destroyed to the backing plate when heating in a flame then its likely they will do the same when used hard when riding.

Buy cheap – buy twice

Done it on bimble shop bike not on the gnarr bike.

I don’t and won’t use cheap brake pads.  False economy.  Lightly contaminated pads can be cleaned up easily – why throw them away when its easy to save them.

I’m with you… I’ve blowtorched Shimano ones no problems from  light contamination and mostly they are then more reliable than cheap ones.

@tj
The temperature of an oven is nowhere near to the temperature of a blow torch .

I’ve got some leaky calipers on the fatbike.  If I’ve not ridden it for a week or more, I need a steep hill and some hard braking to get them to stop squealing and start working well again.  No bother where I live, I don’t need to brake heading up the hill from my house, and there’s plenty of opportunity to get them up to temperature from the top.

I wanted to use it for a ride last week where there isn’t a decent downhill until mile 13.  Thought I’d try the hot air gun instead.  checked disc temp with a spitty finger, and got the pads similarly hot, got a bit of smoking and the bottom-of-a-big-hill burny smell.

Worked a treat.

Some interesting reading on the  boiling point of various fluids DOT and mineral. We know that the fluid is insulated from the heat by the piston but the radiant heat must be similar to the surface of the disc / pad.

According to the web site Magura Royal Blood boils at 120 degree C. I would think if the pads were seeing anything close to 200 degrees  that would cook the fluid, but it doesn’t seem to happen.

http://www.epicbleedsolutions.com/blog/dot-brake-fluid-vs-mineral-oil/

I’ve soaked in meths and then set fire to them.  Seemed to work.  Also rubbed them with alcohol. In the absence of Isopropyl, the wifes gin works quite well

Well over 200degrees north country boy.  Want to see some nicely blued stainless discs?

We know that the fluid is insulated from the heat by the piston but the radiant heat must be similar to the surface of the disc / pad

You would be surprised how much difference there is between pad temperature and fluid temperature. A lot of race car brake pads work upto 700 degrees C yet the best brake fluids have a wet boiling point of only 270 degrees C.

I have had my fair share of very hot brake discs

1. Don’t get shit on your brake pads.

2. Just buy some new ones if you do

I don’t think I’ve ever managed to contaminate brake pads, but I think I’d just replace them.

so what about putting then on the stove. would that be hot enough?