Anybody else keep getting their disc pads contaminated?

At least once a week I have to take the pads out, wash them clean with isoprop and sand them down (and obv clean the rotors! 👿 )

Thing is, nothing seems to be leaking on the bike. All I can think is that it’s gubbins from the road (I have a 2 mile ride back on the roads from my local trails).

Any one have any tips to sort this or should I just smash the hell out of my bike and start over?

(symptoms I’m assuming are contaminated pads are random really loud howling, super grabby over-the-bars brakes at low speed – no power at >5mph)

Are you losing brake fluid? Getting overspray from chain oiling ? Are they glazed rather than contaminated?

They look shiny in patches when I take them out, this is what I am sandpapering off.

Forgot to say as well, that the brakes are SLX only a couple of months old. Pads are currently SSC organics, had same problem with Shimano ones before hence their replacement.

Don’t think I’m losing fluid – they still feel solid anyway.

Front AND back?? That’ll be the tell tale I would think.

If its just the rear Id bet you’re getting oil come off the chain onto the disc, if so you’re not using any daft non-bike oil or anything?

If its both of them then did you break the pads in well, if you’re sanding the tops off are you breaking them back in? Might not be the problem but who knows, and they should be broken in.

Oh, and howling when being used or noise when just pedalling?

I’ve always wondered about this theory of brakes getting contaminated from road spray and dirt.

If the roads are that oily and dirty, why aren’t car brakes affected?

Are you using muc off to clean the bike? Or another type of cleaner?

Mine squealed like a pig after cleaning it after the first ride with new brakes… burnt off and worked ok after a few squealing grabby stops..

Could be you’ve contaminated your pads with oil and that has soaked right in. Now everytime you ride, some of it is transferring to your discs.
You clean your discs….ride again and it comes right back.

Have you tried cleaning your discs and perhaps a new set of pads as well on at least one end of the bike (asusming it’s affecting both ends)?

I would say it’s the caliper not being set up correctly myself rather than contamination. I’d say that’s the main reason for brakes problems full stop but certainly in your case.

Have the brake mounts been faced? Has the caliper been aligned when setting up the spacing?

Pad contamination in my opinion and experience, is a complete load of bobbins, just like bedding brakes in is.

Pad contamination in my opinion and experience, is a complete load of bobbins, just like bedding brakes in is.

I got a fair bit of PTFE oil on my rear brake on Friday night (I’d sprayed it into my swingarm to try to cure a creak) when I flipped the bike onto its back wheel to move it. I didn’t realise I’d got it on the brake until I rode on Saturday. Initially there was nothing there – I could pedal with the brake held full on – so I slapped a bit of mud on the rotor and did a few stops and got about 50% back. Rode the rest of the day on patchily damp trails and it gradually sorted itself out and is completely fine now.

I would deduce from this that you need to get a substantial amount of oil or fluid on your pads over a substantail period of time to wreck them. Or I’m just a lucky chap.

I’ve never cleaned a brake pad. Surely they have to be self cleaning ?

Could be you’ve contaminated your pads with oil and that has soaked right in.

are pads porous ? They seem quite solid to me…

samurai – I suggest you get some chain oil on your pads – then try riding. It is perfectly possible to contaminate pads – or try a leaking fork seal pumping oil all over the brake. Both have happened to me.

I won’t get into another debate about bedding in tho 😉

However you are perfectly right in that You don’t pick up contamination from the road and that a lot of brake problems stem from them not being set up and maintained properly.

Dusty, you are a bit lucky… don’t try this but put a bit of 3 in 1 or something like that on your finger and wipe it round your discs lightly. Then cycle at 15 mph towards the side of your car and when you’re 5 metres away try to stop. Ta daaa… off to the body shop to get a quote.
(you can try again and again but it will shaft the pads and braking alone won’t get rid of it once that oil gets into them).

But, it depends how contaminated they get I suppose… also, ever heard of the baking in the oven trick? Well, I did that once and had a pair of useless pads back to perfect (weren’t sintered)… on a bit of tin foil, 20 mins at 220 (served with dauphinoise potatoes and cress). Some people say it doesn’t work but it worked 100% for me and thats from a pad that was practically non-existent, absolutely unrideable.

Cos retro83 is solving the problem by sanding it then it returns it can only be contamination cos the behavior re-appears after fixing and hence I don’t think its setup on gut reaction. It could be bedding in as a very very long shot but much more likely its contamination and I’d think more likely that it could be self-inflicted too.

Now he (or she) will say he rides to work through an oil refinery or something.

Sweep, if I’d tried that I’d probably still be in A&E now! When I first hit the brakes there was virtually no retardation at all from the rear one – imagine brake pads made of ice. I was all set to go home and get the other bike, but laziness and desparation made me try the mud on the rotor trick/old wives tale/surprisingly good way to bed your pads in.

Retro83, I’m with Sweep in that it surely isn’t happening at both ends, if it is only the rear then contamination from the chain or gears is the only possibility I can think of.

Cheers for the replies so far. Much appreciated.

The brakes are getting contaminated(/whatever) at both ends, but not always at the same time – some days its just the front, or just the back, other times both. Sometimes I go for a couple of weeks with no problems then it happens every day.

Setup is fine AFAIK but I’m not an expert on brakes! At least the pads are centred, pistons not overly sticky and I do clean them after muddy wet rides with isoprop (I remove the pads when doing this). Haven’t noticeced and leaks at all from the pistons.

I would say it’s the caliper not being set up correctly myself rather than contamination. I’d say that’s the main reason for brakes problems full stop but certainly in your case.

Have the brake mounts been faced? Has the caliper been aligned when setting up the spacing?

Pad contamination in my opinion and experience, is a complete load of bobbins, just like bedding brakes in is.

Mounts not faced admittedly, but I don’t understand how this would make the brakes go from powerful + really good to really howly and awful performance.

I only use isopropyl alcohol to clean them, no muc-off disc cleaner or anything.

Also, it’s not bobbins 😈 try putting a dab of chain lube onto your pads.

Now he (or she) will say he rides to work through an oil refinery or something.

He – and no oil refinery, but I do notice the lovely rainbow coloured oil patterns on the road whenever it’s damp out. Don’t think it’d take a wild leap of imagination to see how it could end up on the rotors. 😀

Pad contamination in my opinion and experience, is a complete load of bobbins

No, it’s not. Why when I replace not-working-very-well pads with new ones are my brakes suddenly back to perfect?

Barnes – sintered pads are porous, they are made from particles compressed together hence porous.

To the OP – I do get this. Previous pads were rubbish at the start of a ride, so I put in a few hard braking efforts and they’d gradually come back to a reasonable level.. then by the next ride they were naff again.

On a previous bike I used to find a muddy gritty puddle, grab some grit in my fingers and rub it all over the disc. You can feel when the disc’s clean, it starts to squeak under your fingers. This works quite well ime.

The other day I did a brake test down my hill, pedalling hard downhill and hauling on the brakes – they were really nice until suddenly they stopped working well near the bottom. Like brake fluid had leaked out past the caliper seals and onto the pad. I gave them a good clean, rinse with water, sand down and I baked them in a flame too – still wasn’t that great. I put the pads from the rear on the front and it they were superb again. I’ll try the oven thing next time it happens.

Cheers molgrips, that sounds exactly like what happens to mine.

retro83, you ever not bothered to clean the bike down, or touch the brakes in any way? Are they better if left alone?

you can get stuff on your pads and they’ll not work as well right there and then, I’m not disputing that. That this will make them never work well again until you do something to the pads is a big complete load of bobbins. I’ve had oil on my pads loads of times, easy to do when you’re spraying oil about on the chain. I’ve even done it on purpose to prove the point.

It’s a braking surface, any contamination wears off real quick through normal braking. If an issue stays longer than a couple of hard brakes then it’s something else.

molgrips, your issue sounds like contamination in the hydraulic fluid or a dodgy valve in the brake itself.

I used to take pads out after every ride & clean down etc.
Then we had kids.
The pads have never been out of my Juicy 5’s, & they wont until they wear out.
Just leave them alone, live with the odd squeal etc & pull harder if they are fading.

Sometime things just need to be left alone. I’ve long since passed the ritualistic washing & lubing. Just hose off the loose stuff & give it a blast of Teflon spray.

retro83, you ever not bothered to clean the bike down, or touch the brakes in any way? Are they better if left alone?

Yeah that’s what I did originally. My fairly rigourous brake cleaning regime came about as a result of this problem. Also my understanding was that isoprop would be 100% safe to clean brake bits with. Is that not right?

Only bits that get cleaned are mud tide marks on suspension (using dry kitchen roll) and chain (removed from bike monthly or so and wiped down then lubed with finish line dry)

Barnes – sintered pads are porous, they are made from particles compressed together hence porous

containing voids does not mean porous – it depends how big the voids are. If brake pads were porous, they would fill with water which would then boil and probably cause them to disintegrate or delaminate under heavy braking

I am unfamiliar with the isoprop stuff, was just trying to assertain if maybe part of your preperation was actually making things worse for you, I know mine were sqealing this weekend and they were brand new and perfect last weekend, this did cure itself and I put it down to using Muc off to clean the bike.

You could try another cleaner, sounds like a right pain in the ar5e on good brakes that are not very old, as sugested it might just be worth re setting them again to be sure, and change your cleaning routine make sure its not anything your doing.

So, it sounds like its oil ‘off the road’ or oil ‘out of the calipers’ really doesn’t it?
I reckon you’ll suss it out.

Ever had calipers apart or anything like that? O-rings on banjos those kind of things? Just check the daft stuff, have a look where oil could possibly come out and reach the pads or rotor. Right oil in there too? Dunno if wrong stuff could attack seals or something? Someone on here will know.

Few people say contamination fade always clears with just hard braking, well, I tried exactly that when it happened to me, but after half an hour of repeated trying, probably 100 hard as I could pull stops the brake was still probably at no better than 15% power. Certainly couldn’t have ridden on a trail on anything but complete flat or uphill. So it definitely can shaft things up. But, the last ditch oven trick worked 100% in no time at all. This was on standard OEM pads on 07 XT brakes and chain oil that had sprayed up a bit onto the rotor (dunno what it oil was, it was french in a clear bottle, my dad had bought it and was chucking it out, it looked like 3 in 1 viscosity on inspection afterwards).

WARNING:

Not all makes of pad can take heat from baking or holding over a flame. I’ve ressurected some contaminated Avid pads twice, by holding them over the cooker with a pair of pliers. Good as new.

Tried that with some Hopes. The pad material separated from the backing plate. Oh dear. Araldited them back on, as I din’t have any spare. Went out for a ride. They worked, until the pad material separated from the backing plate, again. Several miles from home, of course.

Heat from discs while riding is nowhere near the heat from a flame. An oven wouldn’t be as hot, so might work. What you’re doing is burning out the contaminating oil from the pad material; this may take more heat than the pad glue is designed to withstand.

But it’s a risk. Best to ask manufacturers/distributors what to do, really (they will probbly tell you to buy new pads).

Hopes, particularly, improve loads, if you get mud on ’em (Did Hope mechanics once get done by customs somewhere in Yerp, ‘cos they had a bottle of mud with them?).

SFB, what has solidity got to do with porosity? A breeze block is quite solid, but quite porous too, as is sand.
Fill a bucket with sand, punch it as hard as you can…..it is quite solid. Now pour a pint of water on top of it…..does the water disappear into the sand…..it is porous, but solid.

Brake pads are also porous.

My comment about possible brake pad contamination was just a thought – no more, no less. I have never had the problem that the OP describes but it is one more thing that should be considered.
I am not sure about the set-up thing, as surely set-up does not vary? They are set-up in a certain way, but the performance varies.

Dustylilac……a spraying of oil onto a disc brake rotor/pad shouldn’t cause the same level of contamination as some kind of prolonged exposure.
I agree that in normal circumstances, pad contamination isn’t an issue. Any surface contaminants will be removed when the brakes are used ‘in anger’. But, what if one of the calipers is leaking slightly and while the bike is being stored, the pads are actually soaking up fluid? Again, just something to consider.

Takisawa & retro83….what is the point of removing/cleaning brake components religiously. They don’t need it.
Retro83, IPA comes in various forms. Where I used to work we used it as a flushing solution and we had to get the highest grade possible to ensure that nothing was left behind. Perhaps low grade IPA leaves some kind of film on the rotor?

SFB…taken from wikipedia:

Porosity is a measure of the void spaces in a material, and is measured as a fraction, between 0–1, or as a percentage between 0–100%. The term is used in multiple fields including ceramics, metallurgy, materials, manufacturing, earth sciences and construction.

and some other definitions here:

http://www.google.co.uk/search?hl=en&defl=en&q=define:porous&ei=ZAy1SfPZBeDDjAeBn7DOBQ&sa=X&oi=glossary_definition&ct=title

so yes, porous DOES mean containing voids.

We can all be pedantic…….

Take your brake pads and use some very accurate scales to weigh them. Put them in some water and leave them for an hour. Dry the external surfaces and then weigh them again…..do they weigh the same?

Just had a thought. DO you have some crazy assed disks with your name engraved on them or something? it might explain the patchy wear on the pads and the noise and grabbing. It’d certainly explain why front and back have a problem.

Another possibility is that your wife has put a huge life insurance policy on you and is squirting oil on your disks at night. That’d be the first thing I’d check.

Oh.. if this happens in dry weather too then there’s no way its getting contaminated off the roads anyway, there’s nothing to spray up when its dry anyway.

If so, then its gotta be oil out of the calipers pretty much. Cos even if you were getting contamination from ‘chain and rubbish lube’ it would never affect the front anyway.

Check calipers and check you haven’t got dot 5 in a dot 4 only system thats cocked things up over time (think thats the combination that leads to trouble that can eat away at things? someone?)

so yes, porous DOES mean containing voids.

interesting, you live and learn, I thought it referred specifically to permeability, which depends on the pore structure. Voids can be closed.

Dry the external surfaces and then weigh them again…..do they weigh the same?

has anyone done this ? What was the answer ? Is the structure so open the steam can escape harmlessly ?

SFB…….dunno if anyone has done such a porosity check…I could have a go if I was still employed at my old place, but without very sensitive scales I would think you’d struggle.

I suspect the rate that a pad absorbs water would be slow enough that in normal riding conditions, it wouldn’t be an issue and that any heat in the pads would quickly cause the water to evaporate out again. Anyway, water isn’t a great lubricant anyway and I wouldnt’ have thought it would affect disc brakes overly so.

I suspect the rate that a pad absorbs water would be slow enough that in normal riding conditions

but that’s my point, if it lets any water in, that will convert to steam on heavy braking, and unless it can escape quickly it will blow the pad apart

Pads do soak up fluids. If a pad is made from compressed particles, the voids would not be closed. When you brake the vapour from any contained water comes out of the sides of the pad material if it boils.

molgrips, your issue sounds like contamination in the hydraulic fluid or a dodgy valve in the brake itself.

No, because it goes away when I get new pads. Then other problems can occur like for instance the thing that happened the other day with the sudden loss of power during a single braking run. I heated and cleaned and soaked, which helped a bit. Then I swapped front and rear, and the front was brilliant again and the rear rubbish. Has to be pad contamination. Possibly from leaking brake fluid in that case.

sfb, why would it necessarily ‘blow the pad apart’? Where does this destructive force come from? You are talking about a couple of grams of water potentially turning to steam. I am sure the pads can tolerate that.
The pad isn’t going to go superheated and any steam will make its way out easy enough.
Depending on the riding, the residual heat in the pads in between heavy braking will probably be enough to evaporate off the water. Water doesn’t have to be boiling to evaporate.

Anyway…..this is getting a bit OT.

Takisawa & retro83….what is the point of removing/cleaning brake components religiously. They don’t need it.
Retro83, IPA comes in various forms. Where I used to work we used it as a flushing solution and we had to get the highest grade possible to ensure that nothing was left behind. Perhaps low grade IPA leaves some kind of film on the rotor?

Only started cleaning them like this since I started having problems, I agree about the grades of IPA thing though, I think my is >99% pure from memory as it is for cleaning computer chips, but I will double check that. Perhaps the last 0.5% is pure teflon. 🙂

Check calipers and check you haven’t got dot 5 in a dot 4 only system thats cocked things up over time (think thats the combination that leads to trouble that can eat away at things? someone?)

These run mineral oil, plus I can’t ever see any oil around the pistons and for it to get onto the pads/rotor there would have to be a reasonable amount leaking I would have thought. Seeing as the road oil thing seems to be a non-starter, I’ll have to have another good look at them (damned hydraulics – bring back Vs!).

Just had a thought. DO you have some crazy assed disks with your name engraved on them or something? it might explain the patchy wear on the pads and the noise and grabbing. It’d certainly explain why front and back have a problem.

Nope, sadly I’m just not that cool. I have an Avid 185 (with correct adapter) on the front, Shimano on the rear. Had the same problem with a shimano 160 on the front too.

Another possibility is that your wife has put a huge life insurance policy on you and is squirting oil on your disks at night. That’d be the first thing I’d check.

Wouldn’t be too surprised about that actually 😕

Just got home and checked the pads and they weren’t shiny this time, they look damp, but I can only assume this is oil.

The pad isn’t going to go superheated and any steam will make its way out easy enough.

well, if they are permeable then one must suppose this is the case…

that looks like a permanent leak, I’m surprised no-one has suggested oil might be leaking out of the brakes onto them.

They have suggested its a leak!

FWIW, I have exactly the same problem. I have had it on two different bikes with 3 different sets of disk brakes. I have also inspected my current callipers very carefully looking for leaks so I am 99% sure it isn’t leaking callipers in my case. My current theory is that it is oil from my chain getting on to the disk somehow or contamination from lovely London roads. It is damn annoying. Fit new pads and clean disks – lovely braking. A few days later, mysteriously crap rear brake that provides no retardation at all. It drives me mad.

Just in case chain oil is a common denominator between us “suffers”, I use Purple Extreme chain lube. I might change to something more clingy just to see if it helps.