A friend has dropped of their son's bike to help out as the brakes don't work
A few questions later and it seems dad has applied some WD 40 as they were squealing!
I've tried brake disc cleaner, taking the pads out and the discs off and cleaning with boiling water and fairy - then giving the faces of the pads a sanding down.
This approach seemed to have worked, but a short test ride showed that the benefit was short-lived and they are still showing poor braking effort.
Is there anyone who has managed to sort this problem or should I advise pads and discs?
(Clarks CMD-17 on a wiggins kids bike if that makes a difference)
Thanks
Alastair
PS this is really a friends bike, not a thinly veiled attempt to hide a personal lapse of judgement!!
burn the pads and disc. Burn the contamination off. You might need new pads if they are really soaked but I have successfully rehabilitated pads in the past
Thanks TJ - do you mean burn as in - put in the oven, or burn as in - put in a flame?
ie is it temperature or flame that works best?
Either mate. Stick them on a camping stove until they stop smoking. My SO says no bike bits in the oven! So that’s what I do.
I've had success by holding pads (with pliers!) over a gas burner before so all the crap is cooked out - there's a risk that the material unbonds from the backing but if it doesn't work you'll be replacing them anyway. Hot ovens are also meant to work but the gas is quicker.
Thanks - will try and then report back!
I second the burning technique. I've also saved a pair of pads from an early end by heating.
I used a blow torch. Just heat to cherry red then leave to cool. They smoke a bit as the heat rises but once cool seemed ok and worked fine until they wore out.
Give them a good bedding in after you've done this (a few good braking sessions down hill, cycling the brakes from cold to very hot each time). Works for me.
Just clean the discs with isopropyl alcohol
Then tell the dad he needs to buy new pads
1. Why mess around trying to burn the contaminates off when they are not your brakes
2. They are for kids bike (i wouldn't want to take the risk that they could fail later on)
3. Having to pay for new pads will hopefully stop the dad next time from trying to fix something he doesn't understand
You can soak in alcohol or soapy water for a decent amount of time - or bike cleaner e.g. Muc Off. The pad material is porous so you need to let it diffuse out. Burning it off may leave a greasy residue depending on what's on there, but I'd have thought that WD40 would be volatile enough to burn off or diffuse out. A dishwasher cycle will probably also help. Or you could soak in dishwasher detergent - it's very alkaline.
I've tried loads of things and probably ended up with surgically sterile pads and discs in an effort to resuscitate brakes, without realising that you can end up cleaning the rotor too much which means that you'll have to bed them in again.
I've never had any luck with decontaminating pads, they never get back to full bite in my experience. I just replace them now, I also am really cautious about using spray stuff anywhere near the brakes and cover the caliper and rotor with a rag when using things that might contaminate.
Nice big hill.
TBF escrs has it. What happens if all the burning/ soaking/ alcohol etc doesn't work and little Jimmy smashes himself into a baby robin on a conveyor belt? How much is a pair of pads vs dental work?
Never understood the logic of fannying around burning pads and scrubbing and soaking them to within an inch of their life to rejuvenate them.
Life's too short. Tell him to spend a tenner on a new set of pads.
Put them in the oven and bake at 200 degrees for forty minutes. The oily contamination will mostly sweat out, once baked drop into warm soapy water to clean off and replace.
Brake rotor cleaner (IPA + fancy marketing I suspect) from the local motor parts store on the rotors worked for me, and then pads in the oven at about 200C (leaking shimano calipers).
I think pads should be able to withstand that temperature, as they will surely see that in normal use (perhaps rarely). I think a naked flame might be a bit brave. Or new pads, they're not very expensive.
IPA/brake cleaner the rotors, then new pads imo.
Oven works a treat for me so far
disc brakes can and need to get very hot in use. The tandem rotors are blued from heat
Soaking in enough meths for a few minutes to cover the top of the pads, then burn it all off by igniting with a match, lighter or whatever.
An oven might work for very slight contamination but without a naked flame to initiate actual combustion, all you're doing is thermally degrading the oil into other decomposition products.
Sure the lighter fractions might volatilise, but you'll still be left with something to cause you a problem.
Replace, never had any luck trying to revive pads.
Also unsure I'd want to soak someone else's kid's brake pads in solvents and dish soap (which has a high salt content btw). Certainly experienced pads failing due to the material separating from the backing and just wouldn't mess around with it personally.
It wont work. Alcohol scrub rotors, fit new pads
Another vote for holding them over a flame with a pair of pliers. When they stop catching fire theres no oil left
Ive always had this work but some people have pads seperate etc.
Nothing to lose by trying.. if it works you save yourself a pair of pads.. if it doesn't you still have a pair of wrecked pads...
Burning them with a gas flame can get them serviceable again, but new pads is obviously best. I've done it on my commuter bike, but put them on the back just in case they do fall apart and lock the wheel up unexpectedly.
disc brakes can and need to get very hot in use. The tandem rotors are blued from heat
Heat and compression.
I'd do it on my own brakes but not someone else's kids.
Life’s too short. Tell him to spend a tenner on a new set of pads.
Is the correct answer
Just done similar, front pads were soaked in oil after neglecting to change a leaky fork seal for about 5 years. Unknown model of Clarks hydro disc on a cheap pump track bike so decided to try some of these methods rather than going through the grief of identifying and ordering new pads and rotor. Soaked the pads in brake cleaner then held them over a naked flame for 2-3 mins each, and did the same with the disc but just ignited that and let the cleaner burn off for 30 secs. A quick sand and bed in procedure and the whole lot feels as good as new.
I’d do it on my own brakes but not someone else’s kids.
is probably the key point
When you can buy 4 sets of pads from Disco for £25 why fanny around with burning them? Just buy new ones have have a beer in the time you've saved.
Burn pads with a gas torch until no smoke can be seen. Then give pads and rotor a clean with isopropanol.
This is fun....we should have votes on it 😀
disc brakes can and need to get very hot in use. The tandem rotors are blued from heat
About 300C to make steel blue. Gas flame is much hotter than that.
We don't need a vote, we need an objective test.
Different pad compounds, different contaminants, and different resurrection methods.
Efficacy determined by one of those brake testing rigs.
It would be great YouTube.
Here's an update on the brakes!
Thanks for all the ideas and thoughts on the topic
1st stage - soaked in boiling hot water and fairy - scrubbed for a while then dried and lightly sanded.
Passed the spin the wheel and grab the brake to see if they work test, but failed on the can they stop a grown man down his steep drive test.
2nd stage - fired up the biolite stove (how very STW!) and got the brake pads really hot, then the whole perimeter of each disc.
Much better and longer-lived braking power and better feel as I lubed the wires.
Explained to parents that if they go rubbish again new pads will be needed and advised that child uses at their risk!
Hope that helps someone in the same situation!
Cheers
Alastair