First up, I'm not after a diagnosis, I'm pretty sure I know what's wrong. Just telling a story, having a moan….

So I deicde my 2006 Louise FRs need a service as they have sticky pistons and won't centre over the disc and drag a lot. Fine. So I clean out and lube the pistons carefully, lots of faffing, and get both pistons on both brakes moving evenly and smoothly, and bang on centred over the disc. Lovely. Once reassembeld the test on the road outside shows a lack of power and lots of screeching. Balls. I assume somehow that the pads have got contaminated even though I took them out during the service. Idiot. So I take them apart and clean up the discs, pads and calipers again, reassemble and test. On the road again the power starts to come back, it looks like I've fixed them. Wonderful. Put the bike away. Next ride a few days later and we're back to no power and screeching again but as the ride goes on, they get better so I think little of it, wash the bike and put it away. Lovely. Next ride, back to square one. Screeching and pant filling lack of power. Arse. So, on a longish road downhill back to home I do lots of hard braking and really cook the brakes. By the bottom of said hill I've got shedloads of power and silent brakes. Excellent. This time I don't wash the bike as it's not dirty and fully expect the brakes to be fine last night, (2 days later) just as I'd left them. Back to square one again. AAARRRRGGGGGHHHHHHHH!!!!!!!!!!! So anyway I contine on my ride. After a while it starts to rain. At the tiniest sign of water on the discs I can feel the power coming back again. 5 minutes later and the brakes are at their very best again. How the hell does that work, then? If I wash the bike, I loose power. If I don't wash the bike, I loose power. If it rains I get accidental endos and huge skids. I give up. Still, it adds some fun to a ride, will I stop or not? Roll up! Roll up! Place your bets folks!

(For the record, I've had these brakes 3 years and they've been faultless and silly powerful and I've never touched them. I reckon the problems are a cross between contamination and aftermarket pads. With Magura pads I can virtually squirt GT85 straight on the disc and it has no effect. If these pads don't buck up their ideas soon, they'll be in the bin, but they have been in there for a while already, strangely…..)

Are your brake pads made from unobtainium a la Oakley nosepieces and ear socks – eg more grippy when wet? 🙂

your wife has been buttering your discs*

*no, that's not something rude

Brakes…Aggghhhh!

Assuming that everything is aligned and lubed correctly,

I reckon you should give the pads a good rub-down with emery cloth to remove glaze and then spray the disc with brake cleaner and clean thoroughly.

It could also be worth spraying and burning the brake cleaner off the pads to help shift any grease/oil that's on there, if you're careful.
This worked for a set of mine that got contaminated when the brake hose started leaking all over my caliper.

Copper grease on the back of the pads allegedly helps to reduce noise.

Hot buttered discs?
Sounds nice. NomNomNom.
🙂

Assuming that everything is aligned and lubed correctly,

I reckon you should give the pads a good rub-down with emery cloth to remove glaze and then spray the disc with brake cleaner and clean thoroughly.

It could also be worth spraying and burning the brake cleaner off the pads to help shift any grease/oil that's on there, if you're careful.
This worked for a set of mine that got contaminated when the brake hose started leaking all over my caliper.

Copper grease on the back of the pads allegedly helps to reduce noise.

You haven't read the OP, have you?

😉

Some other guy on here had a similar re-occuring brake failure and it was fluid seeping past a seal and onto the disc while the bike was standing. He would then run the bike, burn off the contamination and have good brakes until he got the bike out of his shed for his next ride.

Good luck!

Yep, I've had that problem imp999. Turned out to be a tiny, basically invisible, leak that was fixed after I replaced the caliper/hose attachment.

Good piece of venting. I sympathise. 🙂

I fully appreciate that there are huge advantages to hydraulic disc brakes over cable rim brakes. At present, my Juicys are working rather well, and I am riding hard enough that I'm definitely feeling the benefit of the power and control that they provide.

BUT.

It is this sort of bizarre voodoo nonsense that really makes me hanker for simpler times. Peter is clearly a competent and well equipped mechanic. He has done more to maintain his brakes than many of us do. And they have a persistent, dangerous fault. He has a speculative diagnosis of it, but realistically, fixing it will be trial and error at best.

I know that cantis didn't produce anything like as much power. I know they were a pain in the wet, and that in some consistencies of muck they wore away rims and pads pretty fast. But they never, never developed faults that you couldn't diagnose or repair. Essentially, if you kept the cables clean and everything bolted up nicely andpaid a bit of attention to thingas like pad toe-in and straddle wires they just worked. Albeit not very well. And if they weren't working you could see why and fix it. And the best solution to a fault was never to sacrifice a black cockerel over the bike and hope for the best.

10 years down the line we will have electronic shifting. That's going to be horrendous. 😀

Your dog pisses on the wheels in the garage?

tinsy….I was going to say that there is a cat getting in & spraying on them…..

PP is sleepwalking, and spraying them himself? Maybe not with wee??

I've some BB7s that have screeched from new 🙁

BigDummy – Member
…10 years down the line we will have electronic shifting. That's going to be horrendous.

Hopefully there will still be a few single speeds left with cable brakes.:)

Funnily enough I have just gone back to cantis on one bike. The new breed of cantis are much less hassle.

Anyhow I thought the purpose of brake squeal was twofold – to warn those in front of you, and to let you know you are slacking.

Dear Peter

First I would like to apologies if I do sound patronizing, but it is not my intention.
Have you try contacting the manufacturer/importer of the brake to let him know about the problem?
It might be a known issue, or something very simple to fix. Most of the time, technical services of a specific brand are able to offer very good advice on how to fix such kind of trouble.

Hope you will be able to fix your brake soon.

Sorry not to be able to help more.

All the best

El capitan

Captain, the brakes are fine. There are no neaks before or after I serviced them. When I serviced them I lubed the pistons with some brake fluid as it was impossible to get copperslip round the whole piston due to the design of the caliper. I have done this before! I'm assuming that some of this fluid found it's way onto the pads after I refitted them and because they are a different make of pad to what I usually use (not Magura pads) that they are not as tolerant of contamination as the Magura pads seem to be. If this continues I'll just fit some Magura pads which I can virtually guarantee will cure it!
Thanks for the comments though!
😀

apologies if I do sound patronizing

Do you mean 'apologise' and 'patronising'? I'm just not sure you're clever enough for this thread 😉

Sounds to me like imp999 is most likely, failing that, just change the pads, as you've said.

Crikey, was that it PP, I thought maybe the ghost of Jackson was maybe taking a leak on em as he moonwalked past, or at least something random, lets hope it is something more sinister and you can report back that your new pads squeal like a bandshee on crack after being in the shed.

Fliipin annoying brake squeal after a bit though isnt it, had to buy a new caliper for a Shimano brake that wouldnt shut up no matter what I did, sometimes it seems things can wear a bit and cause it from nowhere.

Fliipin annoying brake squeal after a bit though isnt it

Ahh, see now, this isn't 'squeal' as such. Not how you imagine it, anyway. Maguras make a gentle 'warbling' sound usually, caused by the Galfer wavy disc, but this is a very loud groaning moan caused by the pads failing to grip the disc and juddering. Imagine pressing your finger on wet glass and moving it to make a noise, similar to that!

This was just menat to be a fun thread/small rant. I know what's happening!
😀

Hence not one serious reply from me, however a little bit of me hopes your wrong and you have some kind of spectral phenomenon occurring. 😈

superstar pads? 😉

Sounds similar to what i had on a set of Avids, really load groaning and vibrations. after much meddling with alignment, caliper bolts etc i changed pads and didnt mess with anything else and the brakes were just fine….

superstar pads?

Actually, now you come to mention it…………….no.

I've had these pads before and they've been OK. Not as good as Magura pads, but OK for the money.
🙂

Same disc all those three years? I wonder if it's worn with the pistons, and now as you've re set the pistons the whole thing's all misaligned?

throwing ideas around….

Nahh, it's all fine. Discs fine. Caliper fine. All aligned fine. All bled up fine.
Diagnosis is operator is not fine and got brake fluid on the pads. Go and por some fluid on your hands then rub them together, GO ON!! They feel sorta juddery. That's what it is. Judderyness twixt pad and disc. Caused by brake fluid on the pads.
😀