Squealing Magura Brakes

[p3eps]

I’ve been running a set of Magura MT7’s for about 2 and a half years. Apart from the initial PITA of bleeding them, they’ve been amazing.

I put new sintered pads in a few months back (replacing existing sintered pads) and all has been great.
I haven’t been riding much lately after breaking a couple of ribs, but I have been going round the block with my 3 year old who just got a bike for his birthday! During these 15mins rides, I noticed my front brakes were pretty squeaky when pulling them on.

I took my front wheel off, gave the pads a gentle rub with emery paper, and cleaned everything with brake cleaner. I also cleaned the disk.
Since re-fitting the wheel, the disk now rubs when the wheel spins. I tried pushing the pads apart with a wedge, tried loosening the calliper from the fork and tightening it again whilst holding the brake on, and tried putting the wheel on with the brake on too. I always get this slight rubbing.

Today was my first ‘real’ ride for a while, and after a few miles I ended up going down quite a wet run. My brake immediately started shrieking non stop - unless it was pulled on a little bit.
Normally, the sintered pads shriek when wet for a few stops and then they go back to normal. Not today with my ‘rubbing’… there was this high pitched shriek coming from my front brake for the rest of my ride unless I cycled with the brake partially on.

I had in noise cancelling earphones, but the noise was absolutely ludicrous! Listening to that for over an hour really spoiled my enjoyment.

Any tips on how to resolve? Not sure what has happened. Could my disk be warped?

 

[Jackware]

Have you overtightened the axle?
I seem to remember having this issue and the solution.

 

[p3eps]

Have you overtightened the axle?
I seem to remember having this issue and the solution.

Will have a look at that tomorrow - an easy one to test.

 

[Tim1023]

I had lots of problems with my brakes. They kept on becoming contaminated despite very regular cleaning. And therefore screamed like banshees. After some good advice on this forum, it turned out that the caliper itself was leaking oil onto the brakes. The LBS replaced the calipers and now all is good with the world.

Take your brake pads out and see if they have oil on the back.

See discussion here: Why do my disc brakes keep becoming contaminated? - EMTB Forums

 

[Eliadn]

Sticky pistons perhaps? On my brakes the rotor does rub every time I reinstall the wheel, but is remedied by centering the caliper. As for the noise, my brakes squeal like stuck pig in wet, but that's because of organic pads (which I will replace soon).

 

[Akiwi]

I would also think it is a stuck Piston.
Try Cleaning them with some brake fluid and make sure all 4 are free.

 

[VWsurfbum]

I had this on my MT7's recently, turned out to be a sticky piston, then i contaminated the pads so new pads again and all is good.

 

[militantmandy]

Sometimes the only way to align he caliper properly is by eye. The loosen bolts, hold brake on and tighten thing almost never works for me with Magura brakes.

 

[VWsurfbum]

the little yellow blocks have a fork prong that is there to align the caliper to the disc, as like above they dont align easily doing it the hold lever tighten method.

 

[militantmandy]

the little yellow blocks have a fork prong that is there to align the caliper to the disc

I did not know this! I am off to try this immediately.

 

[p3eps]

Thanks to all for the comments…
I’ve spent the last 2 and a bit hours faffing about with the brakes!!

I made sure the axle was the correct torque. It maybe made the rubbing slightly less, but it was still there. Incidentally… my wheel still spins pretty freely then I push it - there’s just a couple of points that scrape as it goes round.

I then removed the wheel to check all pistons were working. With the bike upside down, somehow I managed to lose all pressure in the brake? The lever was limp to pull… so I went through the bleeding process on Magura’s website (been a long time since I’ve done that - so needed a refresher!) and fired some Royal Blood through with the 2 syringes.
I cleaned everything, refitted the brake and put the pads back in and wheel on. Still the rubbing when spinning… although plenty of pressure available now.

I tried using the yellow blocks to align the caliper (also never knew they could do that!)… but still had the same result.

Now with the bike right up in the air on my stand, I sat on the floor with a head torch and hand torch trying to see the gap. Minor adjustments at top / bottom screw could get it to rub at different points - but never perfect. I then tried only the right hand pads and got them perfect… before inserting the left pads - which then scraped.

The margin for error in there must be something like 0.01mm, so I decided to cheat. The pads have loads of meat on them… so I took a bit of coarse sandpaper and rubbed the 2 right pads for a few seconds each. I placed them in and set the caliper so the gap was just visible and no more. No rubbing noise. I then did the same to the left pads (a few seconds with sandpaper) and fitted them. Still a tiny scraping noise, so another wee rub with the sandpaper.

All pads now in, and no scraping at all… albeit with slightly less meat on them than a couple of hours ago!

I can only conclude from all this that either my wheel or brake disk are not 100% true… as it seemed impossible to get the disk to not touch a pad at some point during the rotation - no matter how it was adjusted.

No doubt my wee lad will be asking if we can go for a ‘bike cycle’ when I get home from work tomorrow, so I’ll have a chance to test it out properly.

I guess I could always take the disk off and into my Metrology department at work and have them test whether the disk is true or not. I imagine given how fine the margin for error is inside that caliper that it wouldn’t need to be out by much to cause the issue I’m experiencing.

 

[RustyIron]

No doubt my wee lad will be asking if we can go for a ‘bike cycle’ when I get home from work tomorrow, so I’ll have a chance to test it out properly.

Sounds like you had a productive day. Only by working on stuff to we become good at it.

Here's a hint for aligning calipers.
Sight through the caliper so you can see light between the pads and the rotor. I work in the garage, so either I have to hold a flashlight on the back side, or open the garage door so the bright sunlight can be seen through the gap.

Rotate the wheel and watch as wobbliness of the rotor changes the gap. Your goal is to loosen the caliper a little, get the gaps equal in all dimensions, and then tighten the caliper without disturbing the gaps. You'll need to tighten each screw a little at a time. It takes a delicate touch to get it perfect.

Have fun on your ride tomorrow.

 

[Akiwi]

I also didn't know that about the yellow spacers that they can be used to align!
Also, straightening a warped disk is not too difficult, just takes patience. I have the Park tool disk alignment thingy and it definitely helps.

 

[Eliadn]

Didn't know about the yellow block can be used for alignment! I too have issues with brakes now, spend half a day yesterday trying to bleed to rear brake but the lever is still spongy AF.

 

[p3eps]

Sounds like you had a productive day. Only by working on stuff to we become good at it.

Here's a hint for aligning calipers.
Sight through the caliper so you can see light between the pads and the rotor. I work in the garage, so either I have to hold a flashlight on the back side, or open the garage door so the bright sunlight can be seen through the gap.

Rotate the wheel and watch as wobbliness of the rotor changes the gap. Your goal is to loosen the caliper a little, get the gaps equal in all dimensions, and then tighten the caliper without disturbing the gaps. You'll need to tighten each screw a little at a time. It takes a delicate touch to get it perfect.

Have fun on your ride tomorrow.

I did pretty much exactly what you describe above! I had a torch behind the caliper trying to see the gap. When I could get a gap at one pad, another would rub… and when I fixed that one, a different one would rub again!! I felt like I was going round and round in circles.

My 15 mins round the block tonight revealed that although there was no pads rubbing, the brake pressure is much lower than I’m used to. It did still work, but I’m going to need to go back to bleeding the brake again to get it back to how I like it. Got a long weekend away this weekend, so need to pack clothes and sort stuff out tonight. Probably won’t have enough time to get my hands covered in Royal Blood again until Tuesday!!

 

[VWsurfbum]

Need to true that disc first otherwise you're wasting your time as every time it rotates it will push the pistons back in the caliper.

 

[VWsurfbum]

the little yellow blocks have a fork prong that is there to align the caliper to the disc, as like above they dont align easily doing it the hold lever tighten method.

the prongs to the left go either side of the disc so the waist is the middle of the piston for bleeding and positioning of the caliper, the groove holds the cable when cutting and fitting, the two prongy bit goes through between the pads when fitted to clip on the retaining bolt when traveling with no wheels attached to stop the pistons moving etc.

 

[squeegee]

Pistons do need cleaning occasionally for best results, pump out each piston individually and scrub with alcohol with toothbrush. Use a brake block to hold in 2 pistons in and a non-marring tool to hold in the third working one piston out at a time. Clean out as much residue as possible.

After that seat pistons completely in, put pads in and get the pistons to pump out as evenly as possible, all 4 showing piston body roughly the same amount. I find this allows an easier caliper alignment afterwards and the brakes go a long time without needing adjustments, also helps pads wear more evenly. Caliper alignment tips above work for me, I use same method.

 

[p3eps]

Another update for anyone that’s interested…

Last week I re-bled the brake again until it was nice and firm. In doing this, the pads were back to rubbing on the rotor.
Again, taking great care with a light behind the caliper I spent ages lining it up the best I could. It seemed impossible to get 100% clearance on a full rotation, but I managed to get it with just a tiny little scuff noise at one point.

A few more evenings going round the block with my 3 year old - and the gentle scuff noise wasn’t loud enough to hear when cycling, so I assumed it’d be fine.

Yesterday, I was off to the trails. Much the same as the previous visit - fine for the first 40 mins of fire track and technical climb… until I got to the muddier / damper downhill part. Then, the squealing arrived… and wouldn’t go away! Now with better noise cancelling on AirPods Pro 2… but still not good enough to drown that high pitched wail out - I had to listen to it pretty much continuously for a good hour!!

Last night I took off my wheel, and removed the front rotor. Placing it on a 60cm kitchen floor tile revealed that it wasn’t perfectly flat. I took it to work today to my metrology department, who verified in a more scientific way that the rotor is slightly warped. Not a lot in it, however enough to mean that it’s never going to get through the tiny gap in the Magura caliper without touching at some point.

New rotor ordered - and it’ll hopefully be here for the weekend. On one hand I’m annoyed that I’m having to spend more money on my bike… and on the other hand I’m glad that I finally know what’s wrong and why I’ve been having such difficulty getting noise free brakes!

 

[VWsurfbum]

I'd also put new pads in at the same time as it sounds like they're contaminated?
When you bed in the disc and the pads (new or otherwise) do a few (5 ) full speed to stop, in a quick succession (getting the disc hot, don't touch) that should be done before riding and Magura suggests doing it at least once before every ride!

 

[Akiwi]

I normally go for 15 to 20 Bed in stops.
Have you tried straightening your disk?
I have successfully straightened disks with the Parktool DT-2C

 

[squeegee]

proper bed-in is critical on magura, I've had more than one pair of new pads that were essentially ruined by ignoring instructions, you can end up with squealing rotors by bypassing the break-in procedure, just do it right from start and pads will work better and make less noise. On other brakes, sram, shimano for example I've ignored bed-in procedure and not had a noise problem but not magura. Once a rotor starts to squeal, even with new pads an improperly bed-in rotor can continue to squeal, don't wreck your rotors too. Always always always bed-in per instructions.

"New brake pads and rotors only reach their full performance during the break-in period. To bed in your pads, find an area with even ground and accelerate to a speed of 30 km/h before braking to a standstill. Repeat this process at least 30 times per brake.

Please note that larger rotors will extend the break-in period. Larger rotors with higher mass take considerably longer to reach the required temperature needed to fully bed in the brake. Lighter riders may be unable to properly bed in their pads and rotors on larger diameter set-ups. FAQ: Rotor Size:

larger rotors combined with lower rider weights generally extend the break-in period required for the pads and rotors to develop full power. It can even be impossible for riders weighing under 70 kg to effectively bed in their brake pads with a rotor diameter larger than 180 mm, due to the pads and rotors not reaching the necessary temperatures. A lack of braking power or increased noise levels are often caused by brake pads that have not been fully bed in and/or by set-ups that don’t reach the necessary temperatures during use for the pads to be “cleaned” regularly. Pads and rotors that have not been properly bed in won’t reach their optimal performance and wear will increase"

 

[p3eps]

I normally go for 15 to 20 Bed in stops.
Have you tried straightening your disk?
I have successfully straightened disks with the Parktool DT-2C

The rotor is about 2 and a half years old, so spending £25 on a new one isn’t too much of a hardship. I’d be scared I made it worse or couldn’t make it any better by attempting to straighten it!

 

[p3eps]

It's been over a month, but here's a further update on this saga!!

The new rotor arrived, and was checked by the Metrology guys to be perfectly straight. I fitted it to the wheel, aligned the caliper - and was met with the same issue. As the wheel spun, I'd get a pffff noise every rotation. I spent an evening trying to align it, and was still failing. A guy at work suggested putting Coppaslip on the backs of the pads to reduce the vibration. It made no difference.

Not usually one to admit defeat, I booked it in to the LBS, and dropped it off.
Collected it a couple of days later, and the tech spun the wheel for me. It's still the same I said. No it's not. Ohhhh yes it is, Ohhhh no it's not. When I raised the front wheel to head height and spun it - he then agreed!
He got it on a stand there and then, and had the wheel off, the caliper loose - and within about 20mins he had it good. He advised the Coppaslip was a mistake, and I'd have to replace the pads.

I took it for a wee ride that weekend - gentle one around some tame trails as I was going on holiday on Thursday. Front wheel got away from me when going along a wooden path - resulting in some big bruises, bleeding and broken ribs!! My wife was well pleased when I arrived home knowing she'd have to entertain the kids for 10 days!! I did manage to clean the bike before going though.

It sat untouched for nearly 3 weeks. When I spun the front wheel, it was back 'singing' again with a slight whine. I knew that if this got wet, it would shriek like a banshee!!
I decided to fit the 2 new Michelin Wild's I'd bought a few weeks prior. A bit more painful than I expected, but got them both on. I also fitted the new Galfer brake pads I bought too.
Funnily enough, the brakes rubbed like hell when I put the wheel back on.

Lots of adjustments, and no success - I tried taking the pads out and aligning the caliper in the centre.

As you can see - the rotor is slap bang in the middle of the caliper from the top / bottom spacing. When I spun the wheel, there was absolutely no movement from the rotor - it was completely true.
Popped the pads in, and there was that lovely whine again.

It was a nice day, and I was fed up by now, so I decided to take the bike for a spin anyway. Still injured, I just cycled round roads and cycle paths to avoid any excessive bumps! The brakes came and went.... but the noise was probably shrieking more than it wasn't! I turned the volume up on my headphones and shut it out - and made sure I gently held the brake lever when approaching humans as that killed the noise!!

I called my LBS again, and advised I was having the same issue - and the first appointment is this Monday (14th)... so I booked that.
In the meantime, the in the wonderful world of Facebook, I got a targeted ad (they're listening I tell you!!) for a device called a Cycle Pal. A small piece of metal for £15 that helps align brake disks. Lots of positive reviews, so I thought 'why not'!!. It's designed to sit over your rotor and be put into the caliper (with your caliper loose). You then pull your brakes and tighten your caliper - ensuring it's in the correct place.

The Cycle Pal was delivered within a couple of days, so last night I tried it. The spacing in the Maguras is so tight, I couldn't even get it in! I took the pads out, and then slid the Cycle Pal into the brake. I then re-fitted the pads - which was a bit of a squeeze. Held the brake lever, and then tightened up the caliper. I spun the wheel, but the Cycle Pal was stuck! I manage to get my finger on the end of it, and spin the wheel to pull it out.
Moment of truth - I gave the front wheel a giant spin... and it was SILENT!!!!

My ribs still aren't great, but I'll try a gentle ride on the bike at the weekend and see how it is. Hopefully the Cycle Pal has solved my woes! I'll keep my LBS appointment open for now - but if all is well on Saturday, then I'll be cancelling it.
I'm not going to rave about the genius of the Cycle Pal yet... but it may turn out to be £15 well spent!!

 

[VWsurfbum]

So you're saying that the pad gap/travel to the rotor has been the issue?
This will return as soon as the pads/caliper go back to the position they are designed to sit (the movement of the rubber seals)

 

[p3eps]

So you're saying that the pad gap/travel to the rotor has been the issue?
This will return as soon as the pads/caliper go back to the position they are designed to sit (the movement of the rubber seals)

The warped rotor was the first issue... but then it sounds like I'm just having a lot of difficulty lining it up.
I did a we ride round the block last night, and it seemed fine after using the brakes multiple times.

Time will tell.

 

[p3eps]

@p3eps sounds like it’s time for some trickstuff.

Which ones though?! I've had Galfer and Nukeproof in the last year - but always go with Sintered as they claim to be best for wet conditions. Where I live, it's usually wet conditions!!

 

[Eliadn]

Perhaps ignore the sound? I for sure do after centering the caliper

 

[p3eps]

Perhaps ignore the sound? I for sure do after centering the caliper

A bit like nails down a blackboard - it was soooo loud!!!

 

[squeegee]

Welcome to Magura Hell. If there's anything Magura needs, either design in more pad clearance or use pad springs to aid retraction, like most other brands of brakes. Also a system that isn't so adept at trapping air when bleeding.

I have 2 sets of MT7 on 2 bikes I ride regularly. I find it shear luck if at least one brake isn't making some kind of squeal. I've been running these brakes for 3 years and all of the problems are just commonplace, just look it up, tons of reports of this.

It's not you, it's not the LBS, it's Magura. They need to refine the design to make life easier on us. Sooner they admit to the flaws, the better. I keep running them for a few reasons:

1. I own 2 sets, have a spare, have multiple rotors, bleed tools and lots of royal blood.
2. The feel of Magura brakes is ideal to me, power comparable to Saints but with excellent modulation.
3. Consistent bite point, no wandering levers, i.e. wandering pistons. Never mushy feeling like some SRAM models.
4. Interchangeable lever blades--this is huge to dial in your own personal ergonomic preference.