MT7 brake grumbling noise

[Just get out there!]

I just resolved this problem by having my brake mounts and adapters re-faced using a Park DT-5.2 refacing tool. I sent a similar video to the one in this thread to Magura. One of their techs told me they run into it a lot and it is caused by the brake post mount surfaces not being flat and perpendicular to the rotor. I've got a 2021 Turbo Levo running MT7's and 220 Magura MDR-P rotors. When I checked the mounts with a flat piece of machined metal, they were WAY off plane from one another and rounded a bit. I think the whole caliper assembly was flexing quite a bit when I'd apply the brakes heavily going down a steep trail. Couldn't get them to repeat that sound on the rack or on the flat. Had front and back re-faced and like magic, no more noise. Set me back $300 USD to have it done but it was well worth it. If I had it to do over, I'd buy the tool and do it myself, then hit my buddies up for a bit of compensation if they want to reface their brakes. I love my Turbo Levo, but in my opinion the mfg's should be facing those post mounts at the factory when they're charging $10k USD +/- for their bikes. Mine came with SRAM codes and they howled like banshees on long descents. Now I know why. The bang, bang, bang sound was a Magura thing.

Bottom line: Reface your brake mounts, and your adapters if needed (I think they can deform if the mounts aren't flat to begin with), do a full go through on your brakes to make sure the pistons aren't sticking and that they're bled and aligned correctly, bed them properly (big Magura's take a lot of bedding so do it their way), and I'd be willing to bet you won't have that sound any more. Also, the magura MT7's are hands down the best brakes I've ever used (they just don't play well with out of true post mounts). Hope this helps!

 

[Just get out there!]

Take the pads put of the caliper.
Align the disc centrally to the caliper, this has to be 100% not 99%.
Make sure pistons are equally pushed back.
Insert pads and give it several big squeezes.
Job done.

The Maguras have to be 100% aligned or they will grind under heat/pressure.

It took me several attempts to get it right, be patient.

It is worth dropping the wheel and inspecting the pistons by squeezing lever gently to see if all 4 pistons move equally. There's a guide on magura website for sticking pistons and how to release them. Be careful not to over extend the pistons.

Spot on (all of it). But have your brake post mounts refaced with a Park Tool DT-5.2. Whatever you don't even think about doing it by hand with a file. See my post later in this thread regarding how I successfully resolved my Magura problems.

 

[Just get out there!]

Similar issues. Sent video to Magura tech and was told there's an alignment issue and the mounting posts need to be re-faced. Waiting for refacing tool to come in so I'll see how it goes.

Refacing did the trick. Night and day difference. Also mobilized the pistons really well and made sure they were pressed back and bled properly. Need to get the alignment just right on these things or you get the dreaded sound. If you look closely with the pads removed, you'll see there's a section of the caliper that runs really close to the rotor. Hard to see if the pads are on. I found that if you use the yellow blocks with the pads removed to get the calipers initially aligned with the rotor, then visually check for even gap from that closer metal part of the caliper to the rotor, then install the pads, then fine tune as needed it works pretty damn well. Just keep in mind that you'll never get there if your caliper mounts aren't flat and true in relation to the rotor, so reface, then do the other stuff and you'll probably win in the end.

 

[slay]

I did have the mt7 for last few months and they was makeing crazy grinding noise,
Finally problem sorted, change the brake pads for aztec organic, they got smaller pad area and therefor they won't go in to the rotors air vent holes.
Dead silent brakes finally...

You can see in the picture that original mt7 pad corner did rub in to the vent holes.

 

[All4Fun]

I did have the mt7 for last few months and they was makeing crazy grinding noise,
Finally problem sorted, change the brake pads for aztec organic, they got smaller pad area and therefor they won't go in to the rotors air vent holes.
Dead silent brakes finally...

You can see in the picture that original mt7 pad corner did rub in to the vent holes.

If i see the wear on the pad, i would say bad alignment.
There are 3 bikes here with Magura brakes, 2 and 4-piston models, only original parts and without problems.

 

[slay]

You wrong, they are checked by 3 shops, aligment is perfect...
That's very well issue with mt7s and 220 discs.

 

[All4Fun]

You wrong, they are checked by 3 shops, aligment is perfect...
That's very well issue with mt7s and 220 discs.

2 bikes, front and rear 220, MT7, no problem.

Btw, checked by 3 shops says nothing to me, even then is misaligment possible, the wear on your pad is uneven.

 

[slay]

What wear ? They are new, was on bike, made grinding noise, exchanged for azrecs , all good.
Just check on the google, mt7 and 220 mdrp disc problems, you will be surprised.

 

[All4Fun]

What wear ? They are new, was on bike, made grinding noise, exchanged for azrecs , all good.
Just check on the google, mt7 and 220 mdrp disc problems, you will be surprised.

Well... i guess, i'm one of the lucky few....

 

[slay]

Well... i guess, i'm one of the lucky few....

Yeah, for me was all good on the back, front was like ABS. I did bedding around 5 times with micronmetre plates and no changes. I would guess smth was wrong with the original pads.

 

[All4Fun]

Yeah, for me was all good on the back, front was like ABS. I did bedding around 5 times with micronmetre plates and no changes. I would guess smth was wrong with the original pads.

If something is wrong with the mounting posts, uneven layer of paint or so, the caliper is a bit tilted, that could be enough.
Did they check that at the shops, did they remove the calipers, or was it just a matter of loosening the bolts, pull the brakes and tighten again, with maybe a slight visual check after.

 

[slay]

They and me, took of mounting post, swapped for hope one, did try to put washers under e.t.c..
Now from original pads I just did swap them , no bedding or anything, and problem sorted.

 

[Just get out there!]

Resurface posts and spacers with a proper resurfacing tool IMO (think machine shop mentality, not hand file mentality). As for washers, I'd opt for dialing in the posts and proper spacers as they're more solid and less likely to have variances. I was blown away by how far off my factory posts and spacers were. They're either perfectly flat and true (in relation to your axle and rotor) or they aren't (and most probably aren't). That's not something you can accurately determine by eye. You need something that accurately indexes it to the planes of the axle and rotor. Once flat and true, it's just a matter of adjustment. Worked wonders on my Turbo Levo.

 

[Alain78]

I also have the MT7 brakes with 220 discs front and rear and the original pads. At one time the brakes were whistling a lot and I solved the problem by adjusting the brakes, i.e. clearances and alignment.
I spent some time because it's very sensitive and to find the right setting, but now I have almost no hissing noise.

 

[Stihldog]

The Magura MT7’s brakes are a great upgrade when setup and maintained properly. I’m no expert on these brakes but I’ve installed several sets over the past 4 years (6-7 sets). Most of my small circle of eMTB friends use them so we are able to exchange ideas and any issues when they arise.

Initial bleeding after installation will not free up all the micro bubbles. It takes a few bumpy rides before that happens. Then only a ‘mini-bleed’ (master cylinder) is necessary.

Bedding in the brakes properly is important. Don’t miss this step. I use Magura preformance pads (#2 of three types available). I have no experience with other manufacturers brake pads. I believe the pads are an organic/metallic mixture. Suitable for my type of riding.

We have all switched rotors to 220mm front and 203mm rear. The larger diameter rotor in the rear was just too much. A 203mm rotor in the rear allowed for a more balanced feel but the 220mm gave great braking power in the front. The difference was noticeable.

Calliper centering is critical and post-mount alignment is important. Machine the post if necessary with a proper tool. This can be important as your post adapters get taller. A nice clean flat surface can help keep things aligned and may reduce noises.

There’s a lot of good ideas posted here but my experiences with Magura MT7’s have been very good once I got it figured out.