Magura brakes barely stopping me (brand new)

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Magura brakes barely stopping me (brand new)
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flag Stumbows
Posted: Mar 16, 2020 at 0:57 Quote
End of last year bought a new bike that came with Sram Guide T's pre-fitted on 160mm discs front and rear.

Having being somewhat disappointed with the stopping power of these brakes I decided to do some research and found that for the money the Magura MT-5's about the best brakes you can get. I ended up opting for the Trail Sports which is MT-5's up front with MT-4's at the rear but with the MT-7 levers which is what I really wanted. Prefer the one finger braking.

However after fitting them up and bleeding them and running through the bedding process for what should definitely be long enough I am so disappointed.

I can't lock my back wheel up at all. Instead smoke starts pouring off it from the friction. It just won't grip hard enough. The fronts are only marginally better and the whole system feels lack-luster from my expectations. I don't know if I am doing something wrong or what?

All the reports online made me feel like if I wasn't careful I could end up over the bars given the braking power of these things. But this could be not further from the truth. Now I am scared to ride with them in case I need to pull up quickly.
flag cmcrawfo
Posted: Mar 16, 2020 at 1:09 Quote
Sounds like pads and/or rotors are contaminated.
flag Branmuffin
O+
Posted: Mar 16, 2020 at 13:34 Quote
Stumbows wrote:
End of last year bought a new bike that came with Sram Guide T's pre-fitted on 160mm discs front and rear.

Having being somewhat disappointed with the stopping power of these brakes I decided to do some research and found that for the money the Magura MT-5's about the best brakes you can get. I ended up opting for the Trail Sports which is MT-5's up front with MT-4's at the rear but with the MT-7 levers which is what I really wanted. Prefer the one finger braking.

However after fitting them up and bleeding them and running through the bedding process for what should definitely be long enough I am so disappointed.

I can't lock my back wheel up at all. Instead smoke starts pouring off it from the friction. It just won't grip hard enough. The fronts are only marginally better and the whole system feels lack-luster from my expectations. I don't know if I am doing something wrong or what?

All the reports online made me feel like if I wasn't careful I could end up over the bars given the braking power of these things. But this could be not further from the truth. Now I am scared to ride with them in case I need to pull up quickly.

100% they are not functioning correctly. These brakes are notoriously difficult to bleed but they are great once you get a solid bleed. Definitely sounds like you have a leak or air in the lines or both.
flag Dkutassy
Posted: Mar 17, 2020 at 3:51 Quote
You definitely contaminated the brake pads/rotors with something. By your description you bathed your brakes in brake fluid.

I would say you need new pads and rotors at this point.
flag cmcrawfo
Posted: Mar 17, 2020 at 6:42 Quote
There are several ways to decontaminate pads and rotors.

Fire, boiling, sanding .... combinations of these ... probably other tricks if you look hard enough
flag onyxss
Posted: Mar 17, 2020 at 6:47 Quote
cmcrawfo wrote:
There are several ways to decontaminate pads and rotors.

Fire, boiling, sanding .... combinations of these ... probably other tricks if you look hard enough
If oil contaminated pads and it went deep down, nothing will help. Same for glazed rotors.

All of those "decontamination" methods always ended the same way for me - ton of wasted time. Now i do it more efficient way - if contamination appears, i change rotor+pads and save me a lot of time and nerves. Pads can be quite cheap these days. Big Grin
flag cmcrawfo
Posted: Mar 17, 2020 at 6:52 Quote
onyxss wrote:
cmcrawfo wrote:
There are several ways to decontaminate pads and rotors.

Fire, boiling, sanding .... combinations of these ... probably other tricks if you look hard enough
If oil contaminated pads and it went deep down, nothing will help. Same for glazed rotors.

All of those "decontamination" methods always ended the same way for me - ton of wasted time. Now i do it more efficient way - if contamination appears, i change rotor+pads and save me a lot of time and nerves. Pads can be quite cheap these days. Big Grin

I disagree based on my experience. That said I probably haven’t submerge my pads rotors in fluid like some.
flag Dkutassy
Posted: Mar 17, 2020 at 13:51 Quote
cmcrawfo wrote:
onyxss wrote:
cmcrawfo wrote:
There are several ways to decontaminate pads and rotors.

Fire, boiling, sanding .... combinations of these ... probably other tricks if you look hard enough
If oil contaminated pads and it went deep down, nothing will help. Same for glazed rotors.

All of those "decontamination" methods always ended the same way for me - ton of wasted time. Now i do it more efficient way - if contamination appears, i change rotor+pads and save me a lot of time and nerves. Pads can be quite cheap these days. Big Grin

I disagree based on my experience. That said I probably haven’t submerge my pads rotors in fluid like some.

If he got the rear brake smoking whole trying to bed in the pads I'm thinking those pads and rotors are beyond saving.
flag R-M-R
Posted: Mar 17, 2020 at 17:13 Quote
Something is clearly wrong. The four-piston models should be on par with other four-piston brakes. Two-piston Maguras are not particularly strong.
flag seismicninja
Posted: Mar 17, 2020 at 20:30 Quote
Try cleaning the rotors with isopropyl alcohol and take the pads out and rub them on sand paper in a figure 8 pattern. Definitely sounds like whatever is on the rotors is burning. MT5'S should lock the front wheel easily.
flag R-M-R
Posted: Mar 17, 2020 at 21:04 Quote
Agree, but take it a step further with acetone and also sand the rotors.
flag Stumbows
Posted: Mar 19, 2020 at 3:47 Quote
Just had a chance to take everything apart this afternoon and see what's going on. The rotors and pads a definitely contaminated. I didn't think I got fluid on them during the bleed but I must have. Going to order some new ones online. It's only the rear at the moment as the fronts didn't need bleeding because I didn't have to disconnected anything to fit them. Although since the bleed of the rears they do feel better level feel wise. So it might be worth doing a front bleed but I will certainly do things a little differently this time around.
flag seismicninja
Posted: Mar 19, 2020 at 4:09 Quote
seismicninja wrote:
Try cleaning the rotors with isopropyl alcohol and take the pads out and rub them on sand paper in a figure 8 pattern. Definitely sounds like whatever is on the rotors is burning. MT5'S should lock the front wheel easily.

No reason to order new ones. Just do this on front and rear. You may not have spilled anything on them but having oil on your hands and touching the surfaces can contaminate them easily. Like I said before, the MT5 in the front should stop a freight train so definitely worth cleaning and doing the bed in again.
flag freerider11
O+
Posted: Mar 19, 2020 at 5:14 Quote
IME once pads are contaminated, it's nearly impossible to get them good as new again. Sure, you can make them better by cleaning with iso and sanding them down, but I don't think I've ever got them feeling as they should again after contamination. Pads are relatively cheap so to save the headache, just get new ones.

Rotors you should be able to salvage though. The process that's worked great for me in the past is to remove them from the wheel, give them a good wash with water and dish soap. Then give them a good wipe down with a clean paper towel and 99% iso alcohol. Then a light sanding with (clean) emery cloth (sanding in a circular pattern all the way around the braking surface of the rotor). Then another wipe down with iso. They should be good after that.

Once you have new pads and a salvaged rotor, a good trick to aid the break in process is before installing the pads, get them wet and rub the 2 pads together for 30 seconds, then rinse off again and install. They seem to bed in much quicker after doing that.
flag onyxss
Posted: Mar 19, 2020 at 7:26 Quote
Stumbows wrote:
Just had a chance to take everything apart this afternoon and see what's going on. The rotors and pads a definitely contaminated. I didn't think I got fluid on them during the bleed but I must have. Going to order some new ones online. It's only the rear at the moment as the fronts didn't need bleeding because I didn't have to disconnected anything to fit them. Although since the bleed of the rears they do feel better level feel wise. So it might be worth doing a front bleed but I will certainly do things a little differently this time around.
Bleeding next time:
-use gloves
- remove wheel, put it at least 2m away from bike
- remove pads, put them 3m away and use bleed block.
- Clean calipers and around with isop. alcohol after done with bleed
- remove gloves
- install back wheel + pads, don't touch pad surface or rotors
- congrats, you have done contamination free bleed Big Grin
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