Magura MT7 leaking in Master Cylinder


Active member
Feb 27, 2019
I have the Magura MT7 and 400Km ago I bled the rear brake, but yesterday the lever was soft and close to the handlebar again. Checking the lever I saw that it was stained with a thin layer of brake oil.

On the side of the lever there is a small hole that if an internal joint breaks, the liquid will spurt out, but that's fine.

I rather suspect the U-Cup Seal in the "Master Cylinder" and the piston. Searching in Google I have seen some cases of liquid loss because the piston "U-Cup Seal 6x10x3mm" got damaged, I attach to a couple of pictures from a USA forum

So I have two options:

OPTION 1.- Buy a MT5 Master Cylinder (Cheaper than MT7 but compatible, looks like the only difference is the lever) ) and install in new MT5 Master body the old MT7 lever.

OPTION 2.- Buy the U-Cup Seal, remove the piston from the Master Cylinder and change the seal.

Now the question: Has anyone removed the piston, is it as easy as removing the lever and pulling the piston out, changing the seal and putting everything back?

Magura Piston.jpg Magura Junta UT.jpg
Last edited:


Active member
Jun 26, 2022
Fort William
I love my Maguras but they have to be the cheapest made brakes I’ve ever used! I have them on 3 bikes, all but one of those has been converted to the “shigura” set-up because of leaky master cylinders.

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