Magura MT8 leaking
One of my MT8's is leaking behind the master cylinder where it mounts to the bars. There's a tiny hole there and the fluid I is squishing its way out. What is this hole for and how can I fix this?
Sent from my Xoom using Tapatalk 2
I think that's a weep hole. I had that when I first installed my MT8s. Remove the lever and clean it up.
If you have an early version, it was possible to have the mounting stud un-thread while removing the clamp nuts. The studs actually clamp the red cover to seal the master cylinder. If this is a new problem and you just happened to remove the clamp or loosened it for any reason this might be your problem. You can double nut the stud and re-tighten to seal it. I can tell you this too, I still heard the "squishy" sound for a couple of days after I tightened it because of the fluid that was already trapped between the gasket and cover. This is all first hand experience I have had with my set, not guessing. I hope it helps.
Magura USA told me that they have an updated the design slightly to fix this. I have a new design and an old design, but by looking at it, I can not tell the difference.
Thanks for the info. It is an old version so I'll try that trick.
Sent from my Xoom using Tapatalk 2
BPD 131 is correct (thanks BPD) that the hole is "as designed" a weep hole for atmospheric pressure changes which allow an area for expanding fluid when heated and also to allow the automatic pad wear adjustment feature of all modern hydraulic brakes.
If there wasn't a "weep" hole, think of the thumb over the end of a straw as it will hold the fluid in the straw until uncovered, then the fluid will be released.
The weep hole allows this fluid to drop and to allow the brake pads to always self adjust due to pad wear so the engagement point (lever contact point) stays the same.
So, Your fluid evidence is most likely from the bleed process and not a leak. As BPD mentioned, the early designs had a "triangulated" posts that provided a natural hardware locking feature and is common on all designs coming out of Germany for autos and motos but we have changed this quite awhile ago.
Even so, If you have an early design, Its repairable like BPD states by locking two nuts together and re-tightening the stud but this may not be your issue.
I find on every bleed (due to the 45 degree MC position we recommend) allows any residual fluid from the MC bleed port after removing the syringe to run down the MC body directly to the clamp back plate/handlebar and can work its way in between the bar and weep hole.
The fluid can then position itself right in this junction and cover the weep hole slightly and when you pull the brake lever, the bladder inside the MC slightly pulses and can push and pull the residual fluid making this "squish" sound. Think of a squirt gun.
There is nothing to worry about as it will not adversely affect function but if it bothers you, like BPD stated, remove the MC and just wipe the residual fluid clean.
Let me know if there is anything more I can assist with. Don't hesitate.
Thanks for your patience!
If cleaning up around the weep hole doesn't fix the issue, then maybe you should look into that. It's likely just a bit of oil around the weep hole causing the issue. No need to overthink it. My advice came from first hand experience as well, BPD...
Originally Posted by Alexgonzalezmi
I was not insinuating otherwise, nor did I have your post in mind when typing that. In fact in your post you stated that it happened to you and your set during install. Sorry if you felt it was direct at you or your reply. I was simply trying to provide an example of what did happen in my case which was in addition to your find.
Originally Posted by ncfisherman
All Good BPD, no worries and thanks for your expert comments and assistance!