Hey, had a quick question about my Magura rim brakes.
Went for a ride today and didn’t have any issues with them. I didn’t use them a whole lot, but when I did, they were working just fine.
Came home, leaned the uni in my room for a few hours, and then went back out to ride in the driveway for a few minutes.
Took it out to the shed because I wanted to adjust my brake lever a bit, and began playing a bit with the set screw on the bottom of the lever.
Next thing I know, both my pads will come out when I squeeze the lever, but only one will retract back in. Haven’t played with the red knob on the lever, and cannot detect any leaks.
Has anyone heard about this? Is there something obvious going on here? Right now I’m freaking out because I’ve got some rides planned and would enjoy having my brake.
I did PM Brycer about this as well. Just wanted to broaden my range a bit.
I’m hoping someone out there can help me because I don’t want to have to take this to the bike shop unless it’s absolutely needed.
I sent you a PM as well
If you screw that set screw in (clockwise) , it drives the lever piston in, which pushes the pads out toward the rim. (The red knob effectively does the same thing, but is adjustable on the fly as you ride.) When you drive that set screw in, it creates some “float” in the system and its totally fine to ride this way. Also, its common for used and even new rim brakes to have one side that moves out first and then the other side quickly catches up as the brake lever is cycles further.
Its fine to leave the set screw in so the lever is easier to reach (its the way I ride too). If you find that either brake pad rubs the rim now when you re riding or idling, you might have to loosen the brake mounts for the slave cylinder that has its pad closest to the rim and move that slave away from the rim just a bit to compensate for the set screw change. make sense?
What would unicyclist do with out Bricer?
Sometimes the slaves get sticky, make sure there’s not a bunch of grit on the poston, maybe clean them with brake cleaner spray.
This is one of the PITAs with Maguras, they do the one side action thing, gets old, esp if you ride off road and get them nasty.
I may have to try that. I’ve got them to where the uni is rideable, and I the brakes are working, but one pad is still not completely in the cylinder and I worry they’ll stick when I’m on the trail…
Thanks for the help guys.
One caution: some brake cleaner will remove some of the Magura powder coating colors or damage the o-rings in the slaves. I use rubbing alcohol as a solvent for cleaning the slave cylinder pistons. Q-tips work well as a cleaning tool.
PM Sent. Here’s some pics… Left pad is all the way in, right pad is out a bit.
Make sure that the red knob is dialed all the way out and the set screw on the lever blade tip is out as well. If you checked those, there is likely a little bit of air in the system causing that problem. A bleed should fix it. If it works normally except for the full retraction issue, then I’d just ride it as is.
While an air free brake bleed provides the crispest feel at the lever. the way that most unicycle riders use Maggies, they will work just fine for drag brake purposes going down big hills with a fair ammt of air in the lines (though I don’t recommend it if you have the tools to bleed it and get rid of the air).
Bikers and trials bike riders particularly require a super firm lever feel, air free brake bleeds and use Maggie rim brakes for hard stops and apply tremendous force at the lever to hop around on the rear wheel and climb rocks, etc.
With the set screw backed out and the red knob in, I can push both pads in all the way, but when I pull the lever, the pads come out, but the one still doesn’t go all the way in.
If this is gonna need to be bled, I’ll have to think on the bleed kit for a while. Not sure if I want to ride it the way it is or bleed them.