Does my brake line need to be bled?

After a drop on my Muni, the handle on my Hs33 brake bent and needed to be replaced. I replaced it this weekend, but now the brakes don’t seem to be as strong.

I looked in the owner’s manual and the only reference to telling if the brake line needs to be bled is something like: the calipers will not move inward when you gently pull on the lever.

When I pull on the lever, the calipers move. If it needed to be bled, would the calipers even move?

When I was changing it, there is a pinlike thing that dangles from the handle that works like a plunger and it came out, but the rubber seal that it goes into stayed intakt.

tough nuts.

EDIT: :roll_eyes: , but really, I have no knowledge on the subject of brakes :roll_eyes:

They shouldn’t need to be bled if you didn’t lose any fluid. It may help to adjust the knob on the lever. The knob on your original lever may have been at a different setting, thus placing the pads closer to the rim and seemingly having a firmer feel :smiley:

It doesn’t happen often, but it is possible for the piston that the little rod goes into to pop up and leak fluid out, or air in. If it sucked in a little air, you will need to bleed it to get the “spongy” feel out of it. Bleeding instructions are at : Magura Cult

The easiest way to avoid that happening is to use something to hold the piston down while changing the lever. The method I use is in the attached photo.

Quite possibly you need a bit more fluid in there. If it takes more lever movement than before to have the pads actually start moving, or if the lever feel is real squishy instead of firm when the pads contact the rim, then you probably have some air in the system. The good news is that bleeding needn’t be as complicated as they say.

What I do that works great is position the uni so the bleed hole in the master cylinder is facing up (the seat front will be pointed down). Then just take that screw out (nothing will leak out), and add fluid until it’s full. Add a little bit at a time, then GENTLY work the lever to push the bubbles out the top, breaking them as they surface so as not to let fluid spill out. Sometimes, slightly shaking the lever will help dislodge the bubbles so they rise. Then when you can’t add any more fluid, put the screw back in. The brakes should now work with a firm lever feel.

So long as the only air is up in the master cylinder area, this method should work.

Another thing to check is whether you’ve got some leakage around the piston seal area. I’ve had 2 masters now that have developed leaks and needed to be warrantied. So far, I’ve had no luck fixing them by replacing the o-ring inside. Maybe someone else knows how to make these things work again, but I haven’t succeeded yet. Fortunately, Magura has been great about supporting their product (which isn’t supposed to leak for 5 years).

Hope all this helps!

Jerry

When you bleed it, be sure the TPA knob is screwed all the way down so the rod and piston are fully retracted. Otherwise you will lose travel because there will be less fluid in the system.