Magura Louise Brake Lever

[Dalton2250]

Hi guys,

I wonder if anyone can help me with my Magura Louise 2008 disc brake system. They're fitted to my Focus Raven 2008 MTB.

I'll break it down by left & right so it's easier to digest -

1) Right brake - I can pull the lever all the way back to the handlebars. Please note that normally, a characteristic of these particular brakes seems to be that the levers do actually pull back quite far before coming into effect. However in this instance I can pull it all the way back & instead of springing back into it's original position, it stays pulled back unless I click it back into place. This obviously affects the effectiveness of the brake in general. Do I simply need to replace the lever? Only it wasn't replaced all that long ago really when I had the same problem!

2) Left brake - Lever positioning & everything is fine, but when I apply the brake, it causes most of the frame to vibrate quite a lot, which in turn seems to reduce the effectiveness of the brake.

Can anyone tell me what I need to do or have done? I've been thinking of replacing the whole brake system in the near future but I just mean is there something relatively simple I can do to alleviate these issues?

Any help would be most appreciated!

Cheers

Si

PS: If you need me to take pictures and post them too I'd be happy to.

[X-RAY]

not familiar with that lever, but i had a plastic lever that stuck like that. the bolt that it uses for a pivot was overtightened, pinching the lever.

[DaveM]

These are hydraulic? If so...
On the right lever it sounds like the first step is to bleed the system (remove air bubbles). If that doesn't cure both problems it could be a sticky caliper at the wheel or a sticky master cylinder at the lever. This can probably be addressed without complete replacement.

On the left, sounds like a bent or loose brake disc. Check your disk and pads.

[Dalton2250]

(03-10-2011, 03:23 PM)DaveM Wrote:  These are hydraulic? If so...
On the right lever it sounds like the first step is to bleed the system (remove air bubbles). If that doesn't cure both problems it could be a sticky caliper at the wheel or a sticky master cylinder at the lever. This can probably be addressed without complete replacement.

On the left, sounds like a bent or loose brake disc. Check your disk and pads.

Thanks very much mate,

I'm not that technically proficient when it comes to bikes but I'll try my best to use your suggestions!

Cheers

[GeorgeET]

Ye, try the easy thing first and loosen the lever pivot bolt. Make sure the travel screw is adjusted for very little play on top.Check if the lever moves freely.

Otherwise it sounds like your master cylinder piston is not returning.(usually there is a return spring) Is the wheel free when this happens?? If not than your MC is locked.
Bleeding is always good and may free up debris. Otherwise rebuild time.

AS per vibration which wheel is it?? Could be loose wheel bearings, loose brake disc or loose pads or caliper. Make sure everything is tight. If its front check the head too. Bleed anyway. Should be a yearly process.

Lots of videos on Magura site. Special bleeding tools needed. I got my syringe at a farm animal feed place.Although the Magura bleeding kit is a good investment if you got to have hydraulic brakes.

I can lock my old bikes cable rim side brakes and lift my rear wheel if I pull the lever too hard.

[Dalton2250]

(03-12-2011, 12:50 AM)GeorgeET Wrote:  Ye, try the easy thing first and loosen the lever pivot bolt. Make sure the travel screw is adjusted for very little play on top.Check if the lever moves freely.

Otherwise it sounds like your master cylinder piston is not returning.(usually there is a return spring) Is the wheel free when this happens?? If not than your MC is locked.
Bleeding is always good and may free up debris. Otherwise rebuild time.

AS per vibration which wheel is it?? Could be loose wheel bearings, loose brake disc or loose pads or caliper. Make sure everything is tight. If its front check the head too. Bleed anyway. Should be a yearly process.

Lots of videos on Magura site. Special bleeding tools needed. I got my syringe at a farm animal feed place.Although the Magura bleeding kit is a good investment if you got to have hydraulic brakes.

I can lock my old bikes cable rim side brakes and lift my rear wheel if I pull the lever too hard.

Yes mate, nice tips there, although most of it is pretty alien to me I'm afraid. I've still got to get the necessary tools to tighten or untighen any bolts at all. So I'm gonna get one of those Magura mutli-tool things & a service kit for bleeding. Once I've got my head around that I'll see if these problems persist.

The vibrations occur within the frame when I apply the left brake lever, whether I apply it hard or gradually.

There's some reasonable videos on the magura website, nothing too in depth though. At least there's a video for bleeding the system so I should be ok with that.

I'll let you all know how I get on. Cheers very kindly for taking the time to advise me brethren.

One love

[X-RAY]

assuming the left handle is the front brake(i think some euro bikes may be backwards),check your headset. if its loose it could give the vibration you describe.

[JonB]

^sounds about right.

I have a similar problem with mine. When the headset is tight it functions properly. However it quickly comes loose as the bearings are wrecked and I get those vibrations you describe. New headset time for me.

it is also worth mentioning now that Magura brakes run on MINERAL OIL, NOT BRAKE FLUID. Mixing the two results in dead seals, leaks and a very expensive and messy mistake. You will need some of this to bleed the brake, which you definitely need to do. LHM (brake fluid for certain types of Citroen cars) is mineral oil and is a cheap substitute (with no performance difference I've noticed) to the manufacturer-specific mineral oil (which costs £stupid.99 a bottle). It's exactly the same stuff in a different bottle (though normally a different colour).

[Dalton2250]

(03-14-2011, 09:57 AM)JonB Wrote:  ^sounds about right.

I have a similar problem with mine. When the headset is tight it functions properly. However it quickly comes loose as the bearings are wrecked and I get those vibrations you describe. New headset time for me.

it is also worth mentioning now that Magura brakes run on MINERAL OIL, NOT BRAKE FLUID. Mixing the two results in dead seals, leaks and a very expensive and messy mistake. You will need some of this to bleed the brake, which you definitely need to do. LHM (brake fluid for certain types of Citroen cars) is mineral oil and is a cheap substitute (with no performance difference I've noticed) to the manufacturer-specific mineral oil (which costs £stupid.99 a bottle). It's exactly the same stuff in a different bottle (though normally a different colour).

Yeah mate, I know it's mineral oil. They call it Royal Blood don't they. I'll definitely bleed the brakes no doubt, just need to pay attention to the Magura tutorial video & learn how to do it properly. As far as the vibrating goes, I'll check & and/or overhaul the headset, see if that works. If not, I'll try the thing DaveM said about a sticky caliper (not altogether too sure what a caliper is but again, I have what I think is the method to fix this from the magura website).

All's left to do now is to buy all the necessary tools & equipment! My mrs ain't too happy about how much my bike costs to maintain I can tell you!

Si

[JonB]

The caliper is the assembly on the end of the brake with the pads and pistons. The Lever is (obviously) the assembly with the lever blade.

Sticky pistons are a possibility given the age of the brake.
Best cure is to FULLY dismantle the caliper and remove the pistons (use an airline or a hand-pump to pop the piston out of each caliper half, wrap a towel round to avoid taking yourself out with a flying piston). Then clean it out and put some grease on the seals and reassemble (then begin the VERY lengthy bleed)

In a brake that uses brake fluid, you'd use DOT grease, as yours is mineral oil, I'd go into a garage and ask what grease would be appropriate for an LHM system and use that. Get this BEFORE you dismantle the caliper!