is there a Magura Brake expert in the house?

[tillson]

I have always been a fan of Magura rim brakes and still am. But there is a slightly annoying problem.

On my front wheel, which is now perfectly aligned in the forks, one brake pad is skimming the wheel (RHS), whilst the other pad is a short journey away.

I have backed the adjuster right off and painstakingly set the same gap between pad and wheel on both sides. When I increase the adjuster, I expect to see both pads move towards the wheel together. The gap between pad and wheel decreasing by the same amount on both sides with each turn.

What actually happens, is that only the right hand pad moves towards the wheel when I turn the adjuster. The left hand one remains stationary. This effectively puts the wheel off centre relative to the brake pads.

When I apply the brake, the left hand pad (the one furthest away) moves first until it touches the wheel, and then the right hand one takes up the remaining slight gap and the brake is applied.

Close examination shows that the adjuster only has an effect on the right hand side of the brake mechanism. Whilst the brakes still work, this seems rather strange and I wondered if anyone else had experienced it.

Is this how they are supposed to work? Or is there some kind of balance mechanism?

Thanks for any help you may be able to give.

 

[NRG]

I'm no expert tillson but have these on my PCS and both pads move at the same time. I wonder if you have a leak somewhere and air has got into the line....

 

[Cyclezee]

Just a thought Tillson, could be air, and bleeding the system might just cure it.
Ideally you need a Magura bleed kit and Magura Royal Blood. If you Google, you will get the best prices.

 

[tillson]

Thanks Aldby and NRG, I think you both might have something there

I remember now that both brakes were delivered with very long hoses attached. The rear brake works fine and that was fitted, as delivered, with the full length of hose attached. I had to cut the front brake hose to a shorter length for obvious reasons. That probably resulted in air getting into the system. I didn't bleed the brake after cutting back the hose.

I'll order a kit and fluid as suggested and give that a go.

 

[mutmost]

Hi,
it is worth a read or possible a post on the magura forum as they have a lot of info and help, could be a sticking cylinder.

MAGURA Community

 

[tillson]

Thanks for the Magura Forum link. I've posted a question, but the forum doesn't look as though it has many subscribers. I think some Magura employees monitor it, so i might be lucky.

 

[tillson]

I've had the following reply from Magura regarding the uneven brake adjustment problem. I had hoped that this wouldn't be the answer.

The brakes are very good, but to have this adjustment flaw in their design is a bit silly. With hydraulics, it would have been so easy to have designed this out.

Hi Thomas,

The effect your getting on your brakes is caused by the slight differences in friction from one side to the other. One seal will, (almost), always have slightly more lubrication, or the seal will be a thousandth of a millimeter bigger on one side than the other which will always allow one side to move first. The prinicpal of Hydraulic force is that the pressure will always be balanced. However at the start of the movement, like a river, the oil will always take the path of least resistance, this in your case is the right hand side. You can balance the cylinders by holding the side that moves the easiest with your fingers and pump the side that is slowest to move. This will have the affect that the seal that is slower will get a bit more lubrication and or will help clean any debris that may be blocking it slightly.
Although this should help it can often be short lived as the seals can very easily become unbalanced again. The pressure on the rim however is, in the normal state of affairs always constant, the amount of force needed for the second piston to move after the first has touched the rim is minimal to nothing, and the force exerted on the rim should then be equal on both sides.

I hope this helps in some way.

Regards,

Drew *



Drew Coull
UK Sales Support Manager