When to bleed MTB disc brakes?

jeepie

Checked the FAQs and could see that there is a section in there about cleaning brake pads, but nothing on bleeding brakes. Got my first set of disc brakes - Shimano M575 Disc Brakes. The front lever is now very loose (as shown in section 8. of this techdoc > http://techdocs.shimano.com/media/techd ... 677008.pdf) meaning you have to pull the brake lever to the handle bar before it operates, but it does still stop well.

I just would like to get advise on what to do. Does this mean that I need to bleed the air out and add more oil? Or could it just be that the brake pads which look OK need to be changed. I've changed neither the brake pads nor the oil before as this is my first set of disc brakes.

Bike has done 600 miles in all weather. At this point I've no idea of the regularity with which either pad changing or bleeding should be done, and whether either would fix the symptoms described.

Any advice appreciated.

Cheers

J

MountainPete

Does the lever repond to pumping? (pump the leaver and see if there is any change)

nicklouse

sounds like you need to adjust the lever reach or change the pads. (look at them}

bleeding is only needed when the levers are spongy.

maybe 2 to 36 years or if the fluid is boiled. but as above when the lever is spongy.

jeepie

Wow - pumping the brake handle seems to have done the trick. Many thanks Mountain Pete. I haven't seen this suggested elsewhere so thanks! Why does this work out of interest?

Cheers

J

nicklouse

Jeepie wrote:

Wow - pumping the brake handle seems to have done the trick. Many thanks Mountain Pete. I haven't seen this suggested elsewhere so thanks! Why does this work out of interest?

Cheers

J

if the lever is going firm after pumping then either the brakes do need bleeding or you have just reset the pistons/pads.