Avid Elixir 5 brakes losing pressure and excessive pad wear

Obs1dian

I have recently bled my Avid Elixir 5s and they were working rather nicely for quite some time and for a good 30-50 miles (really don't know exactly how far I rode since bleeding) with no problems.

However, I've just completed the Wiggle Southern Rough Ride and have 35 miles (actually during the course) I noticed that I lost a bit of pressure in my brakes meaning that the levers went in to the handlebars a lot more than when I started. Why is this? I'm thinking that there may be a bit of air in the line but it happened on both brakes by about the same amount.

One other question I have is that my front disc is wearing a rather deep groove in to the pads (the rear does not do this) - is this normal and if not, what can I do to stop it?

Many thanks in advance!

ricardo_smooth

lever travel will be pads wearing creating more lever movement. groove in your pads means there is either something stuck in the pad or there could be damage to the disc. pop the pads out and have a look. rough the pad surface up with some sandpaper and see if the groove appears again or if a stone or something ended up being chucked through it.

bluechair84

I had this on a Hayes 9 a number of years back, I never figured out what happened though I hadn't even bled the brake prior to that. It was just a fine brake until one day - gutless.
A bleed after that solved the problem though, so try re-bleeding. I wonder if it's an air bubble in the lever that has worked it's way into the line, (though my knowledge of lever architecture is slim, I think there is a reserve which allows for piston adjustment and expansion. If the bubble was in there it might not affect the performance until it works it's way out into the line).

Groove in the pads = check the rotor.

Obs1dian

Okay so I've put bleed blocks in and the levers are now rock solid - is there a way to get some sort of middle ground with the lever feel? They're far too soft with the pads in (and the pads have plenty left in them).

The groove in the front pads is very large - I have noticed that there is a smaller groove in the rear pads. It's as if the pad is contacting the top of the rotor first which is then digging in to the pads, as if they are slanted - almost forming a pyramid as they touch the pads if that makes sense?

bluechair84

Well, with the blocks in place you'd expect the levers to be solid. If there was a bubble in the line then it would still be soft. I'd go with Ricardo on this one and assume the pads were low.

As for the pyramid shape in the pad's; do you have wavey rotors? I find they give an uneven wear rate across the pads.

nicklouse

sounds like you just need to let the pistons reset them selves. try adjusting the lever reach.

Which is what i would have done first time around as pads do wear changing the lever position.

mattv

Sounds to me as if the calipers are not parallel to the disc. Could be many things causing it, including a stick piston. This causes the other pad to move twice as far, bending the disc and making it feel spongy. Also, this allows the top of the disc to groove the pad that is stuck.

Obs1dian

Well I've just stuck new pads in the front which seem to have sorted out the spongy (moving in toward the handle bar too far) feeling. The stuck piston thing is interesting as the groove is worrying. How would you fix "stick piston"? Is there anything to look out for.

Nicklouse - lever reach did sort out the spongy feeling to a certain extent but it seems that the groove is where the pads are contacting the disc rotor most (possibly this seems obvious!) therefore new pads have fixed this.

It also seems that my pads don't last very long - I had sintered on the front and whatever the standard Avid pads are on the back. The sintered ones don't seem to have lasted much - possibly 100-150 miles.

What is the average life of a set of pads anyway? I imagine this is affected by how you ride. Personally I ride a lot of XC/singletrack but I'm also quite aggressive and tend to come close to what I imagine is downhilling (depending on the trail of course).

Squarepants

Obsidian Blackbird McKnight - not sure if this will help but I really firmed by 5's up by setting the deadband (the amount the lever moves before it activates braking) by whipping the wheels off and pumping the pads in with the lever until they're about 1mm apart, slide in the bleed blocks to push the pads apart (but not all the way - this a suck it and see/trial and error procedure) and you should be able to set them until they have almost 0 movement in the levers before they bite.

Then tri align them again (undo caliper mounts, pull and hold lever whilst tightening up caliper bolts to ensure the caliper is 'square' on the disc) and bolo's your familiars uncle