Avid Elixir 1 not working

straas

Hope someone can help on this one, I'll preface this by admitting I'm very unfamiliar with hydraulic brakes.

My front disc has been squealing when not braking for the past few rides, so I got round to looking at it today.

I assumed one of the pistons was stuck with dirt, so took out the pads cleaned around the pistons with an ear bud and then depressed the brake lever.

One piston appeared to move whilst the other didn't, so I pushed the moving piston back all the way then held it in place whilst pressing the brake lever till the other piston freed itself up.

Put everything back together, now the brake lever goes back all the way with very little pressure (certainly not enough to stop the bike)

I didn't notice the loss of any fluid during the process?

Any ideas?

cooldad

Pump it a bit, or use a rubber band around the lever and grip to hold the brake closed overnight.

The Rookie

You pushed the Pistons back, they now need to reset back to the point where the pads are just off the disc to work properly.

straas

Thanks.

Tried pumping, the pistons move a bit then retract. How many pumps (roughly) is normal to reset the pistons?

I'm wondering if when the pads were off I let a piston come out too far and drew air into the system?

cooldad

Doubtful, try the rubber band method.

straas

Cheers,

Will try tomorrow, the pads were quite worn and I managed to bend the spring (after I reinserted the wheel and spun it) so I've ordered a new set of pads (and a bleed kit in case this is the issue)

So:

- Insert pads
- Insert wheel / rotor
- pump brake
- keep brake lever depressed with rubber band

Is that the process?

cheers

cooldad

That's it.

straas

So, I put the new pads in the front but there wasn't enough clearance for the rotor.

Tried depressing the pistons, but they wouldn't retract all the way so I undid the fluid retaining screw on the caliper whilst applying pressure to the calipers till I lost some fluid, then closed the screw and released the pressure.

One of the pistons is flush but the other is 0.5 - 1mm proud, but this allows just enough clearance for the rotor.

Pumped the lever, and currently have it held with an elastic band nearly all the way to the bar.

straas

Seems to grab pretty well now, but the lever comes the majority of the way to the grip - is this normal or do I need to make adjustments?

Thanks for the help.

cooldad

As you've let fluid out, you need to put some back.

The pistons moved far enough for new pads before they wore out, they would have moved far enough to get the new pads in.

When trying to retract the pistons in future, leave the old pads in to prevent damage to the pistons, stick a big screwdriver in and turn it like a key.

straas

cooldad wrote:

As you've let fluid out, you need to put some back.

The pistons moved far enough for new pads before they wore out, they would have moved far enough to get the new pads in.

When trying to retract the pistons in future, leave the old pads in to prevent damage to the pistons, stick a big screwdriver in and turn it like a key.

Is it possible to add fluid without bleeding the system or introducing air?

I tried the old pad and screwdriver method but couldn't get them in all the way, they'd go back most of the way then push back out a little once I released pressure.

The Rookie

The bleed process is the only way to add fluid. If you dumped it out the bleed screw rather than pushing the diaphragm back its under filled so even though there is no air to bleed out the bleed process is the only way to fill it back up.

Generally with brakes it's best to sort out what you should do before you do something not after you've made a hash of it!

straas

I was really struggling to get the pistons to retract even under a good bit of pressure, and loosening the screw was advised when I did a google search

I assumed that the previous owner might have topped the oil up as the pads wore down?

The Rookie

Its possible it was over filled, but the correct process is then to bleed it out at the lever so you make sure the lever stays full, dump it out the calliper and you aren't making sure the lever is full!

straas

Cheers, noted for the future.

They say you only learn by your mistakes, so I must be learning a lot