Brake bleeding and FRUSTRATION!!

boz64

Hello all.

Ok, first things first... I've searched the forum and can't find a solution to this problem. Apologies if I've missed an appropriate answer though!

I am utterly frustrated with trying to bleed my Avid Elixir 5 rear brake. It is brand new, but I had to cut the hose as it was too long. I used good quality tools (Park cable cutter), fitted the appropriate barb and pressure olive, and fitted the the hose back into the lever housing... all fine. I decided to bleed the brake as there was some fluid leakage from the hose when I cut it, and I wanted to make sure there were no air pockets in the system.

I have followed the SRAM bleed instructions, to the letter, three times now and yet the lever action still simply does not feel right. The lever pulls too far into the bars before activating the brake... its about an inch from the bars before it feels firm. Its almost as if there isn't enough fluid in the system, but I cannot see how I would get any more in there without over-filling it. It doesn't feel spongy... just too much lever movement. In comparison, the front brake (also brand new) has very little movement before it feels firm.

Please, please, please, can anyone shed any light on this as I am utterly frustrated with it!

I would be most grateful for any help.

Thanks
G

Chunkers1980

Don't get it. Can't overfill yet you're not sure there's enough, overfill to the point there's enough, so as to not overfill but enough

cooldad

Pump the lever 20 or 30 times, or go for a short ride and see if it sorts it out.

The Rookie

Advance the pads.......

boz64

Thanks for replies.

Chunkers... it only seems like there's not enough fluid in there due to the excessive lever movement. I know there is enough in there.

Beginner... no pad adjustment on Elixir 5.

Cooldad... pumped lever at least 40 or 50 times already!

bennett_346

My simple fix for this is to bleed them normally but using a bleed block a few mm thinner than the one Avid give you. It allows more fluid to be added to the system and reduces the dead lever throw.

sniper68

boz64 wrote:

Thanks for replies.
Beginner... no pad adjustment on Elixir 5.

He said "advance" the pads
From SRAM/Avid.

Avid disc brakes achieve the best ‘out of box’ performance when both the Pad Advancement and Disc Brake Pad and Rotor Bed-inprocedures are completed during the initial brake installation and setup. By performing these two procedures the rider will experience the best braking performance possible and prevent concerns related to improper set up later.
Pad Advancement Procedure
Avid disc brakes may ship with a pad spacer/bleed block installed in the caliper to prevent improper advancement of the pistons and pads during shipping. After removing a pad spacer, bleed block, or rotor and wheel, it may be necessary to perform the pad advancement procedure. Squeezing the brake lever once is not sufficient to properly advance the pads. Improper pad advancement can cause the brake lever to pull to the handlebar during installation which can be misdiagnosed as a poor brake bleed or other problem.
Be sure to complete the entire disc brake pad advancement procedure

1.If your brake is equipped with the contact adjustment feature on the lever body, turn the contact adjust barrel or screw in the
opposite direction of the arrow until it stops.
2.Remove the pad spacer/bleed block or rotor/wheel.
3.Slowly squeeze the brake lever several times until the pads are approximately 1 mm apart - about the thickness of a zip tie,and then release the brake lever. Repeat as necessary.
4.Insert the pad spacer/bleed block into the caliper. A moderate amount of force will be required to spread the pads outward to the correct position.
5.Install the wheel/rotor. Squeeze the brake lever several times; the brake should feel firm.
6.Align the caliper as needed. Adjust the reach and pad contact point to the rider’s preference

Dirty-Boy

Typical Avid, making it more complicated than it needs to be...

Neal_

It's nothing to do with under filling with fluid as they have a reservoir. Air in the system is the usual cause although advancing the pistons/pads may fix it. Using a toe clip strap or elastic band to pull the brake lever hard overnight can sort your problem temporarily as it allows the piston seals to creep on the pistons and dissolves tiny bubbles into the fluid.

Also use this as a guide for bleeding http://www.pinkbike.com/news/tech-tuesd ... -2010.html

If you don't sort it consider a warranty return and/or buy some Shimano brakes

boz64

bennett_346 wrote:

My simple fix for this is to bleed them normally but using a bleed block a few mm thinner than the one Avid give you. It allows more fluid to be added to the system and reduces the dead lever throw.

Thanks... this makes sense. Was considering doing this, but now I will try it for sure.

Ibbo68 - interesting reading. Never heard of/seen this before. Odd though, as front brake is just fine straight out of the box without pad "advancement". Anyway, thanks it is v useful to know.

The Rookie

bennett_346 wrote:

My simple fix for this is to bleed them normally but using a bleed block a few mm thinner than the one Avid give you. It allows more fluid to be added to the system and reduces the dead lever throw.

Which is overfilling and a bodge, it reduces or elminaites the expansion volume which is needed if the brakes get hot.

It can take a while for the seals (which control piston retraction) to move out, once settled they do it OK as the pads wear, but for the first time it can take a while. Often people think they've bled it wrong and start all over again, including pushing the pistons back!

bennett_346

I've never had any success with the pad advancing method on the last two pairs ive had but the overfilling has never caused me issues. They were overfilled when i went to the alps and they didn't have issues there despite getting very hot.

hard-rider

+1 for the pad advance. I had a similar problem to the OP. Lever pulled too far before there was any bite but was not spongy went it did bite. Although I didn't follow the pad advance procedure above, as I didn't know about it, with the wheel and pads out I simply pumped the lever a couple of times to push the pistons out a little then levered them back in just enough so there was enough clearance to fit the pads and allow the rotor to squeeze in. Once all assembled pumped the brake a few more times and it was all good. Lever now begins to bites within 5mm of pull.

steviecapt

i found the best solution to this problem is to insert two packers either side of the brake pads, i use a cut up credit card, this has the effect of firming up the levers also presurises the system, take out the packers and tie the brake lever back to the handle bar over night, hopefully this will solve your problem, works everytime for me