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I have been following [url= http://www.singletrackworld.com/forum/topic/bleeding-brakes-how-to-an-idiots-guide?replies=43 ]Mr Nutt's venerable Formula brake bleed instructions [/url] but my lever still goes down to the bar and can be pumped up.
When I try again I can still pull air out of both ends of the system. I can't work out where I'm going wrong.
Using an Avid bleed kit, just like Mr Nutt's
I do the caliper with the lever closed; then the hose; replace the caliper screw, than the lever itself.
I pull the syringe almost all the way out to vacuum the air out of each end and try to get the torx screws back in without letting air in...
Any brake bleeder experts who can help?
Cheers
Are there any kinks in the hose? Air can hide in there, and not want to come out.
Otherwise the instructions are good, so just keep going until there is no air left - it can take a long time..
Have you made sure you have the very small o-ring under the bleed screws? I manged to loose one and suck the otherinto the system so was never going to get a propper bleed. Once i replaced both it works great.
Thanks for the replies both
al - no kinks. How long do i go for? I've gone through the process 4 times
Warrenpfo - yes, that little O ring is delicate isn't it, but it is still in plce
It's been a while since I last did mine, but I remember that it took a lot more than four goes to get it clear. It helps to flick the hose along its length each time before doing the 'hoovering' bit - this dislodges any bubbles that are hiding in the hose.
The o-ring can be a pain but you'll know if it's missing when the brake empties itself all over your bike / carpet / cat..
Make sure the lever is pointing vertically upwards.
Try bleeding the caliper with the pistons 'out' a little.
are you getting shut of that ninja air thats already in the fluid from the bottle?
Hey! It's Mr Nutt, my woes are surely over 😀
In answer to yours yes and no. I flicked the syringe to get the odd couple of big bubbles out, but if I pull the syringe to vacuum the fluid there are loads of ninja air bubbles all over the surface of the inside of the tube...
Rorschach - The lever was not in the upright position - is this what I'm doing wrong??
Also my pads are almost new so I didn't bother with the spacer or pushing them back flush
Never usually one thing-just another tip I got (from Toby,Mr Formula uk-he was a close 3rd in Mr Formula world).
"loads of ninja air bubbles all over the surface of the inside of the tube" those are the source of your woes, you need to keep pulling on that syringe, tapping it so they float to the top, doing it again, and again, and again and again. what you have with there is secretly carbonated brake fluid, you gotta purge it of the nightmare. you have to start all over again! sorry!
It took m3 3 full attempts to fully purge the system.
I found that taking the lever body off the bike and clamping it to a pole (in my case an upright ironing board) so that the access point is pointing straight up is the best method. Do it so that the lever body is as high as you can comfortably work on it as well.
Do the thing with the sryinges, de-pressurise them several times to get the air out of the fluid as well.
I'll bear that in mind for next time, thanks both
This time I gave up and the bike's down the lbs now...
you bought Formula- that's what you did wrong, -- speaks from experience.
I've bled Formula Oros without de-gassing the brake fluid but the master cylinder must be upright. Never been able to figure out why Formula don't include the hose clamps in the bleed kit when the system is practically identical to Avid's...
I bought some aquarium tube clamps of eBay for a couple of quid that work well but yeah they should be included in the Formula kit.