Spongy brake lever

[Gemini]

hi guys,

me and baz overhauled my 6pot tokicos and replaced the seals along with cleaning all the toad out of them

bolted them back on, bled them and they stopping power is awesome - however, the brake lever is spongy and pulls back too close to the bar

any ideas how to sort this so they arent spongy and so i only have to tap them and they come on?

i have braided lines also

gem

[masterofinsanity]

we have also replaced the piston, spring and seals in the master cylinder.

[Gemini]

just had a thought,

the bleed nipple is on the lower part of the caliper, so maybe some air is getting trapped at a higher point?> being that air will rise...

does this seem likely?... maybe i should wedge the pads so the pistons dont pop out and hold the caliper so the nipple is at the highest point and bleed them

i could also reverse bleed them

gem

[masterofinsanity]

take em off mate and hold em up, give em a belt with a soft hammer (or several small taps) to dislodge any trapped air.

[cargo]

Almost certainly air in there somewhere

Did you use the right fluid..........and a really good quaility one at that ?

[Gemini]

think i will bring bike over to yours mate. cuz i cant hold caliper, whack with a hammer and bleed at same time

gem

[Gemini]

err, dunno.

so i need expensive good quality fluid?

is there anything else apart from trapped air that could do this? - worst case scenario

when the brakes come on the are well strong just cant live with the spongy feel

gem

[RedexRobB]

Did you use a fresh bottle of fluid? Not one thats been sat on the shelf open?

If they are still like it when i come up next Gem ill bring my vaccum bleeder and do them for you. Better than pumping with the lever anyday!

[deviant]

I can't see anything else that would cause it other than air in the system.

I always bleed brakes off the bike. It's much easier. Obv you need something you can clamp the lever/master cylinder to so you can pump it. Then when it's done just thread the master cylinder back up through the front end.

Your pistons shouldn't pop out if you have pads in there. But if you have an old pad or something kicking around you could stick that in there in place of the disc.

[cargo]

err, dunno.

so i need expensive good quality fluid?

is there anything else apart from trapped air that could do this? - worst case scenario

when the brakes come on the are well strong just cant live with the spongy feel

gem

Errrrrrrrrr yes brake fluid is one of those things that when you really really need your brakes to work it might just save you life.

So yes use good quaility brake fluid and use it from an unopened bottle. Once you are finished unless your going to change the fluid very regulary like once every race meeting throw whats left away.
Brake fluid has an affinity for water it soaks it up from the air and if you put contaiminated brake fluid in you bike once the fluid gets hot the water content boils.......................with very unpleasant results.

Apart from air or contaiminated fluid the only other thing it could be is a faulty seal somewhere?...........or a leak? or old rubber hoses?..............but you fitted new seal all round didn't you ?

[masterofinsanity]

fitted new dust seals caliper seals looked fine,polished the pistons and replaced hoses with braided lines, and replaced seals and piston in the master cylinder.

[Gemini]

right then baz, i think im gonna have to get some more fluid. then come over and bleed brakes off the bike or at least take off calipers from mountings and bleed them after whackin em with a hammer

gem

[masterofinsanity]

yeah take em off mate and start again i think, stick em in the vice.

[Gemini]

how dya mean? strip the calipers down again?

[masterofinsanity]

nah we'll get em off the bike and move em about see if we can dislodge any air.